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Kousrali S, Kowtharapu LP, Mondal T. Analytical determination of ethylenediamine impurity in tripelennamine hydrochloride by gas chromatography-mass spectrometry using phthalaldehyde as the derivatizing agent. Biomed Chromatogr 2024; 38:e5850. [PMID: 38387606 DOI: 10.1002/bmc.5850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/21/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024]
Abstract
In the pharmaceutical industry, effective risk management and control strategies for potential genotoxic impurities are of paramount importance. The current study utilized GC-MS to evaluate a precise, linear, and accurate analytical method for quantifying ethylenediamine present in tripelennamine hydrochloride using phthalaldehyde as a derivatizing agent. When phthalaldehyde is sonicated for 10 min at room temperature, it reacts with ethylenediamine to form (1z,5z)-3,4-dihydrobenzo[f][1,4]diazocine. This approach minimizes matrix interference issues and resolves sample preparation difficulties encountered during ethylenediamine identification in GC-MS. In this method, helium serves as the carrier gas, while methanol acts as the diluent. The stationary phase consists of a DB-5MS column (30 m × 0.25 mm × 0.25 μm) with a flow rate of 1.5 mL/min. The retention time of (1z,5z)-3,4-dihydrobenzo[f][1,4]diazocine was determined to be 6.215 min. The method validation demonstrated limits of detection and quantification for (1z,5z)-3,4-dihydrobenzo[f][1,4]diazocine at 0.4 and 1.0 ppm, respectively, with a linearity range spanning from 1 to 30 ppm concentration with respect to the specification level. System suitability, precision, linearity, and accuracy of the current method were assessed in accordance with guidelines, yielding results deemed suitable for the intended use.
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Affiliation(s)
- Sayyad Kousrali
- Department of Engineering Chemistry, Koneru Lakshmaiah Education Foundation, Aziznagar, Hyderabad, Telangana, India
| | | | - Tanmoy Mondal
- Department of Engineering Chemistry, Koneru Lakshmaiah Education Foundation, Aziznagar, Hyderabad, Telangana, India
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Wang T, Wang Z, Wang R, Zhang L, Zhang Y, Lu H. Highly efficient and chemoselective blocking of free amino group by ortho-phthalaldehyde (OPA) for comprehensive analysis of protein terminome. Talanta 2024; 267:125262. [PMID: 37804787 DOI: 10.1016/j.talanta.2023.125262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/24/2023] [Accepted: 09/30/2023] [Indexed: 10/09/2023]
Abstract
Herein, we introduced ortho-phthalaldehyde (OPA) for blocking free amino groups and established a simple and robust method for comprehensive profiling of protein terminome based on strong cation exchange chromatography (SCX) fractionation. With the highly efficient and chemoseletive amine-group blocking, we identified 2271 canonical human protein N-termini, 1650 canonical human protein C-termini, as well as 645 protein neo-N-termini from HeLa cells.
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Affiliation(s)
- Ting Wang
- Department of Chemistry and Liver Cancer Institute of Zhongshan Hospital, Fudan University, Shanghai, 200032, China
| | - Zhongjie Wang
- Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China
| | - Rui Wang
- Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China
| | - Lei Zhang
- Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China
| | - Ying Zhang
- Department of Chemistry and Liver Cancer Institute of Zhongshan Hospital, Fudan University, Shanghai, 200032, China; Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China.
| | - Haojie Lu
- Department of Chemistry and Liver Cancer Institute of Zhongshan Hospital, Fudan University, Shanghai, 200032, China; Institutes of Biomedical Sciences and NHC Key Laboratory of Glycoconjugates Research, Fudan University, Shanghai, 200032, China.
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Dubey A, Joshi S, Upadhyay K, Mahato A, Rathore AS. Automated method for quantification of 20 amino acids in cell culture media during biopharmaceutical development. Biotechniques 2024; 76:27-36. [PMID: 37997819 DOI: 10.2144/btn-2023-0068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023] Open
Abstract
Herein, a step-by-step protocol for simultaneous detection of 20 amino acids commonly present in cell culture media is described. The protocol facilitates detection of both primary and secondary amino acids through a two-step precolumn derivatization strategy using ortho-phthalaldehyde and 9-fluorenylmethyl chloroformate as derivatizing agents. The separation of derivatized amino acids with varying hydrophobicity is achieved through reverse-phase chromatography. The amino acids are simultaneously detected in a single workflow through the use of Variable Wavelength Detector at 338 and 262 nm. The protocol is applicable for both mammalian and bacterial cell culture matrices with an option for automation of precolumn derivatization.
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Affiliation(s)
- Ankita Dubey
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
| | - Srishti Joshi
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
| | - Kratika Upadhyay
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
| | - Ansuman Mahato
- Centre of Excellence Lab, Agilent Technologies, Manesar, Gurugram, India
| | - Anurag S Rathore
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi, 110016, India
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El Hamd MA, Alshehri S, Abu-Hassan AA. An integrative analytical approach designed for feasible tranexamic acid assay using o-phthalaldehyde as a fluorogenic probe: applications to tablets, ampoules, and urine. LUMINESCENCE 2023; 38:1988-1995. [PMID: 36764931 DOI: 10.1002/bio.4463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 01/16/2023] [Accepted: 01/20/2023] [Indexed: 02/12/2023]
Abstract
Antifibrinolytic tranexamic acid (TRX) suppresses plasminogen activation to plasmin in a competitive way. TRX is approved for the management of heavy menstrual periods, hereditary angioedema, hemophilia, postpartum hemorrhage, surgery, tooth extraction, and severe blood loss after acute trauma. Here, the practical use of an isoindole derivative was established for a novel, easy-to-use, and affordable TRX assay. In the presence of a molecule containing a sulfhydryl group (2-mercaptoethanol) 0.02% v/v, the primary amine moiety in TRX allows its combination with o-phthalaldehyde to produce a luminous product. Excitation (338.8 nm) and emission (433.9 nm) wavelengths were used to monitor the isoindole fluorophore yield, and each operational variable was carefully examined and adjusted. The calibration graph was constructed with fluorescence intensity versus TRX concentration, excellent linearity was observed at concentrations between 40 and 950 ng/ml, and limit of detection and limit of quantitation were 41.3 and 13.6 ng/ml, respectively. The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use guidelines were used to validate the method. The developed method for TRX assay in various dosage forms and urine was successfully implemented and was shown to be an effective, simple, and quick replacement for the TRX assay in clinical trials and quality control.
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Affiliation(s)
- Mohamed A El Hamd
- Department of Pharmaceutical Sciences, College of Pharmacy, Shaqra University, Shaqra, Saudi Arabia
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, South Valley University, Qena, Egypt
| | - Sultan Alshehri
- Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed A Abu-Hassan
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Al-Azhar University, Assiut Branch, Assiut, Egypt
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Ntorkou M, Tsanaktsidou E, Chachlioutaki K, Fatouros DG, Markopoulou CK. In Vitro Permeability Study of Homotaurine Using a High-Performance Liquid Chromatography with Fluorescence Detection Pre-Column Derivatization Method. Molecules 2023; 28:7086. [PMID: 37894565 PMCID: PMC10609320 DOI: 10.3390/molecules28207086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/05/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
Homotaurine (HOM) is considered a promising drug for the treatment of Alzheimer's and other neurodegenerative diseases. In the present work, a new high-performance liquid chromatography with fluorescence detection (HPLC-FLD) (λex. = 340 nm and λem. = 455 nm) method was developed and validated for the study of substance permeability in the central nervous system (CNS). Analysis was performed on a RP-C18 column with a binary gradient elution system consisting of methanol-potassium phosphate buffer solution (pH = 7.0, 0.02 M) as mobile phase. Samples of homotaurine and histidine (internal standard) were initially derivatized with ortho-phthalaldehyde (OPA) (0.01 M), N-acetylcysteine (0.01 M) and borate buffer (pH = 10.5; 0.05 M). To ensure the stability and efficiency of the reaction, the presence of different nucleophilic reagents, namely (a) 2-mercaptoethanol (2-ME), (b) N-acetylcysteine (NAC), (c) tiopronin (Thiola), (d) 3-mercaptopropionic acid (3-MPA) and (e) captopril, was investigated. The method was validated (R2 = 0.9999, intra-day repeatability %RSD < 3.22%, inter-day precision %RSD = 1.83%, limits of detection 5.75 ng/mL and limits of quantification 17.43 ng/mL, recovery of five different concentrations 99.75-101.58%) and successfully applied to investigate the in vitro permeability of homotaurine using Franz diffusion cells. The apparent permeability (Papp) of HOM was compared with that of memantine, which is considered a potential therapeutic drug for various CNSs. Our study demonstrates that homotaurine exhibits superior permeability through the simulated blood-brain barrier compared to memantine, offering promising insights for enhanced drug delivery strategies targeting neurological conditions.
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Affiliation(s)
- Marianna Ntorkou
- Laboratory of Pharmaceutical Analysis, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (M.N.); (E.T.)
| | - Eleni Tsanaktsidou
- Laboratory of Pharmaceutical Analysis, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (M.N.); (E.T.)
| | - Konstantina Chachlioutaki
- Laboratory of Pharmaceutical Technology, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (K.C.); (D.G.F.)
| | - Dimitrios G. Fatouros
- Laboratory of Pharmaceutical Technology, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (K.C.); (D.G.F.)
| | - Catherine K. Markopoulou
- Laboratory of Pharmaceutical Analysis, Department of Pharmacy, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; (M.N.); (E.T.)
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Baltzis D, Tsogas GZ, Zacharis CK, Tzanavaras PD. Smartphone-Based High-Throughput Fluorimetric Assay for Histidine Quantification in Human Urine Using 96-Well Plates. Molecules 2023; 28:6205. [PMID: 37687035 PMCID: PMC10488697 DOI: 10.3390/molecules28176205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
A high-throughput fluorimetric assay for histidine was developed, using a 96-well plates platform. The analyte reacts selectively with o-phthalaldehyde under mild alkaline conditions to form a stable derivative. Instrumental-free detection was carried out using a smartphone after illumination under UV light (365 nm). The method was proved to be linear up to 100 μM histidine, with an LLOQ (lower limit of quantification) of 10 μM. The assay was only prone to interference from glutathione and histamine that exist in the urine samples at levels that are orders of magnitude lower compared to histidine. Human urine samples were analyzed following minimum treatment and were found to contain histidine in the range of 280 to 1540 μM. The results were in good agreement with an HPLC corroborative method.
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Affiliation(s)
- Dimitrios Baltzis
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (D.B.); (G.Z.T.)
| | - George Z. Tsogas
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (D.B.); (G.Z.T.)
| | - Constantinos K. Zacharis
- Laboratory of Pharmaceutical Analysis, School of Pharmacy, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece;
| | - Paraskevas D. Tzanavaras
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (D.B.); (G.Z.T.)
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Tsiasioti A, Iakovidou I, Zacharis CK, Tzanavaras PD. Automated fluorimetric sensor for glutathione based on zone fluidics. Spectrochim Acta A Mol Biomol Spectrosc 2020; 229:117963. [PMID: 31884397 DOI: 10.1016/j.saa.2019.117963] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 12/05/2019] [Accepted: 12/13/2019] [Indexed: 06/10/2023]
Abstract
A zone-fluidics (ZF) based automated fluorimetric sensor for the determination of glutathione (GSH) is reported. Discrete zones of GSH and o-phthalaldehyde (OPA) mix and react on-line under mild basic pH without the need of additional nucleophillic reagents, to yield a fluorescent isoindole derivative (λex/λem = 340/425 nm). The proposed ZF sensor was optimized (pH, c(OPA), time, instrumental variables) and validated. Cysteine, glutamate, glycine and ammonium were representatively examined in terms of selectivity and were found not to react in 10-fold excess. Linearity was proved in the range of 5-100 μmol L-1 GSH, with an LOD of 1 μmol L-1 at a practical sampling rate of 20 h-1 and RSD < 0.5% (within-day) and 4.2% (day-to-day). The dosage uniformity of commercially available GSH - containing nutraceuticals was evaluated.
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Affiliation(s)
- Apostolia Tsiasioti
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124, Greece
| | - Ifigenia Iakovidou
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124, Greece
| | - Constantinos K Zacharis
- Laboratory of Pharmaceutical Analysis, Department of Pharmaceutical Technology, School of Pharmacy, Aristotle University of Thessaloniki, GR-54124, Greece
| | - Paraskevas D Tzanavaras
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124, Greece.
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Senthil Kumar V, Kumaresan S, Tamizh MM, Hairul Islam MI, Thirugnanasambantham K. Anticancer potential of NF-κB targeting apoptotic molecule "flavipin" isolated from endophytic Chaetomium globosum. Phytomedicine 2019; 61:152830. [PMID: 31048125 DOI: 10.1016/j.phymed.2019.152830] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/02/2019] [Accepted: 01/09/2019] [Indexed: 05/13/2023]
Abstract
BACKGROUND Anticancer compounds from natural sources have drawn attention due to their structural diversity and relatively lesser side effects. Endophytic fungi are one such natural resource from, which plethoras of anticancerous compounds have been isolated. PURPOSE The objective of the study was to isolate and characterize the bioactive metabolite from Chaetomium globosum that exhibits astonishing antiproliferative activity against cancerous cell lines. METHODS Flavipin was isolated by bioassay-guided fractionation and identified using FT-IR, EI-MS and NMR studies. MTT assay was used to determine the cytotoxicity. Fluorescent staining (AO/EB) and DNA fragmentation studies confirmed the occurrence of apoptosis. Real time PCR and Western blotting were used to analyze the expression of apoptosis related genes and its proteins, respectively. RESULTS Flavipin inhibited proliferation of A549, HT-29 and MCF-7 cancer cells in dose dependent manner with an IC50 concentration of 9.89 µg/ml, 18 µg/ml and 54 µg/ml, respectively, whereas it was comparatively less sensitive (IC50 = 78.89 µg/ml) against normal cell line (CCD-18Co). At IC50 concentration cancerous cells exhibited cell shrinkage and fragmentation of DNA, which indicated that flavipin induced apoptotic cell death. In treated cells there is an up-regulation of p53 gene and its associated protein, whereas reciprocal expression was observed in BCL-2 gene and its protein. Furthermore, western blotting results also showed down-regulation of NFκB. CONCLUSION This is the first report on the antiproliferative activity of flavipin isolated from endophytic C. globosum and also proposed that interaction of flavipin with NFкB could be a possible mechanism for this activity. Flavipin induced apoptosis at low concentrations in cancer cell lines (A549, HT-29) and exhibited itself as a potential anticancer agent.
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Affiliation(s)
- Venugopal Senthil Kumar
- Department of Plant Biology and Plant Biotechnology, Ramakrishna Mission Vivekananda College, Mylapore, Chennai, Tamil Nadu 600 004, India; Pondicherry Centre for Biological Science and Educational Trust, Jawahar Nagar, Pondicherry 605 005, India
| | - Subramanian Kumaresan
- Department of Plant Biology and Plant Biotechnology, Ramakrishna Mission Vivekananda College, Mylapore, Chennai, Tamil Nadu 600 004, India.
| | - Manoharan Muthu Tamizh
- Department of Chemistry, Siddha Central Research Institute, Central Council for Research in Siddha, Arumbakkam, Chennai 600 106, Tamil Nadu, India
| | - Mohamed Ibrahim Hairul Islam
- Pondicherry Centre for Biological Science and Educational Trust, Jawahar Nagar, Pondicherry 605 005, India; Biological Sciences Department, College of Science, King Faisal University, Hofuf 31982 Al Hassa, Saudi Arabia
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Cuchiaro H, Laurens LML. Total Protein Analysis in Algae via Bulk Amino Acid Detection: Optimization of Amino Acid Derivatization after Hydrolysis with O-Phthalaldehyde 3-Mercaptopropionic Acid (OPA-3MPA). J Agric Food Chem 2019; 67:5672-5679. [PMID: 31017433 DOI: 10.1021/acs.jafc.9b00884] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The analysis of protein in algal biomass is one of the most critical areas of commercial development of algae characterization for nutritional or other high value applications. A new rapid and accurate method is required that can be widely implemented and that is free from interferences from the complex algal biomass matrix. We developed a simple spectrophotometric method for primary amino acid quantification bulk measurement in an acid hydrolyzed algal biomass preparation, as an alternative to the more labor-intensive amino HPLC acid analysis or less specific nitrogen-to-protein conversion. We have validated an O-phthalaldehyde (OPA)-based derivatization method, showing accurate and linear quantification for standard reference amino acids as well as mixtures, mimicking the amino acid complexity found in algal biomass. The presence of interferences that may be derived from the complex biomass biochemical composition was tested during the method validation phase. We document the application of a novel method of OPA derivatization with 3-mercaptopropionic acid (3MPA) to determine the total amino acid content of harvested algal biomass collected from different, controlled cultivation conditions and demonstrated a within 10% accuracy against a reference measurement of amino acid content in at least 4 species and 10 algal biomass samples, across early, mid, and late-stages of cultivation.
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Affiliation(s)
- Hunter Cuchiaro
- National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
| | - Lieve M L Laurens
- National Renewable Energy Laboratory , 15013 Denver West Parkway , Golden , Colorado 80401 , United States
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Abstract
Tryptophan is a nutritionally essential amino acid for both humans and animals. Besides acting as a building block for protein synthesis, tryptophan (Trp) and its metabolites are crucial for maintaining neurological function, immunity, and homeostasis in the body. To uncover the regulatory role of Trp and its metabolites in cell nutrition, metabolism and physiology, various analytical methods, including high-performance liquid chromatography (HPLC), have been developed to determine key Trp metabolites. Here we describe a rapid and sensitive method for the simultaneous analysis of Trp and its metabolites along with other amino acids by HPLC involving in-line pre-column derivatization with o-phthaldialdehyde (OPA) and dual-channel fluorescence detection. OPA reacts very rapidly (within 1 min) with Trp, 5-hydroxytryptophan, 5-hydroxytryptamine, and tryptamine at room temperature (e.g., 20-25 °C) in an autosampler. Their derivatives are immediately injected into the HPLC column without the need for extraction. Trp metabolites that cannot react with OPA but are fluorescent can be detected by setting the excitation and emission wavelengths of the fluorescence detector in another detection channel. The autosampler is programmed to mix Trp and its metabolites with OPA for 1 min to generate highly fluorescent derivatives for HPLC separation and detection (Channel A, excitation = 270 nm and emission = 350 nm; Channel B, excitation = 340 nm and emission = 450 nm). The detection limit for Trp and its metabolites is 30 pmol/mL or 150 fmol/injection. The total time for chromatographic separation (including column regeneration) is 55 min for each sample. Our HPLC method can be used for the analysis of amino acids (including Trp) in alkaline protein hydrolysates and of Trp and its metabolites in biological samples.
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Affiliation(s)
- Zhaolai Dai
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
| | - Shiqiang Sun
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Hui Chen
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Moyan Liu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Lianhua Zhang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Ju Li
- Henan Yinfa Animal Husbandry Co., Xinzheng, Henan, China
| | - Guoyao Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
- Department of Animal Science, Texas A&M University, College Station, TX, USA
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Wang S, Deng Y, Liu B, Li X, Lin X, Yuan D, Ma J. High-performance liquid chromatographic determination of 2-aminoethylphosphonic acid and 2-amino-3-phosphonopropionic acid in seawater matrix using precolumn fluorescence derivatization with o-phthalaldehyde-ethanethiol. J Chromatogr A 2018; 1571:147-154. [PMID: 30119975 DOI: 10.1016/j.chroma.2018.08.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 07/21/2018] [Accepted: 08/06/2018] [Indexed: 12/27/2022]
Abstract
2-Aminoethylphosphonic acid (2-AEP) and 2-amino-3-phosphonopropionic acid (2-AP3) are two types of abundant and ubiquitous naturally occurring phosphonates used as sources of phosphorus by many prokaryotic lineages. The potential utilization mechanism of 2-AEP and 2-AP3 in eukaryotic phytoplankton is currently under investigation. However, the lack of suitable analytical methods in saline samples are the limitation of such researches. Herein, a high-performance liquid chromatography (HPLC) method for monitoring 2-AEP and 2-AP3 using precolumn fluorescence derivatization with o-phthalaldehyde-ethanethiol (OPA-ET) in seawater matrix was developed. The derivatization procedure and HPLC conditions were carefully examined, which included optimization of the fluorescence excitation and emission wavelengths, the ammonium acetate concentration and pH of the mobile phase, the OPA-ET reagent content and composition and derivatization time. Because increasing salinity was observed to lower the derivatization efficiency, working standards were freshly prepared in artificial seawater with the same salinity as that of the samples for the quantification of 2-AEP and 2-AP3. The developed HPLC method showed a wide linear response with high linearity (R2 > 0.999) and high repeatability at three concentration levels. The relative standard deviation was less than 4.1% for 2-AEP and less than 1.7% for 2-AP3 (n = 7). The limits of detection for 2-AEP and 2-AP3 in artificial seawater matrix were both 12.0 μg/L. The recoveries were 83.0-104% for 2-AEP and 72.6-98.6% for 2-AP3 in different aqueous samples, including algal culture medium prepared with filtered seawater. These results indicated the matrix effect of this method was insignificant.
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Affiliation(s)
- Shu Wang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361102, Xiamen, Fujian, China
| | - Yao Deng
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361102, Xiamen, Fujian, China
| | - Baomin Liu
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, 361102, Xiamen, Fujian, China
| | - Xiaolin Li
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, 361102, Xiamen, Fujian, China
| | - Xin Lin
- State Key Laboratory of Marine Environmental Science, College of the Ocean and Earth Sciences, Xiamen University, 361102, Xiamen, Fujian, China
| | - Dongxing Yuan
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361102, Xiamen, Fujian, China
| | - Jian Ma
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, 361102, Xiamen, Fujian, China.
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Guan A, Wang Y, Phillips KS. An extraction free modified o-phthalaldehyde assay for quantifying residual protein and microbial biofilms on surfaces. Biofouling 2018; 34:925-934. [PMID: 30362370 DOI: 10.1080/08927014.2018.1521959] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 08/27/2018] [Accepted: 09/04/2018] [Indexed: 06/08/2023]
Abstract
Biological contamination of surfaces in industry and healthcare is an important vector of disease transmission. Current assays for detecting surface-adherent contamination require extraction of biological soil. However, physical inaccessibility or poor solubility may limit recovery. Here, how the o-phthalaldehyde (OPA) protein assay can be modified to measure residual protein (modeled with bovine serum albumin) or biofilm on a surface without extraction is described. The assay limit of detection (LOD) for protein was 1.6 µg cm-2. The detection threshold for Staphylococcus epidermis biofilm was 117 µg cm-2. The clinical utility of the method was demonstrated for measurements taken from clinically used endoscopes. Since this method is more sensitive than extraction-based testing, clinical results should not be compared with conventional benchmarks. By enabling direct detection and quantification of soils in complex or hard-to-reach areas, this method has potential to improve the margin of safety in medical and industrial cleaning processes.
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Affiliation(s)
- Allan Guan
- a Division of Biology, Chemistry and Materials Science, Center for Devices and Radiological Health , Office of Science and Engineering Laboratories, Office of Medical Products and Tobacco, United States Food and Drug Administration , Silver Spring , MD , USA
| | - Yi Wang
- a Division of Biology, Chemistry and Materials Science, Center for Devices and Radiological Health , Office of Science and Engineering Laboratories, Office of Medical Products and Tobacco, United States Food and Drug Administration , Silver Spring , MD , USA
| | - K Scott Phillips
- a Division of Biology, Chemistry and Materials Science, Center for Devices and Radiological Health , Office of Science and Engineering Laboratories, Office of Medical Products and Tobacco, United States Food and Drug Administration , Silver Spring , MD , USA
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13
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Omar MA, Mohamed AMI, Derayea SM, Hammad MA, Mohamed AA. An efficient spectrofluorimetric method adopts doxazosin, terazosin and alfuzosin coupling with orthophthalaldehyde: Application in human plasma. Spectrochim Acta A Mol Biomol Spectrosc 2018; 195:215-222. [PMID: 29414581 DOI: 10.1016/j.saa.2018.01.077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 11/30/2017] [Accepted: 01/30/2018] [Indexed: 05/06/2023]
Abstract
A new, selective and sensitive spectrofluorimetric method was designed for the quantitation of doxazosin (DOX), terazosin (TER) and alfuzosin (ALF) in their dosage forms and human plasma. The method adopts efficient derivatization of the studied drugs with ortho-phthalaldehyde (OPA), in the presence of 2-mercaptoethanol in borate buffer (pH9.7) to generate a highly fluorescent isoindole derivatives, which can strongly enhance the fluorescence intensities of the studied drugs, allowing their sensitive determination at 430nm after excitation at 337nm. The fluorescence-concentration plots were rectilinear over the ranges (10.0-400.0) ng/mL. Detection and quantification limits were found to be (0.52-3.88) and (1.59-11.76) ng/mL, respectively. The proposed method was validated according to ICH guidelines, and successfully applied for the determination of pharmaceutical preparations of the studied drugs. Moreover, the high sensitivity of the proposed method permits its successful application to the analysis of the studied drugs in spiked human plasma with % recovery (96.12±1.34-100.66±0.57, n=3). A proposal for the reaction mechanism was presented.
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Affiliation(s)
- Mahmoud A Omar
- Analytical Chemistry Department, Faculty of Pharmacy, Minia University, Minia, Egypt
| | - Abdel-Maaboud I Mohamed
- Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Assiut University, Assiut, Egypt
| | - Sayed M Derayea
- Analytical Chemistry Department, Faculty of Pharmacy, Minia University, Minia, Egypt.
| | - Mohamed A Hammad
- Analytical Chemistry Department, Faculty of Pharmacy, Sadat City University, Sadat City, Egypt
| | - Abobakr A Mohamed
- Analytical Chemistry Department, Faculty of Pharmacy, Minia University, Minia, Egypt
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14
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Saragadam T, Punekar NS. Novel Route for Agmatine Catabolism in Aspergillus niger: 4-Guanidinobutyrase Assay. Methods Mol Biol 2018; 1694:163-172. [PMID: 29080167 DOI: 10.1007/978-1-4939-7398-9_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The enzyme 4-guanidinobutyrase (GBase) catalyzes the hydrolysis of 4-guanidinobutyric acid (GB) to 4-aminobutyric acid (GABA) and urea. Here we describe methods to estimate urea and GABA that were suitably adapted from the published literature. The urea is determined by colorimetric assay using modified Archibald's method. However, the low sensitivity of this method often renders it impractical to perform fine kinetic analysis. To overcome this limitation, a high sensitive method for detecting GABA is exploited that can even detect 1 μM of GABA in the assay mixture. The samples are deproteinized by perchloric acid (PCA) and potassium hydroxide treatment prior to HPLC analysis of GABA. The method involves a pre-column derivatization with o-phthalaldehyde (OPA) in combination with the thiol 3-mercaptopropionic acid (MPA). The fluorescent GABA derivative is then detected after reversed phase high performance liquid chromatography (RP-HPLC) using isocratic elution. The protocols described here are broadly applicable to other biological samples involving urea and GABA as metabolites.
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Affiliation(s)
- Tejaswani Saragadam
- Metabolism and Enzymology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400 076, India
| | - Narayan S Punekar
- Metabolism and Enzymology Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, 400 076, India.
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15
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Zandy SL, Doherty JM, Wibisono ND, Gonzales RA. High sensitivity HPLC method for analysis of in vivo extracellular GABA using optimized fluorescence parameters for o-phthalaldehyde (OPA)/sulfite derivatives. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1055-1056:1-7. [PMID: 28433865 PMCID: PMC5536952 DOI: 10.1016/j.jchromb.2017.04.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 02/13/2017] [Accepted: 04/01/2017] [Indexed: 11/28/2022]
Abstract
Reversed-phase HPLC with derivatization using o-phthalaldehyde (OPA) and sulfite allows electrochemical detection of γ-aminobutyric acid (GABA) in microdialysis samples. However, OPA/sulfite derivatives have been reported to produce lower fluorescent yield than OPA derivatives using organic thiols as the nucleophile. To overcome this limitation we examined excitation and emission spectra, reaction time, pH, and concentration of reagents in the derivatization solution. Optimal detection parameters were determined as λex=220nm and λem=385nm for maximal fluorescence. The derivatization reaction occurred immediately and the product was stable up to 24 h [corrected]. A pH of 10.4 for the borate buffer used in the derivatization solution was significantly better than lower pH. Increasing the amount of sulfite combined with diluting the derivatization solution in borate buffer resulted in complete separation of the GABA peak from contaminants without any loss in signal. Controlling the temperature of the detector at 15°C significantly improved sensitivity with a detection limit of approximately 1nM. To validate this assay, we performed microdialysis in the dorsal striatum and ventral tegmental area (VTA) of adult Long Evans rats. GABA concentrations in dialysates were determined using external standards and standard additions, in order to further confirm interfering peaks were not present in biological samples. Within the dorsal striatum (n=4), basal GABA concentrations were 12.9±2.2 and 14.5±2.2nM (external and additions, respectively). Respective basal GABA concentrations in the VTA (n=3) were 4.6±1.1 and 5.1±0.6nM. Thus, we have developed a novel, sensitive fluorescence method to determine GABA in microdialysates using HPLC of an OPA/sulfite derivative.
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Affiliation(s)
- Shannon L Zandy
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - James M Doherty
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Nathan D Wibisono
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Rueben A Gonzales
- Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA.
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16
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Cui L, Guan XQ, Liu ZM, Fan LY, Li Q, Feng Y. A new pre-column derivatization for valienamine and beta-valienamine using o-phthalaldehyde to determine the epimeric purity by HPLC and application of this method to monitor enzymatic catalyzed synthesis of beta-valienamine. J Asian Nat Prod Res 2017; 19:347-357. [PMID: 28367638 DOI: 10.1080/10286020.2017.1292257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 02/03/2017] [Indexed: 06/07/2023]
Abstract
Valienamine and β-valienamine are representative C7 N aminocyclitols with significant glycosidase inhibition activity that have been developed as important precursors of drugs for diabetes and lysosomal storage diseases, respectively. The quantitative analysis of these chiral compounds is crucial for asymmetric in vitro biosynthetic processes for converting valienone into valienamine epimers using aminotransferase. Here, we developed an efficient and sensitive method for separation and quantitative analysis of chiral valienamine using reversed-phase high-performance liquid chromatography (HPLC) through o-phthalaldehyde (OPA) pre-column derivatization of the analytes. The epimers were derivatized by OPA in borate buffer (pH 9.0) at room temperature for 30 s, separated on an Eclipse XDB-C18 (5 μm, 4.6 × 150 mm) column, eluted with 22% acetonitrile at 30 °C for 18 min, and detected by a fluorescence detector using 445 nm emission and 340 nm excitation wavelengths. The average resolution of the epimers is 3.86, and the concentration linearity is in the range of 0.02-20 μg/ml. The method proved to be effective, sensitive, and reliable with good intra- and inter-day precision and accuracy, and successfully evaluated the enantiopreference and catalytic capability of the potential aminotransferases on an unnatural prochiral substrate, facilitating the design of an asymmetric biosynthetic route for optically pure valienamine and β-valienamine.
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Affiliation(s)
- Li Cui
- a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Xiao-Qing Guan
- a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Zhang-Min Liu
- a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Liu-Yin Fan
- a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Qian Li
- b School of Life Science & Technology , China Pharmaceutical University , Nanjing 210009 , China
| | - Yan Feng
- a State Key Laboratory of Microbial Metabolism, School of Life Science & Biotechnology, and Joint International Research Laboratory of Metabolic & Developmental Sciences , Shanghai Jiao Tong University , Shanghai 200240 , China
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17
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Maddukuri N, Zhang Q, Zhang N, Gong M. Rapid labeling of amino acid neurotransmitters with a fluorescent thiol in the presence of o-phthalaldehyde. Electrophoresis 2017; 38:507-512. [PMID: 27747885 PMCID: PMC5321804 DOI: 10.1002/elps.201600374] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/09/2016] [Accepted: 10/05/2016] [Indexed: 12/20/2022]
Abstract
LIF detection often requires labeling of analytes with fluorophores; and fast fluorescent derivatization is valuable for high-throughput analysis with flow-gated CE. Here, we report a fast fluorescein-labeling scheme for amino acid neurotransmitters, which were then rapidly separated and detected in flow-gated CE. This scheme was based on the reaction between primary amines and o-phthalaldehyde in the presence of a fluorescent thiol, 2-((5-fluoresceinyl)aminocarbonyl)ethyl mercaptan (FACE-SH). The short reaction time (<30 s) was suited for on-line mixing and derivatization that was directly coupled with flow-gated CE for rapid electrophoretic separation and sensitive LIF detection. To maintain the effective concentration of reactive FACE-SH, Tris(2-carboxyethyl)phosphine was added to the derivatization reagents to prevent thiol loss due to oxidation. This labeling scheme was applied to the detection of neurotransmitters by coupling in vitro microdialysis with online derivatization and flow-gated CE. It is also anticipated that this fluorophore tagging scheme would be valuable for on-chip labeling of proteins retained on support in SPE.
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Affiliation(s)
- Naveen Maddukuri
- Department of Chemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - Qiyang Zhang
- Department of Chemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - Ning Zhang
- Department of Chemistry, Wichita State University, Wichita, Kansas 67260, United States
| | - Maojun Gong
- Department of Chemistry, Wichita State University, Wichita, Kansas 67260, United States
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18
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Stasyuk N, Gayda G, Yepremyan H, Stepien A, Gonchar M. Fluorometric enzymatic assay of l-arginine. Spectrochim Acta A Mol Biomol Spectrosc 2017; 170:184-190. [PMID: 27450117 DOI: 10.1016/j.saa.2016.07.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 07/07/2016] [Accepted: 07/09/2016] [Indexed: 06/06/2023]
Abstract
The enzymes of l-arginine (further - Arg) metabolism are promising tools for elaboration of selective methods for quantitative Arg analysis. In our study we propose an enzymatic method for Arg assay based on fluorometric monitoring of ammonia, a final product of Arg splitting by human liver arginase I (further - arginase), isolated from the recombinant yeast strain, and commercial urease. The selective analysis of ammonia (at 415nm under excitation at 360nm) is based on reaction with o-phthalaldehyde (OPA) in the presence of sulfite in alkali medium: these conditions permit to avoid the reaction of OPA with any amino acid. A linearity range of the fluorometric arginase-urease-OPA method is from 100nM to 6μМ with a limit of detection of 34nM Arg. The method was used for the quantitative determination of Arg in the pooled sample of blood serum. The obtained results proved to be in a good correlation with the reference enzymatic method and literature data. The proposed arginase-urease-OPA method being sensitive, economical, selective and suitable for both routine and micro-volume formats, can be used in clinical diagnostics for the simultaneous determination of Arg as well as urea and ammonia in serum samples.
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Affiliation(s)
- Nataliya Stasyuk
- Institute of Cell Biology, National Academy of Science of Ukraine, Drahomanov Str. 14/16, 79005 Lviv, Ukraine
| | - Galina Gayda
- Institute of Cell Biology, National Academy of Science of Ukraine, Drahomanov Str. 14/16, 79005 Lviv, Ukraine.
| | - Hasmik Yepremyan
- Scientific and Production Center "Armbiotechnology", National Academy of Sciences of Armenia, Armenia
| | - Agnieszka Stepien
- Department of Dietetics, Institute of Nursing and Health Sciences, Medical Faculty, University of Rzeszow, Al. mjr.W.Kopisto 2 a, 35-310 Rzeszów, Poland; Centre for Innovative Research in Medical and Natural Sciences, Medical Faculty of the University of Rzeszow, Warzywna 1A, 35-310 Rzeszów, Poland
| | - Mykhailo Gonchar
- Institute of Cell Biology, National Academy of Science of Ukraine, Drahomanov Str. 14/16, 79005 Lviv, Ukraine
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19
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Rausch KM, Zhu D. Determination of Protein Content in Alhydrogel ®-Based Vaccines by O-Phthalaldehyde Assay. Methods Mol Biol 2017; 1494:263-271. [PMID: 27718200 DOI: 10.1007/978-1-4939-6445-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The quantification of antigens adsorbed to aluminum-based adjuvants (alum) typically involves a method that first extracts antigen from the alum followed by the quantification of the antigen available in the extract. Extraction procedures often result in less than 100 % desorption of the antigen from the alum adjuvant and may alter the conformation of the antigen, reducing the accuracy of the subsequent method used for quantification. There is no generic method available for directly assessing the protein content when formulated on alum. Here we offer a method that can directly quantify protein adsorbed to Alhydrogel® using a simple fluorescence assay that is highly accurate and reproducible for Alhydrogel® formulations containing 25-400 μg/mL of antigen.
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Affiliation(s)
- Kelly M Rausch
- Laboratory of Malaria Immunology and Vaccinology, National Institutes of Allergy and Infectious Disease, National Institutes of Health, 5640 Fishers Lane, Rockville, MD, 20852, USA.
| | - Daming Zhu
- Laboratory of Malaria Immunology and Vaccinology, National Institutes of Allergy and Infectious Disease, National Institutes of Health, 5640 Fishers Lane, Rockville, MD, 20852, USA.
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20
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Oyelakin O, Traoré M, Mbaye EHB, Konté A, Cissé L, Faye AN, Faye O, Mbaye M, Kital K, Seye G, Coly A, Tine A, Delattre F. Spectrofluorometric Determination of Putrescine Using Orthophthaldehyde as a Fluorophore: A Novel Method. J AOAC Int 2016; 99:170-3. [PMID: 26856313 DOI: 10.5740/jaoacint.15-0212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This paper concerns spectrofluorometric analysis of putrescine using orthophthaladehyde as a fluorophore in aqueous alkaline medium. Wavelengths of excitation and emission in acid, neutral, and alkaline media were different. There is a maximum intensity of fluorescence in alkaline medium 24 h after complexation compared with other media. Putrescine and orthophthaladehyde are used at an equimolar ratio, and the product is kinetically stable in alkaline medium. Calibration curves obtained gave limits of detection and quantification of 39 and 65 ng/mL, respectively. The correlation coefficient obtained in alkaline medium was 0.992 at pH 12. Results obtained largely showed a good reproducibility of our method.
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Affiliation(s)
- Oladele Oyelakin
- University of The Gambia, School of Arts and Sciences, Division of Physical and Natural Sciences, Gambia
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21
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Arosio P, Müller T, Rajah L, Yates EV, Aprile FA, Zhang Y, Cohen SIA, White DA, Herling TW, De Genst EJ, Linse S, Vendruscolo M, Dobson CM, Knowles TPJ. Microfluidic Diffusion Analysis of the Sizes and Interactions of Proteins under Native Solution Conditions. ACS Nano 2016; 10:333-41. [PMID: 26678709 DOI: 10.1021/acsnano.5b04713] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Characterizing the sizes and interactions of macromolecules under native conditions is a challenging problem in many areas of molecular sciences, which fundamentally arises from the polydisperse nature of biomolecular mixtures. Here, we describe a microfluidic platform for diffusional sizing based on monitoring micron-scale mass transport simultaneously in space and time. We show that the global analysis of such combined space-time data enables the hydrodynamic radii of individual species within mixtures to be determined directly by deconvoluting average signals into the contributions from the individual species. We demonstrate that the ability to perform rapid noninvasive sizing allows this method to be used to characterize interactions between biomolecules under native conditions. We illustrate the potential of the technique by implementing a single-step quantitative immunoassay that operates on a time scale of seconds and detects specific interactions between biomolecules within complex mixtures.
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Affiliation(s)
- Paolo Arosio
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Thomas Müller
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
- Fluidic Analytics Ltd. , Cambridge CB2 1EW, U.K
| | - Luke Rajah
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Emma V Yates
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Francesco A Aprile
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Yingbo Zhang
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Samuel I A Cohen
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Duncan A White
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Therese W Herling
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Erwin J De Genst
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Sara Linse
- Department of Biochemistry and Structural Biology, Lund University , Box 124, SE221 00 Lund, Sweden
| | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
| | - Tuomas P J Knowles
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge CB2 1EW, U.K
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22
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Park CW, Kang SK, Hernandez HL, Kaitz JA, Wie DS, Shin J, Lee OP, Sottos NR, Moore JS, Rogers JA, White SR. Thermally triggered degradation of transient electronic devices. Adv Mater 2015; 27:3783-8. [PMID: 25991389 DOI: 10.1002/adma.201501180] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Indexed: 05/23/2023]
Abstract
Thermally triggered transient electronics using wax-encapsulated acid, which enable rapid device destruction via acidic degradation of the metal electronic components are reported. Using a cyclic poly(phthalaldehyde) (cPPA) substrate affords a more rapid destruction of the device due to acidic depolymerization of cPPA.
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Affiliation(s)
- Chan Woo Park
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Seung-Kyun Kang
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Hector Lopez Hernandez
- Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Joshua A Kaitz
- Department of Chemistry Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Dae Seung Wie
- Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jiho Shin
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Olivia P Lee
- Department of Chemistry Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Nancy R Sottos
- Department of Materials Science and Engineering Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Jeffrey S Moore
- Department of Chemistry Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - John A Rogers
- Department of Materials Science and Engineering, Chemistry, Mechanical Science and Engineering Electrical and Computer Engineering, Beckman Institute for Advanced Science and Technology, and Frederick Seitz Materials, Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Scott R White
- Department of Aerospace Engineering Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
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23
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Perucho J, Gonzalo-Gobernado R, Bazan E, Casarejos MJ, Jiménez-Escrig A, Asensio MJ, Herranz AS. Optimal excitation and emission wavelengths to analyze amino acids and optimize neurotransmitters quantification using precolumn OPA-derivatization by HPLC. Amino Acids 2015; 47:963-73. [PMID: 25691143 PMCID: PMC4412611 DOI: 10.1007/s00726-015-1925-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/17/2015] [Indexed: 11/26/2022]
Abstract
We describe an analytical methodology to obtain high sensitivity and better resolution through the study of fluorometric excitation (λex) and emission (λem) spectrum wavelengths of OPA-amino acids. The spectrum emission study revealed a maximum signal peak at 450 nm for aspartate and glutamine. For glycine, taurine, and GABA, the maximum signal peak was at 448 and for glutamate at 452 nm. The remaining amino acids analyzed showed a maximum emission around 450 nm. The best signal obtained within the spectrum excitation experiments was using 229- to 450-nm λex-λem. The drawbacks observed at these wavelengths were a baseline drift and negative peaks occurrence. Thus, the excitation wavelength of 240 nm was chosen (240- to 450-nm λex-λem) as a compromise between a very good signal response and a baseline stability to resolve the 18 amino acids studied. Furthermore, this protocol was properly validated. On the other hand, the elution gradient program used for neuroactive amino acids (aspartate, glutamate, glycine, taurine and GABA) showed separation to the baseline, in a 15-min run in all of them. Other amino acids, up to 18, also exhibited a very good separation in a 25-min run. In conclusion, we propose the use of 240- to 450-nm λex-λem wavelengths, in OPA-amino acids analysis, as the most suitable protocol to obtain the best signal response, maintaining an optimum chromatographic resolution.
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Affiliation(s)
- J. Perucho
- Neuropharmacology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
- CIBERNED, Madrid, Spain
| | - R. Gonzalo-Gobernado
- Neurobiology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
| | - E. Bazan
- Neurobiology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
| | - M. J. Casarejos
- Neuropharmacology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
- CIBERNED, Madrid, Spain
| | - A. Jiménez-Escrig
- Neurobiology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
| | - M. J. Asensio
- Neurobiology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
| | - A. S. Herranz
- Neurobiology Laboratory, Neurobiology-Research Service, Hospital Universitario Ramón y Cajal, IRYCIS, Carretera de Colmenar, km 9,1, 28034 Madrid, Spain
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24
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Hiraguchi H, Kaketani M, Hirose H, Kikuchi H, Yoneyama T. Surface porosity of stone casts resulting from immersion of addition silicone rubber impressions in disinfectant solutions. INT J PROSTHODONT 2014; 27:567-9. [PMID: 25390872 DOI: 10.11607/ijp.3967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study investigated the effects of immersion of addition silicone rubber impressions in disinfectant solutions on the surface porosity of the resulting stone casts. Five brands of type 2 and 3 addition silicone rubber impression materials and one brand of type 4 dental stone were used. Impressions of a master die designed to simulate an abutment tooth were immersed in disinfectant for 30 minutes. The disinfectants used were 2% glutaraldehyde solution and 0.55% ortho-phthalaldehyde solution. The surface porosities of stone casts obtained from two brands of impression materials immersed in disinfectant for 30 minutes were determined. Results suggest that impression materials immersed in disinfectant solutions need sufficient time before pouring into dental stone.
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Cao D, Tu M, Xie R, Li J, Wu Y, Adhikari S. Inhibitory activity of carbonyl compounds on alcoholic fermentation by Saccharomyces cerevisiae. J Agric Food Chem 2014; 62:918-926. [PMID: 24401115 DOI: 10.1021/jf405711f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Aldehydes and acids play important roles in the fermentation inhibition of biomass hydrolysates. A series of carbonyl compounds (vanillin, syringaldehyde, 4-hydroxybenzaldehyde, pyrogallol aldehyde, and o-phthalaldehyde) were used to examine the quantitative structure-inhibitory activity relationship of carbonyl compounds on alcoholic fermentation, based on the glucose consumption rate and the final ethanol yield. It was observed that pyrogallol aldehyde and o-phthalaldehyde (5.0 mM) reduced the initial glucose consumption rate by 60 and 89%, respectively, and also decreased the final ethanol yield by 60 and 99%, respectively. Correlating the molecular descriptors to inhibition efficiency in yeast fermentation revealed a strong relationship between the energy of the lowest unoccupied molecular orbital (ELUMO) of aldehydes and their inhibitory efficiency in fermentation. On the other hand, vanillin, syringaldehyde, and 4-hydroxybenzaldehyde (5.0 mM) increased the final ethanol yields by 11, 4, and 1%, respectively. Addition of vanillin appeared to favor ethanol formation over glycerol formation and decreased the glycerol yield in yeast fermentation. Furthermore, alcohol dehydrogenase (ADH) activity dropped significantly from 3.85 to 2.72, 1.83, 0.46, and 0.11 U/mg at 6 h of fermentation at vanillin concentrations of 0, 2.5, 5.0, 10.0, and 25.0 mM correspondingly. In addition, fermentation inhibition by acetic acid and benzoic acid was pH-dependent. Addition of acetate, benzoate, and potassium chloride increased the glucose consumption rate, likely because the salts enhanced membrane permeability, thus increasing glucose consumption.
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Affiliation(s)
- Dongxu Cao
- Forest Products Laboratory and Center for Bioenergy and Bioproducts, Auburn University , 520 Devall Drive, Auburn, Alabama 36849, United States
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Rigobello-Masini M, Masini JC. Improvements in the separation capabilities of sequential injection chromatography: determination of intracellular dissolved free amino acid profiles in three taxonomic groups of microalgae. Phytochem Anal 2013; 24:224-229. [PMID: 23055332 DOI: 10.1002/pca.2402] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 08/07/2012] [Accepted: 08/20/2012] [Indexed: 06/01/2023]
Abstract
INTRODUCTION Dissolved free amino acids (DFAA) in intracellular extracts of marine microalgae can be determined by sequential injection chromatography (SIC). This technique uses portable, low-cost instrumentation but its applications have been limited to short monolithic columns because of components not resistant to high pressures. OBJECTIVE To develop a SIC method for determination of DFAA by exploring an instrument modified to handle pressures of 1000 psi. METHOD The method was based on pre-column derivatisation of the amino acids with o-phthalaldehyde and 2-mercaptoethanol in borate buffer (pH 9.4), separation and fluorimetric detection (λ(excitation)= 340 and λ(emission)= 450 nm). Separation was achieved by stepwise gradient elution using six mobile phases. The first elution step used a mobile phase composed of methanol:tetrahydrofuran:10 mm phosphate buffer (pH 7.2) at a volumetric ratio of 8:1:91. Additional elution steps used mobile phases containing methanol and 10 mM phosphate buffer at ratios of 17.5:82.5, 25:75, 35:65, 50:50 and 65:35. RESULTS Nineteen chromatographic peaks were observed in a mixture of 20 amino acids. The only complete co-elution was between tryptophan and methionine. Detection limits varied from 0.10 µm for isoleucine to 1.5 µm for lysine. Recoveries from spiked extracts were between 84 and 131%. CONCLUSION Resolutions of the amino acid pairs glutamine and histidine, valine and phenylalanine, and isoleucine and leucine were 1.5, 0.75 and 1.3, respectively. The proposed method found different profiles of DFAA among the three species of algae, suggesting its adequacy for metabolic studies.
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Moliner-Martínez Y, Herráez-Hernández R, Molins-Legua C, Verdú-Andrés J, Avella-Oliver M, Campíns-Falcó P. More about sampling and estimation of mercaptans in air samples. Talanta 2013; 106:127-32. [PMID: 23598104 DOI: 10.1016/j.talanta.2012.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Revised: 11/29/2012] [Accepted: 12/03/2012] [Indexed: 11/19/2022]
Abstract
Several strategies have been developed for sampling and determination of volatile thiols. The selectivity and sensitivity of the proposed methodologies are achieved by using a specific derivatizing reagent. The different procedures assayed are based on air sampling followed by derivatization of the analytes with OPA and isoleucine in alkaline solution. The derivatization products are separated and determined by liquid chromatography and fluorescence detection. To start, the derivatization conditions and stability of the derivates have been studied in order to establish the storage conditions. In general, the strategies studied consisted on trapping and detivatization the thiol compound on different support; a solution (Impinger) or sorbent (C₁₈ cartridges or glass fiber filter). The analytical properties of the different strategies have been obtained and compared. Procedures are recommended upon specific situations.
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Affiliation(s)
- Y Moliner-Martínez
- Departamento de Química Analítica, Facultad de Química, Universidad de Valencia, C/Dr. Moliner 50, - Burjassot, Valencia E46100, Spain
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Caboni P, Aissani N, Cabras T, Falqui A, Marotta R, Liori B, Ntalli N, Sarais G, Sasanelli N, Tocco G. Potent nematicidal activity of phthalaldehyde, salicylaldehyde, and cinnamic aldehyde against Meloidogyne incognita. J Agric Food Chem 2013; 61:1794-1803. [PMID: 23379671 DOI: 10.1021/jf305164m] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The nematicidal activity of selected aromatic aldehydes was tested against the root knot nematode Meloidogyne incognita. The most active aldehyde was phthalaldehyde (1) with an EC(50) value of 11 ± 6 mg/L followed by salicylaldehyde (2) and cinnamic aldehyde (3) with EC(50) values of 11 ± 1 and 12 ± 5 mg/L, respectively. On the other hand, structurally related aldehydes such as 2-methoxybenzaldehyde (21), 3,4-dimethoxybenzaldehyde, and vanillin (23) were not active at the concentration of 1000 mg/L. By liquid chromatography-mass spectrometry the reactivity of tested aldehydes against a synthetic peptide resembling the nematode cuticle was characterized. At the test concentration of 1 mM, the main adduct formation was observed for 3,4-dihydroxybenzaldehyde (22), 2-methoxybenzaldehyde (21), and 3,4-dimethoxybenzaldehyde. Considering that 2-methoxybenzaldehyde (21) and 3,4-dimethoxybenzaldehyde were not active against M. incognita in in vitro experiments led us to hypothesize a different mechanism of action rather than an effect on the external cuticle modification of nematodes. When the toxicity of the V-ATPase inhibitor pyocyanin (10) was tested against M. incognita J2 nematodes, an EC(50) at 24 h of 72 ± 25 mg/L was found. The redox-active compounds such as phthalaldehyde (1) and salicylaldehyde (2) may share a common mode of action inhibiting nematode V-ATPase enzyme. The results of this investigation reveal that aromatic redox-active aldehydes can be considered as potent nematicides, and further investigation is needed to completely clarify their mode of action.
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Affiliation(s)
- Pierluigi Caboni
- Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.
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Cao CP, Lin W, Hu MH, Huang ZB, Shi DQ. Highly efficient construction of pentacyclic benzo[b]indeno-[1,2,3-de][1,8]naphthyridine derivatives via four-component domino reaction. Chem Commun (Camb) 2013; 49:6983-5. [PMID: 23802198 DOI: 10.1039/c3cc43489c] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Cheng-Pao Cao
- Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, PR China
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Liu J, Ma J, Zhang H, Wang H. The effect of zinc ion on the absorption and emission spectra of glutathione derivative: predication by ab initio and DFT methods. Spectrochim Acta A Mol Biomol Spectrosc 2012; 91:307-313. [PMID: 22387681 DOI: 10.1016/j.saa.2012.01.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 01/02/2012] [Accepted: 01/18/2012] [Indexed: 05/31/2023]
Abstract
Relying on the reaction of o-phthalaldehyde (OPA) with glutathione (GSH) to form a highly fluorescence derivative GSH-OPA has been widely used to measure reduced glutathione. In order to better understand spectra property of the GSH-OPA and the effect of zinc ion on it, the ground and the lowest singlet excited state properties, the electronic absorption and emission spectra are predicted by ab initio and DFT methods. The absorption spectra are simulated using time dependent DFT method (TD-DFT) whereas the emission spectra are approximated by optimizing the lowest singlet excited state by HF/CI-Singles and then subsequently using this geometry for the TD-DFT calculations. The solvent effects on transition energies have been described within the conductor-like polarizable continuum model (CPCM). The calculated transition energies (absorption and emission) are in agreement with available experimental information.
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Affiliation(s)
- Jianhua Liu
- School of Chemical and Material Engineering, Jiangnan University, Wuxi, Jiangsu 214122, PR China
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Böhmer A, Jordan J, Tsikas D. High-performance liquid chromatography ultraviolet assay for human erythrocytic catalase activity by measuring glutathione as o-phthalaldehyde derivative. Anal Biochem 2010; 410:296-303. [PMID: 21094119 DOI: 10.1016/j.ab.2010.11.026] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 11/04/2010] [Accepted: 11/11/2010] [Indexed: 02/02/2023]
Abstract
The most frequently used catalase (CAT) activity assay is based on the spectrophotometric measurement of hydrogen peroxide (H(2)O(2)) absorbance decrease at 240 nm. Here we report an alternative high-performance liquid chromatography (HPLC) assay for human erythrocytic CAT (heCAT) activity measurement based on glutathione (GSH) analysis as a highly stable, H(2)O(2)-insensitive o-phthalaldehyde (OPA) derivative. The method was developed and validated using an isolated heCAT in phosphate-buffered saline at pH 7.4 and was applied to measure CAT activity in lysed human erythrocytes. heCAT activity was measured at initial concentrations of 5 nM for heCAT, 5mM for H(2)O(2), and 10mM for GSH, and the incubation time was 10 min. Nitrite (NO(2)(-)) was found to be an uncompetitive inhibitor of heCAT activity (IC(50)=9 μM) and of CAT activity in hemolysate (IC(50)∼750 μM). Nitrate (NO(3)(-)) at concentrations up to 100 μM did not inhibit heCAT activity. Azide (N(3)(-)) was found to be a very strong inhibitor of the heCAT (IC(50)=0.2 nM) but a relatively weak CAT inhibitor (IC(50)∼10 μM) in human hemolysates. The novel CAT activity assay works under redox conditions that more closely resemble those prevailing in cells and allows high-throughput analysis despite the required HPLC step.
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Affiliation(s)
- Anke Böhmer
- Institute of Clinical Pharmacology, Hannover Medical School, 30625 Hannover, Germany
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Karthikeyan K, Arularasu GT, Ramadhas R, Pillai KC. Development and validation of indirect RP-HPLC method for enantiomeric purity determination of D-cycloserine drug substance. J Pharm Biomed Anal 2010; 54:850-4. [PMID: 21075575 DOI: 10.1016/j.jpba.2010.10.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 10/11/2010] [Accepted: 10/18/2010] [Indexed: 11/19/2022]
Abstract
A new chiral purity method was developed for D-cycloserine (D-cys) by reverse phase HPLC and validated. Chiral derivatizing reagents, viz., o-phthalaldehyde and N-acetyl-L-cysteine were utilized in this method. The resultant diastereomers were resolved using Zorbax SB Phenyl HPLC column under isocratic elution. A mobile phase of 95:05 (v/v), 20mM Na(2)HPO(4) (pH 7), and acetonitrile, respectively, was used with the flow rate of 1.0 mL/min and UV detection at 335 nm. The method development with different chiral stationary phases and chiral derivatization reagents were also investigated. The stability of diastereomer derivative and influence of organic modifier and pH of the mobile phase were studied and optimized. The stability-indicating capability of the method was established by performing stress studies under acidic, basic, oxidation, light, humidity and thermal conditions. The detection and quantitation limit of L-cycloserine (L-cys) were 0.015 and 0.05% (w/w), respectively. A linear range from 0.05 to 0.30% (w/w) was obtained with the coefficient of determination (r(2)) 0.998. The recovery obtained for L-cys was between 92.9 and 100.2%. This method was applied successfully in pharmaceutical analysis to determine the content of L-cys in D-cys bulk drug.
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Affiliation(s)
- K Karthikeyan
- Analytical Development, Shasun Research Center, 27 Vandalur Kelambakkam Road, Keelakottaiyur, Chennai, India.
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Rutherfurd SM. Methodology for determining degree of hydrolysis of proteins in Hydrolysates: a review. J AOAC Int 2010; 93:1515-1522. [PMID: 21140664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Degree of hydrolysis (DH) is defined as the proportion of cleaved peptide bonds in a protein hydrolysate. Several methods exist for determining DH; the most commonly used of these include the pH-stat, trinitrobenzenesulfonic acid (TNBS), o-phthaldialdehyde (OPA), trichloroacetic acid soluble nitrogen (SN-TCA), and formol titration methods. The pH-stat method is based on the number of protons released during hydrolysis; the TNBS, OPA, and formol titration methods are based on the measurement of amino groups generated from hydrolysis. The SN-TCA method measures the amount of TCA-soluble nitrogen, rather than DH. The pH-stat is the simplest and most commonly used method, but does not determine peptide bonds directly. In addition, the accuracy of the method depends on the type of hydrolytic enzymes used, the size of the hydrolyzed peptides, and the reaction temperature. Generally, the TNBS and OPA methods compare well and do directly determine DH. However, the assumption that the response factor for all derivatized N-terminal amino acids is similar may lead to inaccuracies. In conclusion, there is no consensus as to the best method for determining the DH of protein hydrolysates; consequently, there is a need for a standardized approach if interstudy comparisons are to be made.
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Serve KM, Darnell JL, Takemoto JK, Davies NM, Black ME. Validation of an isocratic HPLC method to detect 2-fluoro-beta-alanine for the analysis of dihydropyrimidine dehydrogenase activity. J Chromatogr B Analyt Technol Biomed Life Sci 2010; 878:1889-92. [PMID: 20570578 PMCID: PMC2902665 DOI: 10.1016/j.jchromb.2010.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 05/04/2010] [Accepted: 05/06/2010] [Indexed: 10/19/2022]
Abstract
The efficacy of the chemotherapeutic drug 5'-fluorouracil is reduced by catabolism to 2'-fluoro-beta-alanine (FBAL), a three-step reaction in which dihydropyrimidine dehydrogenase (DPD) catalyzes the rate-limiting step. To study in vitro DPD activity, we developed and validated an isocratic, reverse-phase HPLC method to detect and quantify FBAL without using multiple columns or radiolabeled substrates. Pre-column derivatization of FBAL was performed using o-phthalaldehyde in the presence of two sulfur donors, ethanthiol or beta-mercaptoethanol, and the resulting products assayed. Calibration curves were linear over a range of 10-200 microg/ml and the method was successfully applied to the examination of DPD activity in cultured cells.
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Affiliation(s)
- Kinta M. Serve
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA, 99164
| | - Jennifer L. Darnell
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA, 99164
| | - Jody K. Takemoto
- Department of Pharmaceutical Sciences, Washington State University, Pullman, Washington, USA, 99164
| | - Neal M. Davies
- Department of Pharmaceutical Sciences, Washington State University, Pullman, Washington, USA, 99164
| | - Margaret E. Black
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA, 99164
- Department of Pharmaceutical Sciences, Washington State University, Pullman, Washington, USA, 99164
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Su YS, Lin YP, Cheng FC, Jen JF. In-capillary derivatization and stacking electrophoretic analysis of gamma-aminobutyric acid and alanine in tea samples to redeem the detection after dilution to decrease matrix interference. J Agric Food Chem 2010; 58:120-126. [PMID: 20000401 DOI: 10.1021/jf902958u] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An in-capillary derivatization and stacking capillary electrophoresis (CE) technique has been applied to redeem the detection of dilute analytes in the analysis of gamma-aminobutyric acid (GABA) and alanine (Ala) in tea samples. Extracts from samples were diluted to eliminate matrix interference before introduction into the CE system. GABA and Ala in the diluted sample zone were derivatized with o-phthaldialdehyde/2-mercaptoethanol (OPA/2-ME) to form fluorescence-labeled products in the stacking process, and the labeled derivatives were then enriched by online stacking. Optimal conditions for the stacking, such as the concentration of the background buffer solution, the matrix of the sample zone (sample solution), and the volume of the sample injection, were investigated and then applied to real sample analysis. Under optimum conditions, the detections were linear in the range of 5.0 nM-2.5 microM with the square of correlation coefficients (R2) of 0.9995 and 0.9992 for GABA and Ala, respectively. Detection limits were found to be 0.7 and 0.8 nM for GABA and Ala, respectively. Tea samples were analyzed with recoveries between 92.33 and 97.87% and between 94.36 and 96.46% for GABA and Ala, respectively. This method is a rapid, convenient, and sensitive process for determining GABA and Ala in complicated matrix samples such as tea samples.
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Affiliation(s)
- Yi-Song Su
- Department of Chemistry, National Chung-Hsing University, and Department of Education and Research, Taichung Veterans General Hospital, Taichung 402, Taiwan
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Abstract
A fluorimetric method was used to determine the o-phthaldialdehyde (OPA) reactivity of amino groups for the assessment of non-enzymatic browning reactions in products with a prolonged shelf-life. The studies were conducted in four commercial infant cereals: wheat-based '7-cereals' and '8-cereals', and gluten-free 'rice cereal' and 'rice-corn cereal'. The cereals were monitored at 28 degrees C for 4 or 16 weeks, or under high water activity (0.65) conditions at 25 degrees C or 55 degrees C for 1, 2, 3 or 4 weeks. OPA reactivity gradually decreased during storage under all temperature, time and water activity conditions, with especially marked losses under conditions of greatest heat intensity and high water activity. According to the present results, the determination of OPA reactivity offers a simple, rapid and reliable method to evaluate non-enzymatic browning.
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Affiliation(s)
- Antonio Ramírez-Jiménez
- Departamento de Nutrición y Bromatología, Facultad de Farmacia, Campus Universitario de Cartuja 18012 Granada, Universidad de Granada, Spain
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Zhu D, Huang S, Gebregeorgis E, McClellan H, Dai W, Miller L, Saul A. Development of a Direct Alhydrogel Formulation Immunoassay (DAFIA). J Immunol Methods 2009; 344:73-8. [PMID: 19328804 PMCID: PMC2712229 DOI: 10.1016/j.jim.2009.03.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Revised: 03/12/2009] [Accepted: 03/18/2009] [Indexed: 11/28/2022]
Abstract
Alhydrogel (aluminum hydroxide) is a widely used adjuvant in the US. Regulatory authorities require that vaccines be tested to determine the antigen content in the final vaccine product. The level of formulated antigen is currently determined in our laboratory by the o-Phthalaldehyde (OPA) fluorescent protein assay, and antigen identity and integrity are determined by Western blot and SDS-PAGE. However, OPA assay is non-specific and only limited to detection of total protein content, and it is often not sensitive enough to detect antigens in low dose formulations. Furthermore, antigens used in identity and integrity tests must be extracted from vaccines using an extraction procedure which is time-consuming and may not completely recover antigens for analysis or may alter the structures of antigens during extraction. The present study developed a Direct Alum Formulation Immunoassay (DAFIA) which was designed to directly (without antigen extraction), accurately, and sensitively determine the antigen content, identity and integrity on alum. The AMA1-C1/Alhydrogel formulation was used as a model vaccine in assay development and validation. The results showed that the DAFIA is highly antigen-specific, accurate (87-100%), sensitive (0.16 microg/ml), reproducible, and simple with a linear detection range of 0.16-10 microg/ml. These results demonstrate that DAFIA is an excellent assay to determine antigen content, identity and integrity of antigens bound to alum and may be used in routine vaccine quality control for testing antigens in Alhydrogel-based vaccines.
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Affiliation(s)
- Daming Zhu
- Malaria Vaccine Development Branch, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD 20852, USA.
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Nishino N, Arey J, Atkinson R. Formation and reactions of 2-formylcinnamaldehyde in the OH radical-initiated reaction of naphthalene. Environ Sci Technol 2009; 43:1349-1353. [PMID: 19350902 DOI: 10.1021/es802477s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
2-Formylcinnamaldehyde [O-HC(O)C6H4CH=CHCHO] is a major product of the OH radical-initiated reaction of naphthalene, the atmospherically most abundant polycyclic aromatic hydrocarbon. Previous studies indicate that 2-formylcinnamaldehyde undergoes photolysis as well as reaction with OH radicals. We have used direct air sampling atmospheric pressure ionization mass spectrometry (API-MS) to monitor 2-formylcinnamaldehyde as its protonated molecular ion during OH radical-initiated reactions of naphthalene. From the time-dependent behavior of the 2-formylcinnamaldehyde signal, ratios of (2-formylcinnamaldehyde removal rate/naphthalene reaction rate) were determined over a range of approximately 3 in (OH radical concentration/ light intensity). With an estimated rate constant for the reaction of OH radicals with 2-formylcinnamaldehyde of 5.3 x 10(-11) cm3 molecule(-1) s(-1), the photolysis rate of 2-formylcinnamaldhyde by blacklamps was determined to be approximately equal to that of NO2. Photolysis of 2-formylcinnamaldehyde will be the dominant loss process in the atmosphere, with an estimated lifetime of 2-formylcinnamaldehyde of approximately 120 s at a solar zenith angle of 30 degrees. Our data were used to re-evaluate the previous 2-formylcinnamaldehyde measurements of Sasaki et al. (Environ. Sci. Technol. 1997, 31, 3173-3179) and derive a 2-formylcinnamaldehyde formation yield from the OH radical reaction of naphthalene in the presence of NO of 56(-10)(+15)%.
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Affiliation(s)
- Noriko Nishino
- Air Pollution Research Center, University of California Riverside, California 92521, USA
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Tang YB, Huang LJ, Li DZ, Zhang QJ, Chen RY, Yu DQ. The synthesis of analogs of shuangkangsu, a novel natural cycloperoxide glucoside from Lonicera japonica Thunb. J Asian Nat Prod Res 2009; 11:172-176. [PMID: 19219731 DOI: 10.1080/10286020802618985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Four novel optically pure cycloperoxide glucosides 9a, 9b, 10a, and 10b, analogs of shuangkangsu--a natural product with unusual skeleton and antivirus activity from the buds of Lonicera japonica Thunb, were firstly synthesized by employing peroxidation and glucosidation reactions from phthalaldehyde or 4,5-dichloro phthalaldehyde and glucose.
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Affiliation(s)
- Yan-Bo Tang
- Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Peking Union Medical College, Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing, China
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Reddy PM, Prasad AVSS, Rohini R, Ravinder V. Catalytic reduction of pralidoxime in pharmaceuticals by macrocyclic Ni(II) compounds derived from orthophthalaldehyde. Spectrochim Acta A Mol Biomol Spectrosc 2008; 70:704-712. [PMID: 18068425 DOI: 10.1016/j.saa.2007.10.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 09/29/2007] [Accepted: 10/15/2007] [Indexed: 05/25/2023]
Abstract
Efficient catalytic method for the reduction of pralidoxime to its amine derivative by macrocyclic Ni(II) compounds has been developed. Ten macrocyclic Schiff base Ni(II) compounds were synthesized via non-template synthesis by treating the corresponding macrocycles with nickel chloride in 1:1 ratio. The resulting compounds were characterized by elemental, IR, (1)H NMR, (13)C NMR, mass, electronic spectra, conductance, magnetic, thermal studies and their structures have been proposed. These compounds were used as catalysts for the reduction of pralidoxime to its amino derivative. The reduced pralidoxime was also characterized by spectral analysis and catalytic cycle has been established. The reduced product was determined spectrophotometrically by treating with ninhydrin reagent and the percent yields were found to be in the range of 75.12-82.36%.
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Fimmen RL, Trouts TD, Richter DD, Vasudevan D. Improved speciation of dissolved organic nitrogen in natural waters: amide hydrolysis with fluorescence derivatization. J Environ Sci (China) 2008; 20:1273-1280. [PMID: 19143355 DOI: 10.1016/s1001-0742(08)62221-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The objective of this study was to improve primary-amine nitrogen (1 degree-N) quantification in dissolved organic matter (DOM) originating from natural waters where inorganic forms of N, which may cause analytical interference, are commonly encountered. Efforts were targeted at elucidating organic-N structural criteria influencing the response of organic amines to known colorimetric and fluorescent reagents and exploring the use of divalent metal-assisted amide hydrolysis in combination with fluorescence analyses. We found that reaction of o-phthaldialdehyde (OPA) with primary amines is significantly influenced by steric factors, whereas fluorescamine (FLU) lacks sensitivity to steric factors and allows for the detection of a larger suite of organic amines, including di- and tri-peptides and sterically hindered 1degree-N. Due to the near quantitative recovery of dissolved peptides with the FLU reagent and lack of analytical response to inorganic nitrogen, we proposed that FLU be utilized for the quantification of primary amine nitrogen. In exploring the application of divalent metal promoted peptide hydrolysis to the analysis of organic forms of nitrogen in DOM, we found that Zn(II) reaction increased the total fraction of organic-N detectable by both OPA and FLU reagents. Zn-hydrolysis improved recovery of organic-N in natural waters from < 5% to 35%. The above method, coupled with standard inorganic-N analyses, allows for enhanced resolution of dissolved organic nitrogen (DON) speciation in natural waters.
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Affiliation(s)
- Ryan L Fimmen
- School of Earth Sciences, The Ohio State University, 125 S. Oval Mall, Columbus, OH 43210, USA.
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Yoshitake M, Nohta H, Ogata S, Todoroki K, Yoshida H, Yoshitake T, Yamaguchi M. Liquid chromatography method for detecting native fluorescent bioamines in urine using post-column derivatization and intramolecular FRET detection. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 858:307-12. [PMID: 17851146 DOI: 10.1016/j.jchromb.2007.08.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 06/18/2007] [Accepted: 08/20/2007] [Indexed: 11/18/2022]
Abstract
Liquid chromatography (LC) with fluorescence detection is described for simultaneous determination of native fluorescent bioamines (indoleamines and catecholamines). This is based on intramolecular fluorescence resonance energy transfer (FRET) in an LC system following post-column derivatization of native fluorescent bioamines' amino groups with o-phthalaldehyde (OPA). OPA fluorescence was achieved through an intramolecular FRET process when the molecules were excited at maximum excitation wavelength of the native fluorescent bioamines. Bioamines separated by reversed-phase LC on ODS column were derivatized with OPA and 2-mercaptoethanol. This method provides sufficient selectivity and sensitivity for the determination of normetanephrine, dopamine, tyrosine, 5-hydroxytryptamine, tryptamine, and tryptophan in healthy human urine without prior sample purification.
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Affiliation(s)
- Makoto Yoshitake
- Faculty of Pharmaceutical Sciences, Fukuoka University, Nanakuma, Johnan, Fukuoka 814-0180, Japan
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Hanczkó R, Jámbor A, Perl A, Molnár-Perl I. Advances in the o-phthalaldehyde derivatizations. J Chromatogr A 2007; 1163:25-42. [PMID: 17606270 DOI: 10.1016/j.chroma.2007.06.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 05/20/2007] [Accepted: 06/08/2007] [Indexed: 11/30/2022]
Abstract
The main aims of this work were (a) to present the characteristics and stability of the o-phthalaldehyde (OPA)-ethanethiol (ET) derivatives of 22 amino acids, including the believed-to-be less stable OPA derivatives providing glycine, gamma-aminobutyric acid, beta-alanine, histidine, ornithine, lysine and the C(1)-C(5) aliphatic amines; (b) to compare the stability properties of the most common amino acids and amines as OPA-ET-fluorenylmethyl chloroformate (FMOC) derivatives to the corresponding ones obtained from OPA reagents containing various (SH)-additives; (c) to show the molar responses of alanine and lysine depending on the OPA reagent's composition; as well as (d) to prove the practical utility of these basic researches, by the simultaneous HPLC separation of 22 amino acids and 15 amines as their OPA-ET-FMOC derivatives. Investigations have been carried out by varying the composition of the reagents, the molar ratios of reactants and the reaction time, applying diode array and fluorescence detections simultaneously. Average reproducibility of quantitations, characterized with the relative standard deviations (RSDs) based on the fluorescence intensities of derivatives, in the order of listing, proved to be 1.2-5.9% for amino acids and 1.1-8.7% for amines. The practical utility of the method is demonstrated by the analysis of the amino acid and amine contents of mouse tissues, with an average reproducibility of 3.5%.
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Affiliation(s)
- R Hanczkó
- Institute of Chemistry, Department of Analytical Chemistry, L. Eötvös University, PO Box 32, H-1518 Budapest 112, Hungary
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Garavito G, Monje MC, Maurel S, Valentin A, Nepveu F, Deharo E. A non-radiolabeled heme–GSH interaction test for the screening of antimalarial compounds. Exp Parasitol 2007; 116:311-3. [PMID: 17336296 DOI: 10.1016/j.exppara.2007.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Revised: 12/23/2006] [Accepted: 01/11/2007] [Indexed: 11/26/2022]
Abstract
Intraerythrocytic Plasmodium produces large amounts of toxic heme during the digestion of hemoglobin, a parasite specific pathway. Heme is then partially biocristallized into hemozoin and mostly detoxified by reduced glutathione. We proposed an in vitro micro assay to test the ability of drugs to inhibit heme-glutathione dependent degradation. As glutathione and o-phthalaldehyde form a fluorescent adduct, we followed the extinction of the fluorescent signal when heme was added with or without antimalarial compounds. In this assay, 50 microM of amodiaquine, arthemether, chloroquine, methylene blue, mefloquine and quinine inhibited the interaction between glutathione (50 microM) and heme (50 microM), while atovaquone did not. Consequently, this test could detect drugs that can inhibit heme-GSH degradation in a fast, simple and specific way, making it suitable for high throughput screening of potential antimalarials.
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Affiliation(s)
- Giovanny Garavito
- Departamento de Farmacia, Facultad de Ciencias, Universidad Nacional de Colombia, Carrera 30 45-03, Bogotá, DC, Colombia
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Go K, Garcia R, Villarreal FJ. Fluorescent method for detection of cleaved collagens using O-phthaldialdehyde (OPA). ACTA ACUST UNITED AC 2007; 70:878-82. [PMID: 17573117 PMCID: PMC2836792 DOI: 10.1016/j.jbbm.2007.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 05/17/2007] [Accepted: 05/18/2007] [Indexed: 11/17/2022]
Abstract
Analysis of collagen degradation remains an important but cumbersome task. Traditional methods with dansyl chloride derivatization of collagen have been used to quantify collagen damage. Fluorescent labeling reagents have been developed that offer advantages such as greater solubility in water and low background emission. One such reagent is o-phthalaldehyde (OPA). In this study, we used OPA as a means of detecting small amounts of degraded collagen. Collagen samples isolated from skin or heart were used for OPA conjugation to exposed amino termini ("opalation"). Experiments utilizing small samples aliquoted in microtiter plates were performed to evaluate effects of increasing concentrations of OPA, varying concentrations of collagen, and effects of matrix metalloproteinase (MMP) digestion. Results indicate that within 10 min of reaction, OPA can be used to detect relative differences in cleaved vs. uncleaved collagen from skin or heart. Heart samples obtained from regions of high MMP activity correlated with increased OPA fluorescence relative to tissue with lower MMP activity. On the basis of these results, we conclude that OPA has valuable practical advantages for analytical use in detecting cleaved collagen in small tissue samples.
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Affiliation(s)
| | | | - Francisco J. Villarreal
- *Correspondence to: Francisco Villarreal M.D. Ph.D., UCSD Cardiology, 9500 Gilman Dr. 0613J, BSB 2004, La Jolla, CA 92093, tel (858) 534-3630, fax (858) 534-0522,
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Salem N, Andreescu S, Kulla E, Zuman P. Existence and Reactivity of Three Forms of Orthophthalaldehyde in Aqueous Solutions. Polarographic, Voltammetric, and Spectrophotometric Study. J Phys Chem A 2007; 111:4658-70. [PMID: 17488102 DOI: 10.1021/jp071151s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Orthophthalaldehyde (1,2-dicarboxaldehyde) (OPA) forms in the presence of a strong nucleophile with amino acids isoindole derivatives. The reaction is used in fluorometric determination of amino acids. The mechanism of these processes is not understood. OPA is present in aqueous solutions in three forms: unhydrated (I(a)), monohydrated acyclic (I(b)), and cyclic hemiacetal (I(c)). The absence of data for the molar absorptivities of these forms, together with overlap of their absorption bands, limits the application of spectrophotometry. Measurement of polarographic limiting currents of forms I(a) and I(b) enables determination of equilibrium constants K1 (formation of I(b)) and K2 (for the ring formation). The presence of these forms was supported by 1H NMR and 13C NMR. The rate of hydration of OPA is general-acid-base-catalyzed, but that of dehydration shows only specific-acid-base catalysis. The rate of hydration is controlled by general-acid-base-catalyzed addition of water to I(a). The rate of dehydration depends on the opening of the ring in I(c), which is specific-acid-base-catalyzed. At pH > 10 OPA undergoes a complex set of acid-base reactions (Scheme 3). The presence of polarographic anodic waves and oxidation on the gold electrode indicates the importance of the presence of a geminal diol form (II(a)). Establishment of equilibria among the three forms of OPA together with reactions at pH > 10 has to be considered in elucidating the reaction scheme of procedures using OPA as a reagent in the determination of amino acids.
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Affiliation(s)
- Nuha Salem
- Department of Chemistry, Clarkson University, Potsdam, New York 13699-5810, USA
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Hapuarachchi S, Aspinwall CA. Design, characterization, and utilization of a fast fluorescence derivatization reaction utilizingo-phthaldialdehyde coupled with fluorescent thiols. Electrophoresis 2007; 28:1100-6. [PMID: 17311246 DOI: 10.1002/elps.200600567] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have developed a chemical derivatization scheme for primary amines that couples the fast kinetic properties of o-phthaldialdehyde (OPA) with the photophysical properties of visible, high quantum yield, fluorescent dyes. In this reaction, OPA is used as a cross-linking reagent in the labeling reaction of primary amines in the presence of a fluorescent thiol, 5-((2-(and-3)-S-(acetylmercapto)succinoyl)amino)fluorescein (SAMSA fluorescein), thereby incorporating fluorescein (epsilon = 78 000 M(-1), quantum yield of 0.98) into the isoindole product. Detection is based on excitation and emission of the incorporated fluorescein using the 488 nm laser line of an Ar(+) laser rather than the UV-excited isoindole, thereby eliminating the UV light sources for detection. Using this method, we have quantitatively labeled biologically important primary amines in less than 10 s. Detection limits for analysis of glutamate, glycine, GABA, and taurine were less than 2 nM. We present the characterization of OPA/SAMSA-F reaction and the potential utility of the derivatization reaction for dynamic chemical monitoring of biologically relevant analytes using CE.
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Devall AJ, Blake R, Langman N, Smith CGS, Richards DA, Whitehead KJ. Monolithic column-based reversed-phase liquid chromatography separation for amino acid assay in microdialysates and cerebral spinal fluid. J Chromatogr B Analyt Technol Biomed Life Sci 2007; 848:323-8. [PMID: 17101306 DOI: 10.1016/j.jchromb.2006.10.049] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 10/27/2006] [Accepted: 10/27/2006] [Indexed: 11/22/2022]
Abstract
The development of a HPLC method using a monolithic C18 column is described using fluorescence detection for the assay of 21 amino acids and related substances with derivatisation using ortho-phthaldialdehyde (OPA) in the presence of 3-mercaptopropionic acid (3-MPA). The method employs a tertiary gradient and has a run time of 24 min. Linearity (r2) for each amino acid was found to be greater than 0.99 up to a 10 microM concentration; reproducibility across all analyses (relative standard deviation (R.S.D.)) was between 0.97 and 6.7% and limit of detection (LOD) between 30 and 300 fmol on column. This method has been applied to the analysis of amino acids in both spinal microdialysis and cerebral spinal fluid samples.
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Affiliation(s)
- A J Devall
- Pain Signalling Group, Department of Pharmacology, Division of Neuroscience, The Medical School, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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Nemati M, Valizadeh H, Ansarin M, Ghaderi F. Development of a simple and sensitive high-performance liquid chromatography method for determination of glucosamine in pharmaceutical formulations. J AOAC Int 2007; 90:354-7. [PMID: 17474504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
A column high-performance liquid chromatography (HPLC) method was developed for the determination of glucosamine in dosage forms. Glucosamine was derivatized by addition of a solution containing orthophthaldialdehyde. The HPLC separation was achieved on a Spherimage 80 ODS2 column (250 x 4 mm id, 5 microm particle size) using an isocratic mobile phase containing phosphate buffer-methanol (90 + 10, v/v, pH 6.50) and methanol-tetrahydrofuran (97 + 3, v/v) in proportions of 85 + 15 at a flow rate of 1 mL/min, followed by fluorescence detection. The method was validated for specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantitation (LOQ). The detector response for glucosamine HCI was linear over the concentration range of 0.1-20 microg/mL with a correlation coefficient of 0.9980. The accuracy was between 99.4 and 100.8%. The LOD and the LOQ were 0.009 and 0.027 microg/mL, respectively. The method was applied to determination of glucosamine in solid dosage forms.
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Affiliation(s)
- Mahboob Nemati
- Tabriz University of Medical Sciences, Faculty of Pharmacy, Department of Pharmacognosy and Food Science, Iran.
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Abstract
Zn-proline (5 mol%) performs as a novel water-soluble and recyclable Lewis acid catalyst for the selective synthesis of 1,2-disubstituted benzimidazoles from wide range of substituted o-phenylenediamines and aldehydes in moderate to excellent isolated yields (42-92%) using water as solvent at ambient temperature.
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Affiliation(s)
- Varala Ravi
- Indian Institute of Chemical Technology, Hyderabad, India
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