1
|
Zhao J, Yang X, Leng X, Wang C, Schipper D. Rapid and reliable ratiometric fluorescence detection of isoquercitrin based on a high-nuclearity Zn(II)-Nd(III) nanomolecular sensor. Talanta 2024; 275:126170. [PMID: 38703478 DOI: 10.1016/j.talanta.2024.126170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 04/22/2024] [Accepted: 04/25/2024] [Indexed: 05/06/2024]
Abstract
Rapid and quantitative detection of isoquercitrin (Isq) has been attracting much attention due to its outstanding pharmacological and physiological activities. Herein, an interesting 48-metal Zn(II)-Nd(III) nanocluster (1, molecular sizes 1.3 × 2.8 × 3.1 nm) with salen-type Schiff base ligand was constructed as molecular sensor for the luminescence detection of Isq. 1 exhibits visible ligand-centered emission and NIR luminescence of Nd(III), and shows ratiometric fluorescence response to Isq with high sensitivity even in the presence of other interferences. The fluorescence sensing behavior can be expressed by a second-order equation I1060nm/I480nm = A*[Isq]2 + B*[Isq] + C, which is used to quantitatively analyze the Isq concentrations in DMF and FCS. The LODs to Isq for the ligand-centered and lanthanide emissions of 1 in DMF are 0.21 μM and 0.11 nM, respectively. The quenching of the ligand-centered emission of 1 caused by Isq is attributed to the competitive absorption of light energy and "inner effect", while, the luminescence enhancement is due to the "antenna effect".
Collapse
Affiliation(s)
- Jinni Zhao
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, 325035, China
| | - Xiaoping Yang
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, 325035, China.
| | - Xilong Leng
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, 325035, China
| | - Chengri Wang
- College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou, 325035, China
| | - Desmond Schipper
- The University of Texas at Austin, Department of Chemistry and Biochemistry, 1 University Station A5300, Austin, TX, 78712, United States
| |
Collapse
|
2
|
Graf HG, Rudisch BM, Ude L, Müller L, Huhn C. Picomolar detection limits for glyphosate by two-dimensional column-coupled isotachophoresis/capillary zone electrophoresis-mass spectrometry. J Sep Sci 2022; 45:3887-3899. [PMID: 35998068 DOI: 10.1002/jssc.202200519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 11/09/2022]
Abstract
Capillary electrophoresis-mass spectrometry often lacks sufficient limits of detection for trace substances in the environment due to its low loadability. To overcome this problem, we conducted a feasibility study for column-coupling isotachophoresis to capillary electrophoresis-mass spectrometry. The first dimension isotachophoresis preconcentrated the analytes. The column-coupling of both dimensions was achieved by a hybrid capillary microfluidic chip setup. Reliable analyte transfer by voltage switching was enabled by an in-chip capacitively coupled contactless conductivity detector placed around the channel of the common section between two T-shaped crossings in the chip connecting both dimensions. This eliminated the need to calculate the moment of analyte transfer. A commercial capillary electrophoresis-mass spectrometry instrument with easily installable adaptations operated the setup. Prior to coupling isotachophoresis with capillary zone electrophoresis-mass spectrometry, both dimensions were optimized individually by simulations and verified experimentally. Both dimensions were able to stack/separate all degradation products of glyphosate, the most important herbicide applied worldwide. The first dimension isotachophoresis also removed phosphate, which is a critical matrix component in many environmental samples. Enrichment and separation of glyphosate and its main degradation product aminomethylphosphonic acid by the 2D setup provided an excellent limit of detection of 150 pM (25 ng/L) for glyphosate. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Hannes Georg Graf
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | | | - Lukas Ude
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Linda Müller
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Carolin Huhn
- Institute of Physical and Theoretical Chemistry, Eberhard Karls Universität Tübingen, Tübingen, Germany
| |
Collapse
|
3
|
Pinheiro RGR, Pinheiro M, Neves AR. Nanotechnology Innovations to Enhance the Therapeutic Efficacy of Quercetin. NANOMATERIALS 2021; 11:nano11102658. [PMID: 34685098 PMCID: PMC8539325 DOI: 10.3390/nano11102658] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 12/12/2022]
Abstract
Quercetin is a flavonol present in many vegetables and fruits. Generally, quercetin can be found in aglycone and glycoside forms, mainly in leaves. The absorption of this compound occurs in the large and small intestine, where it suffers glucuronidation, sulfidation, and methylation to improve hydrophilicity. After metabolization, which occurs mainly in the gut, it is distributed throughout the whole organism and is excreted by feces, urine, and exhalation of carbon dioxide. Despite its in vitro cytotoxicity effects, in vivo studies with animal models ensure its safety. This compound can protect against cancer, cardiovascular diseases, chronic inflammation, oxidative stress, and neurodegenerative diseases due to its radical scavenging and anti-inflammatory properties. However, its poor bioavailability dampens the potential beneficial effects of this flavonoid. In that sense, many types of nanocarriers have been developed to improve quercetin solubility, as well as to design tissue-specific delivery systems. All these studies manage to improve the bioavailability of quercetin, allowing it to increase its concentration in the desired places. Collectively, quercetin can become a promising compound if nanotechnology is employed as a tool to enhance its therapeutic efficacy.
Collapse
Affiliation(s)
- Rúben G. R. Pinheiro
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal; (R.G.R.P.); (M.P.)
| | - Marina Pinheiro
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal; (R.G.R.P.); (M.P.)
| | - Ana Rute Neves
- LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal; (R.G.R.P.); (M.P.)
- CQM—Centro de Química da Madeira, Universidade da Madeira, Campus da Penteada, 9020-105 Funchal, Portugal
- Correspondence:
| |
Collapse
|
4
|
Red-emitting BSA-stabilized copper nanoclusters acted as a sensitive probe for fluorescence sensing and visual imaging detection of rutin. Talanta 2018; 178:1006-1010. [DOI: 10.1016/j.talanta.2017.08.102] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/23/2017] [Accepted: 08/30/2017] [Indexed: 12/31/2022]
|
5
|
Topcagic A, Cavar Zeljkovic S, Karalija E, Galijasevic S, Sofic E. Evaluation of phenolic profile, enzyme inhibitory and antimicrobial activities of Nigella sativa L. seed extracts. Bosn J Basic Med Sci 2017; 17:286-294. [PMID: 28590231 DOI: 10.17305/bjbms.2017.2049] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 01/24/2023] Open
Abstract
Black cumin (Nigella sativa L. [N.sativa]) seed extracts demonstrated numerous beneficial biological effects including, among others, antidiabetic, anticancer, immunomodulatory, antimicrobial, anti-inflammatory, antihypertensive, and antioxidant activity. To better understand the phytochemical composition of N. sativa seeds, methanol seed extracts were analyzed for phenolic acid and flavonoid content. Furthermore, we tested N. sativa methanol, n-hexane, and aqueous seed extracts for their inhibitory activity against butyrylcholinesterase (BChE) and catalase (CAT) as well as for antimicrobial activity against several bacterial and a yeast strains. The phenolic content of N. sativa was analyzed using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The inhibition of BChE was assessed by modified Ellman's method, and the inhibition of CAT was determined by monitoring hydrogen peroxide consumption. The extracts were tested against Bacillus subtilis, Staphylococcus aureus, Salmonella enterica, and Escherichia coli using the agar diffusion method. The UHPLC-MS/MS method allowed the identification and quantification of 23 phenolic compounds within 15 minutes. The major components found in N. sativa seed extract were sinapinic acid (7.22 ± 0.73 µg/mg) as a phenolic acid and kaempferol (11.74 ± 0.92 µg/mg) as a flavonoid. All extracts showed inhibitory activity against BChE, with methanol seed extract demonstrating the highest inhibitory activity (inhibitory concentration 50% [IC50] 79.11 ± 6.06 µg/ml). The methanol seed extract also showed strong inhibitory activity against CAT with an IC50 value of 6.61 ± 0.27 µg/ml. Finally, the methanol extract exhibited considerable inhibitory activity against the tested microbial strains. Overall, this is the first study to investigate the ability of black cumin seed extracts to inhibit CAT. Our results indicate that N. sativa seed can be considered as an effective inhibitor of CAT activity.
Collapse
Affiliation(s)
- Anela Topcagic
- Department of Chemistry, Faculty of Science, University of Sarajevo, Sarajevo, Bosnia and Herzegovina.
| | | | | | | | | |
Collapse
|
6
|
Liu Z, Xue Q, Guo Y. Sensitive electrochemical detection of rutin and isoquercitrin based on SH-β-cyclodextrin functionalized graphene-palladium nanoparticles. Biosens Bioelectron 2017; 89:444-452. [DOI: 10.1016/j.bios.2016.04.056] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Revised: 04/15/2016] [Accepted: 04/18/2016] [Indexed: 01/09/2023]
|
7
|
Helmja K, Vaher M, Püssa T, Orav A, Viitak A, Levandi T, Kaljurand M. Variation in the composition of the essential oils, phenolic compounds and mineral elements ofHypericum perforatumL. growing in Estonia. Nat Prod Res 2011; 25:496-510. [DOI: 10.1080/14786411003792165] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
8
|
Pantůčková P, Křivánková L. Analysis of 5-methyltetrahydrofolate in human blood, serum and urine by on-line coupling of capillary isotachophoresis and zone electrophoresis. Electrophoresis 2010; 31:3391-9. [DOI: 10.1002/elps.201000193] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
9
|
Honegr J, Šafra J, Polášek M, Pospíšilová M. Large-Volume Sample Stacking with Polarity Switching in CE for Determination of Natural Polyphenols in Plant Extracts. Chromatographia 2010. [DOI: 10.1365/s10337-010-1752-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
10
|
Kurzawa M. Determination of Quercetin and Rutin in Selected Herbs and Pharmaceutical Preparations. ANAL LETT 2010. [DOI: 10.1080/00032710903491070] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
11
|
Biesaga M, Pyrzynska K. Analytical Procedures for Determination of Quercetin and its Glycosides in Plant Material. Crit Rev Anal Chem 2009. [DOI: 10.1080/10408340902820718] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
12
|
Strašík S, Lučaníková M, Kaniansky D. Enhancement of analyte detectability in isotachophoresis exploiting spectrophotometric diode-array detection with chemometric data processing. J Sep Sci 2008; 31:3755-64. [DOI: 10.1002/jssc.200800381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
13
|
Nováková M, Křivánková L. Determination of ethyl glucuronide in human serum by hyphenation of capillary isotachophoresis and zone electrophoresis. Electrophoresis 2008; 29:1694-700. [DOI: 10.1002/elps.200700663] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
14
|
Stalikas CD. Extraction, separation, and detection methods for phenolic acids and flavonoids. J Sep Sci 2008; 30:3268-95. [PMID: 18069740 DOI: 10.1002/jssc.200700261] [Citation(s) in RCA: 446] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The impetus for developing analytical methods for phenolic compounds in natural products has proved to be multifaceted. Hundreds of publications on the analysis of this category of compounds have appeared over the past two decades. Traditional and more advanced techniques have come to prominence for sample preparation, separation, detection, and identification. This review provides an updated and extensive overview of methods and their applications in natural product matrices and samples of biological origin. In addition, it critically appraises recent developments and trends, and provides selected representative bibliographic examples.
Collapse
|
15
|
Simpson SL, Quirino JP, Terabe S. On-line sample preconcentration in capillary electrophoresis. J Chromatogr A 2008; 1184:504-41. [DOI: 10.1016/j.chroma.2007.11.001] [Citation(s) in RCA: 269] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2007] [Revised: 10/30/2007] [Accepted: 11/01/2007] [Indexed: 02/06/2023]
|
16
|
Yu LS, Xu XQ, Huang L, Ling JM, Chen GN. Separation and determination of flavonoids using microemulsion EKC with electrochemical detection. Electrophoresis 2008; 29:726-33. [DOI: 10.1002/elps.200700140] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
17
|
Nör C, Bernardi APM, Haas JS, Schripsema J, Rech SB, Von Poser GL. Phenolic Constituents of Hypericum Flowers. Nat Prod Commun 2008. [DOI: 10.1177/1934578x0800300227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Species of Hypericum accumulate phenolic compounds with the phloroglucinol substitution pattern, and there are many reports of such substances isolated from the aerial parts of the plants. In this study, flowers of plants grown in south Brazil were analyzed by means of HPLC, verifying the presence of benzopyrans in H. polyanthemum and dimeric phloroglucinol derivatives in H. caprifoliatum, H. connatum, H. myrianthum and H. polyanthemum. All flowers presented flavonoids, mainly quercetin derivatives, whereas hypericin and analogues were not detected.
Collapse
Affiliation(s)
- Carolina Nör
- Programa de Pós Graduação em Ciências Farmacêuticas, UFRGS, Av. Ipiranga, 2752, Porto Alegre, RS, Brazil, 90610-000
| | - Ana Paula Machado Bernardi
- Programa de Pós Graduação em Ciências Farmacêuticas, UFRGS, Av. Ipiranga, 2752, Porto Alegre, RS, Brazil, 90610-000
| | - Juliana Schulte Haas
- Programa de Pós Graduação em Ciências Farmacêuticas, UFRGS, Av. Ipiranga, 2752, Porto Alegre, RS, Brazil, 90610-000
| | - Jan Schripsema
- Setor de Química de Produtos Naturais, LCQUI/CCT, Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000, Campos dos Goytacazes, RJ, Brazil, 28015-620
| | - Sandra Beatriz Rech
- Programa de Pós Graduação em Ciências Farmacêuticas, UFRGS, Av. Ipiranga, 2752, Porto Alegre, RS, Brazil, 90610-000
| | - Gilsane Lino Von Poser
- Programa de Pós Graduação em Ciências Farmacêuticas, UFRGS, Av. Ipiranga, 2752, Porto Alegre, RS, Brazil, 90610-000
| |
Collapse
|
18
|
Pantůcková P, Urbánek M, Krivánková L. Determination of iodide in samples with complex matrices by hyphenation of capillary isotachophoresis and zone electrophoresis. Electrophoresis 2007; 28:3777-85. [PMID: 17893937 DOI: 10.1002/elps.200700189] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A method has been developed for the determination of iodide in mineral water, seawater, cooking salt, serum, and urine based on hyphenation of capillary ITP and zone electrophoresis. A commercially available instrumentation for capillary ITP with column-switching system was used. ITP served for removal of chloride present in the analyzed samples in a ratio of 10(6)-10(7):1 to iodide, zone electrophoresis was used for evaluation. Isotachophoretic separation proceeded in a capillary made of fluorinated ethylene-propylene copolymer of 0.8 mm id and 90 mm total length to the bifurcation point filled with a leading electrolyte (LE) composed of 8 mM HCl + 16 mM beta-alanine (beta-Ala) + 10% PVP + 2.86 mM N(2)H(4)x2HCl, pH 3.2; and a terminating electrolyte composed of 8 mM H(3)PO(4) + 16 mM beta-Ala + 10% PVP + 5 mM N(2)H(4), pH 3.85 for all the matrices except seawater. For ITP of seawater the LE consisted of 50 mM HCl + 100 mM beta-Ala + 10% PVP + 2.86 mM N(2)H(4)x2HCl, pH 3.52. Distance of conductivity detector from the injection point and bifurcation point was 52 and 38 mm, respectively. Zone electrophoresis was performed in a capillary made of fused silica of 0.3 mm id and 160 mm total length filled with LE from isotachophoretic step. LODs reached for all matrices were 2-3x10(-8) M concentration (2.5-4 microg/L) enabled monitoring of iodide in all analyzed samples with RSD 0.4-9.3%. Estimated concentrations of iodide in individual matrices were 10(-6)-10(-8) M.
Collapse
Affiliation(s)
- Pavla Pantůcková
- Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | | | | |
Collapse
|
19
|
Safra J, Pospísilová M, Honegr J, Spilková J. Determination of selected antioxidants in Melissae herba by isotachophoresis and capillary zone electrophoresis in the column-coupling configuration. J Chromatogr A 2007; 1171:124-32. [PMID: 17920611 DOI: 10.1016/j.chroma.2007.09.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Revised: 09/06/2007] [Accepted: 09/12/2007] [Indexed: 11/16/2022]
Abstract
A method utilising isotachophoresis and capillary zone electrophoresis in the column coupling configuration with UV detection at 320 nm was developed for separation and determination of five phenolic acids (rosmarinic, p-coumaric, ferulic, caffeic and chlorogenic) and flavonoid quercitrin in a methanolic extract of Melissae herba. The proposed method has been validated with correlation coefficients from 0.9842 to 0.9988, RSD values between 0.39% and 0.83% for migration times and between 0.40% and 2.05% for peak areas.
Collapse
Affiliation(s)
- Jirí Safra
- Department of Analytical Chemistry, Charles University in Prague, Faculty of Pharmacy, Hradec Králové, Czech Republic.
| | | | | | | |
Collapse
|
20
|
Geng HM, Zhang DQ, Zha JP, Qi JL. Simultaneous HPLC Determination of Five Flavonoids in Flos Inulae. Chromatographia 2007. [DOI: 10.1365/s10337-007-0285-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
21
|
Biesaga M, Stafiej A, Pyrzynska K. Extraction and Hydrolysis Parameters for Determination of Quercetin in Hypericum perforatum. Chromatographia 2007. [DOI: 10.1365/s10337-007-0204-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
22
|
|
23
|
Abstract
ITP has been attracting constant attention for many years due to its principal capability to concentrate trace analytes by several orders of magnitude. In the current capillary format, it is able to concentrate trace analytes diluted to several microliters of an original sample into concentrated zones having volumes in the range of picoliters. Due to this reason, ITP holds an important position in many current multistage and multidimensional separation schemes. This article links up previous reviews on the topic and summarizes the progress of analytical capillary ITP since 2002. Almost 100 papers are reviewed that include methodological novelties, instrumental aspects, and analytical applications. Papers using ITP and/or isotachophoretic principles as part of multistage and/or multidimensional separation schemes are also included.
Collapse
Affiliation(s)
- Petr Gebauer
- Institute of Analytical Chemistry, Academy of Sciences of the Czech Republic, Brno, Czech Republic
| | | | | |
Collapse
|
24
|
Li P, Li SP, Wang YT. Optimization of CZE for analysis of phytochemical bioactive compounds. Electrophoresis 2006; 27:4808-19. [PMID: 17136720 DOI: 10.1002/elps.200600219] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Advantages of CZE such as high efficiency, low cost, short analysis time, and easy implementation result in its wide applications for analysis of phytochemical bioactive compounds (e.g. flavonoids, alkaloids, terpenoids, phenolic acid, saponins, anthraquinones and coumarins). However, several aspects, including sample preparation, separation, and detection have significant effects on CZE analysis. Therefore, optimization of these procedures is necessary for development of the method. In this review, sample preparation such as extraction method and preconcentration, separation factors including buffer type, concentration and pH, additives, voltage and temperature, as well as detection, e.g. direct and indirect UV detection, LIF and MS were discussed for optimization of CZE analysis on phytochemical bioactive compounds. The optimized strategies were also reviewed.
Collapse
Affiliation(s)
- Peng Li
- Institute of Chinese Medical Sciences, University of Macau, Taipa, Macau, China
| | | | | |
Collapse
|
25
|
Ma B, Zhou X, Wang G, Huang H, Dai Z, Qin J, Lin B. Integrated isotachophoretic preconcentration with zone electrophoresis separation on a quartz microchip for UV detection of flavonoids. Electrophoresis 2006; 27:4904-9. [PMID: 17117378 DOI: 10.1002/elps.200600392] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A quartz microchip integrated isotachophoretic (ITP) preconcentration with zone electrophoresis (ZE) separation was fabricated using a novel multi-point pressure method featured in normal temperature and lower pressure during bonding process. ITP followed by subsequential ZE of two flavonoids, quercetin and isorhamnetin on the microchip was performed consecutively on the homemade microfluidic workstation with UV detection, resulting in a decreased detectable concentration of 32-fold, compared to the ZE mode only, and their detection limits decreased down to 0.2 microg/mL and 1.2 microg/mL, respectively.
Collapse
Affiliation(s)
- Bo Ma
- Dalian Institute of Chemical Physics, Graduate School of Chinese Academy of Sciences, Dalian, PR China
| | | | | | | | | | | | | |
Collapse
|
26
|
Hamoudová R, Pospísilová M, Spilková J. Analysis of selected constituents in methanolic extracts ofHypericum perforatum collected in different localities by capillary ITP-CZE. Electrophoresis 2006; 27:4820-6. [PMID: 17136721 DOI: 10.1002/elps.200600193] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The on-line combination of CZE with capillary ITP (ITP-CZE) was used for the separation and quantification of selected flavonoids and phenolic acids in Hypericum perforatum leaves and flowers collected in six different localities in Slovakia. The leading electrolyte in the ITP preseparation step was 10 mM HCl with Tris as counterion (pH* 7.2). The terminating electrolyte was 50 mM boric acid of pH* 8.2 (adjusted with barium hydroxide). The BGE in the electrophoretic step contained 25 mM beta-hydroxy-4-morpholinopropanesulfonic acid (MOPSO), 50 mM Tris, 65 mM boric acid, pH* 8.3. The content of methanol in all electrolytes was 20% v/v. The total time of the analysis (including the preseparation step) was approximately 35 min. The rectilinear calibration ranges were between 0.125 and 5.0 microg/mL with kaempferol as internal standard. The correlation coefficients ranged between 0.9912 (for quercitrin and chlorogenic acid) and 0.9988 (for isoquercitrin). The RSD values are between 0.86 and 7.78% (n = 6) when determining rutin and quercetin (4 microg/mL). The optimized method was employed for the assay of flavonoids in medicinal plant extract of different collections of Hypericum perforatum haulm. The variability of the content of the active components depending on the place of collection was confirmed.
Collapse
Affiliation(s)
- Rafífa Hamoudová
- Department of Analytical Chemistry, Charles University, Faculty of Pharmacy, Hradec Králové, Czech Republic.
| | | | | |
Collapse
|
27
|
Petr J, Maier V, Horáková J, Sevcík J, Stránský Z. Capillary isotachophoresis from the student point of view – images and the reality. J Sep Sci 2006; 29:2705-15. [PMID: 17305231 DOI: 10.1002/jssc.200600249] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A review of some fundamental aspects of ITP from the student point of view, imaginations of some basic facts and laws, use of ITP, and the recent trends are presented. The results of theoretical computations of ITP separation processes are added for comparison of imaginations with the exact mathematical description.
Collapse
Affiliation(s)
- Jan Petr
- Department of Analytical Chemistrý, Palackỳ University, Trída Svobody 8, Olomouc, Czech Republic.
| | | | | | | | | |
Collapse
|
28
|
Busnel JM, Descroix S, Godfrin D, Hennion MC, Kasicka V, Peltre G. Transient isotachophoresis in carrier ampholyte-based capillary electrophoresis for protein analysis. Electrophoresis 2006; 27:3591-8. [PMID: 16977683 DOI: 10.1002/elps.200600230] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Transient ITP (t-ITP) has been used in carrier ampholyte-based CE (CABCE) to enhance the sensitivity of protein analysis. The characteristics of carrier ampholytes (CAs) narrow pH cuts-based buffers, when used as BGEs in CE are compatible with t-ITP requirements. Indeed, being the sole buffering species of such solutions, CAs impose a pH close to their pI. Thus, in these solutions, the CAs possess low electrophoretic mobility. As a consequence, by adding an ionic component with high electrophoretic mobility either in the studied sample or in the BGE, a t-ITP step can be generated. This has first been demonstrated for protein test mixtures. Then, the combination of t-ITP with CABCE has been applied to study a real sample, the bovine milk.
Collapse
Affiliation(s)
- Jean-Marc Busnel
- Laboratory of Environment and Analytical Chemistry, UMR CNRS 7121, ESPCI, Paris, France.
| | | | | | | | | | | |
Collapse
|
29
|
Šafra J, Pospíšilová M, Spilková J. Determination of Phenolic Acids in Herba Epilobi by ITP–CE in the Column-Coupling Configuration. Chromatographia 2006. [DOI: 10.1365/s10337-006-0837-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
30
|
Dubber MJ, Kanfer I. Application of reverse-flow micellar electrokinetic chromatography for the simultaneous determination of flavonols and terpene trilactones in Ginkgo biloba dosage forms. J Chromatogr A 2006; 1122:266-74. [PMID: 16720026 DOI: 10.1016/j.chroma.2006.04.062] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 04/17/2006] [Accepted: 04/24/2006] [Indexed: 11/28/2022]
Abstract
A reverse-flow micellar electrokinetic chromatographic (RF-MEKC) method was developed for the simultaneous qualitative determination of 10 components consisting of the flavonol glycosides, rutin and quercitrin, the flavonol aglycones, isorhamnetin, kaempferol and quercetin, the terpene trilactones, ginkgolides A, B, C and J and the sesquiterpene, bilobalide. This method was used to fingerprint Ginkgo biloba solid oral dosage forms and validated for the quantitation of the marker compounds, rutin and quercetin in some commercial products. In addition to the usual variables, the influence of some essential background electrolyte (BGE) components such as sodium dodecyl sulphate (SDS) and <beta>-cyclodextrin concentrations were investigated. A polyimide fused-silica square capillary column (75 microm I.D. x 360 microm O.D.) with a total length of 60.0 cm and effective length of 45.0 cm was used for the separation. The final BGE consisted of 20 mM phosphoric acid, 40 mM SDS and 12 mM <beta>-cyclodextrin (pH 2.2) using reverse polarity with a voltage of -17.5 kV. Samples were injected electrokinetically at -5 kV for 3 s for the qualitative analysis and hydrodynamically at 20 mbar for 0.6 s for the quantitative assay. The total run time was 22 min and the limits of detection were 3.13 microg/ml and 1.88 microg/ml for rutin and quercetin, respectively. Fingerprint profiles of the solid oral dosage forms and the results of the quantitative analysis indicated that there were major discrepancies in the marker content between products and illustrates the value of this method for use as a procedure to assess product quality of commercially available Ginkgo biloba products.
Collapse
Affiliation(s)
- M-J Dubber
- Faculty of Pharmacy, Division of Pharmaceutics, Rhodes University, Grahamstown 6139, South Africa
| | | |
Collapse
|
31
|
Edwards EL, Rodrigues JA, Ferreira J, Goodall DM, Rauter AP, Justino J, Thomas-Oates J. Capillary electrophoresis-mass spectrometry characterisation of secondary metabolites from the antihyperglycaemic plantGenista tenera. Electrophoresis 2006; 27:2164-70. [PMID: 16736453 DOI: 10.1002/elps.200500688] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Genista tenera is endemic to the Portuguese island of Madeira, where an infusion of the aerial parts of the plant is used in folk medicine as an antidiabetic agent. Consequently the medicinal properties of the secondary metabolites of this plant have been the subject of an ongoing study. A recently reported LC-MS method using a 100 min separation allowed identification of five flavonoid components in an extract of the aerial parts of this plant. In order to obtain additional information on the range and complexity of the plant's secondary metabolite components a CE-MS method has been developed and applied for the analysis of an extract of G. tenera. Twenty-six different components are distinguished in an analysis time of only 10 min. Results demonstrate that CE-MS/MS rapidly generates data complementary to those obtainable by LC-MS/MS and is particularly suited to the analysis of plant metabolites where concentration is not limiting.
Collapse
Affiliation(s)
- Emma L Edwards
- Department of Chemistry, University of York, Heslington, UK
| | | | | | | | | | | | | |
Collapse
|
32
|
Zu YG, Fu YJ, Liu W, Hou CL, Kong Y. Simultaneous Determination of Four Flavonoids in Pigeonpea [Cajanus cajan (L.) Millsp.] Leaves Using RP-LC-DAD. Chromatographia 2006. [DOI: 10.1365/s10337-006-0784-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
33
|
Jác P, Polásek M, Pospísilová M. Recent trends in the determination of polyphenols by electromigration methods. J Pharm Biomed Anal 2006; 40:805-14. [PMID: 16413729 DOI: 10.1016/j.jpba.2005.12.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 12/06/2005] [Accepted: 12/06/2005] [Indexed: 10/25/2022]
Abstract
An overview mapping recent trends in the determination of polyphenols of natural origin (mostly flavonoids) and their synthetic derivatives by electromigration methods is presented. The overview (covering the period of the recent 5 years and comprising 61 references) is focused on capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) with various detection methods. Techniques comprising on-line pre-separation such as isotachophoresis (ITP)-CZE and flow-injection-CZE, chiral separations and CZE evaluation of antioxidation activity are also discussed.
Collapse
Affiliation(s)
- Pavel Jác
- Charles University, Faculty of Pharmacy, Department of Analytical Chemistry, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | | | | |
Collapse
|
34
|
Xu X, Ye H, Wang W, Chen G. An improved method for the quantitation of flavonoids in Herba Leonuri by capillary electrophoresis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:5853-7. [PMID: 16028965 DOI: 10.1021/jf0504216] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A capillary electrophoresis system coupled with wall-jet amperometric detection was used to determine five flavonoids (kaempferol, rutin, hyperoside, quercitrin, quercetin) in Herba Leonuri. Several important effect factors, such as the pH and concentration of running buffer, separation voltage, injection time, and detection potential, were investigated to acquire the optimum conditions. With 50 mmoL/L Na(2)B(4)O(7)-100 mmoL/L NaH(2)PO(4) buffer (pH=7.50) as the running buffer, the five flavonoids were baseline separated within 15 min in a 60 cm length capillary at a separation voltage of 15 kV. The relationship between peak currents and analyte concentrations was linear over about 2 orders of magnitude, with detection limits (S/N = 3) ranging from 0.03 to 0.08 microg/mL for all analytes. The use of this method for the quantitation of the above flavonoids present in the real sample of Herba Leonuri was reported.
Collapse
Affiliation(s)
- Xueqin Xu
- Department of Chemistry, Fuzhou University, and Central Laboratory, Fujian College of Traditional Chinese Medicine, Fuzhou, Fujian 350002, China
| | | | | | | |
Collapse
|
35
|
Peng Y, Yuan J, Ye J. Determination of Active Components in St. John's Wort (Hypericum Perforatum) by Capillary Electrophoresis with Electrochemical Detection. ELECTROANAL 2005. [DOI: 10.1002/elan.200403219] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
36
|
Xu X, Qi X, Wang W, Chen G. Separation and determination of flavonoids inAgrimonia pilosa Ledeb. by capillary electrophoresis with electrochemical detection. J Sep Sci 2005; 28:647-52. [PMID: 15912734 DOI: 10.1002/jssc.200400095] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Five flavonoids (catechin, hyperoside, quercitrin, quercetin, and rutin) were separated and determined by capillary electrophoresis with electrochemical detection. Effects of several important factors, such as the pH and concentration of running buffer, separation voltage, injection time, and detection potential were investigated to determine the optimum conditions. The five flavonoids were baseline separated within 20 min in a 60 cm length capillary at a separation voltage of 19.5 kV with a running buffer consisting of 60 mmoL/L Na2B4O7 - 120 mmoL/L NaH2PO4 (pH = 8.8). The relationship between peak current and analyte concentration was linear over about two orders of magnitude with detection limits (S/N = 3) ranging from 0.02 to 0.05 microg/mL for all compounds. This method was successfully used to determine the above five flavonoids in Agrimonia pilosa Ledeb. with relatively simple extraction procedures, and the assay results were satisfactory.
Collapse
Affiliation(s)
- Xueqin Xu
- Department of Chemistry, Fuzhou University, Fuzhou, Fujian, 350002, China
| | | | | | | |
Collapse
|
37
|
Chen J, Li SL, Li P, Song Y, Chai XY, Ma DY. Qualitative and quantitative analysis of active flavonoids inFlos Loniceraeby capillary zone electrophoresis coupled with solid-phase extraction. J Sep Sci 2005; 28:365-72. [PMID: 15792251 DOI: 10.1002/jssc.200400024] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Flavonoids are an important bioactive group in the commonly used herbal medicine Flos Lonicerae. A new method of capillary zone electrophoresis (CZE) coupled with solid-phase extraction (SPE) was developed for simultaneous assay of flavonoid aglycones and glycosides in Flos Lonicerae. Optimum CZE separation was achieved with a background electrolyte (BGE) solution consisting of 80 mM boric acid and 20 mM phosphate acid, adjusted to pH 8.1, with 15% acetonitrile (v/v) added, and applying a separation voltage of 28 kV. The SPE method was used for pretreating the complex matrix of botanical materials and good reproducibility was obtained when avicularin was used as internal standard. Linearity of the method was excellent with correlation coefficients (r2) in the range of 0.9995-0.9999 and detection limits were lower than 0.6 microg/mL for the four flavonoids. The obtained recoveries varied between 93 to 104% while the relative standard deviations (RSDs) were below 4.4% (n=3). The developed CZE method was successfully used for the separation of eight flavonoids and the quantification of the four flavonoids in five species of Flos Lonicerae.
Collapse
Affiliation(s)
- Jun Chen
- Key Laboratory of Modern Chinese Medicines, Department of Pharmacognosy, China Pharmaceutical University, Nanjing, People's Republic of China
| | | | | | | | | | | |
Collapse
|
38
|
Coupling continuous flow systems to capillary electrophoresis. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0166-526x(05)45004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
39
|
On-line sample preconcentration techniques in capillary electrophoresis. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/s0166-526x(05)45003-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
40
|
Sun SW, Tseng HM. Improved detection of Coptidis alkaloids by field-amplified sample stacking in capillary electrophoresis. J Pharm Biomed Anal 2004; 36:43-8. [PMID: 15351046 DOI: 10.1016/j.jpba.2004.04.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Revised: 04/17/2004] [Accepted: 04/24/2004] [Indexed: 11/16/2022]
Abstract
To improve the on-line detection of Coptidis alkaloids in capillary electrophoresis the field-amplified sample stacking was studied for them. In this work the peak height enhancements of stacking with hydrodynamic and electrokinetic injections were compared with respect to the conventional sample injection. It was found that the stacking efficiency of electrokinetic injection was more than ten times greater than that of hydrodynamic injection. No peak height enhancement was observed with the pre-injection of a short water plug before sample injection with electrokinetic injection. The concentration limits of detection of berberine, coptisine and palmatine obtained with electrokinetic injection were about 5 ng/ml (ppb), which was approximately 240 times lower than those from conventional sample injections. Baseline separation was also achieved for the main alkaloids. After validation the developed method was applied to determine the quantity of berberine, coptisine and palmatine in a Coptidis Rhizoma sample. The method is simple, rapid and should be able to be used in identification and quantitative evaluation of the crude drugs.
Collapse
Affiliation(s)
- Shao-Wen Sun
- School of Pharmacy, College of Medicine, National Taiwan University, 1, Section 1, Jen-Ai Road, Taipei, Taiwan.
| | | |
Collapse
|
41
|
Szłyk E, Jastrzębska A, Brudka B. Determination of total phosphorus in soya food samples by capillary isotachophoresis (cITP). Talanta 2004; 63:575-80. [DOI: 10.1016/j.talanta.2003.11.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2003] [Revised: 11/03/2003] [Accepted: 11/21/2003] [Indexed: 11/15/2022]
|
42
|
Hamoudová R, Urbánek M, Pospísilová M, Polásek M. Assay of phenolic compounds in red wine by on-line combination of capillary isotachophoresis with capillary zone electrophoresis. J Chromatogr A 2004; 1032:281-7. [PMID: 15065806 DOI: 10.1016/j.chroma.2004.01.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The on-line combination of capillary zone electrophoresis (CZE) with capillary isotachophoresis (ITP) increases significantly the separation capability and sensitivity of capillary electrophoresis. This technique was used for separation and quantification of fourteen selected natural constituents in red wine belonging to flavonoids and phenolic acids. The leading electrolyte (LE) in the ITP pre-separation step was 10 mM HCl of pH* 7.2 with Tris as counterion, the terminating electrolyte (TE) was 50 mM boric acid of pH* 8.2 (adjusted with barium hydroxide). The background electrolyte in the electrophoretic step contained 25 mM beta-hydroxy-4-morpholinopropanesulfonic acid (MOPSO), 50 mM Tris, 15 mM boric acid and 5 mM beta-cyclodextrin of pH* 8.5. The content of methanol in all electrolytes was 20% (v/v). For exact timing of the transfer of isotachophoretically stacked analyte zones into the CZE column and for the control of the residual amount of leading and terminating ITP electrolytes picric acid was used as coloured marker. The R.S.D. values (n = 6) ranged between approximately 0.1% (for 0.25 microg ml(-1) rutin) and approximately 11% (for 0.25 microg ml(-1) of quercitrin). Detection limits were 30 ng mi(-1) for phenolic acids, quercitrin and rutin, 100 ng ml(-1) for quercetin, kaempferol and epicatechin and 250 ng ml(-1) for catechin. A single analysis took 45 min.
Collapse
Affiliation(s)
- Rafífa Hamoudová
- Department of Analytical Chemistry, Faculty of Pharmacy, Charles University, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| | | | | | | |
Collapse
|
43
|
Tolonen A, Uusitalo J. Fast screening method for the analysis of total flavonoid content in plants and foodstuffs by high-performance liquid chromatography/electrospray ionization time-of-flight mass spectrometry with polarity switching. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2004; 18:3113-3122. [PMID: 15565731 DOI: 10.1002/rcm.1736] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) method based on time-of-flight (TOF) MS with polarity switching and continuous exact mass measurement using a LockSpray ion source was developed for fast evaluation of the total flavonoid content in plants and foodstuffs. No complicated sample preparation was needed, but only a dilution of the extracts. A fast generic gradient elution and wide mass range acquisition was used with good sensitivity. The total analysis time was only 23 min. The ion chromatograms for flavonoid compounds were automatically extracted, and the fragmentation patterns obtained using positive ion mode and exact mass data for both polarities were used for the tentative identification of compounds. Software-based automated searching of molecular ions for flavonoids and their glycosides (xylosides/arabinosides, rhamnosides, glucosides/galactosides) from total ion chromatograms was used. The compounds were quantified using quercetin, quercitrin, rutin and kuromanine as external standards and dextromethorphan as an internal standard. The detection limits ranged from 0.01-0.04 microg/mL, while the quantitation ranges obtained were 0.2-10 microg/mL for anthocyanins and 0.2-4 microg/mL for the other flavonoids. The accuracies within these ranges varied between 80-120% and precision was in the range 0-14% (relative standard deviation). Flavonoid contents of two medicinal plants (Hypericum perforatum and Rhodiola rosea), two grape red wines, two orange juices and two green teas were evaluated using the method, and the results obtained were in good agreement with those published previously.
Collapse
Affiliation(s)
- Ari Tolonen
- Novamass Analytical Ltd, P.O. Box 3000, 90014 Oulu, Finland.
| | | |
Collapse
|
44
|
Vreeland WN, Williams SJ, Barron AE, Sassi AP. Tandem isotachophoresis-zone electrophoresis via base-mediated destacking for increased detection sensitivity in microfluidic systems. Anal Chem 2003; 75:3059-65. [PMID: 12964751 DOI: 10.1021/ac0259921] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrophoresis in microfluidic devices is becoming a useful analytical platform for a variety of biological assays. In this report, we present a method that allows for an increased sensitivity of detection of fluorescent molecules in microfluidic electrophoresis devices. This capability is provided by the implementation of a particular buffer system that is designed to initially function in an isotachophoretic (ITP) mode and, then after a controlled amount of electric current has been applied to the system, to transition to a zone electrophoretic mode. In the initial ITP mode, analytes dissolved in a large volume of injected sample are concentrated into a single narrow zone. After application of a sufficient and adjustable amount of electric current, the system switches into a zone electrophoretic mode, where the concentrated analytes are separated according to their electrophoretic mobilities. Application of this tandem ITP-zone electrophoretic strategy to the concentration, separation, and detection of fluorescent reporter molecules in a standard microfluidic device results in an approximately 50-fold increase in detection sensitivity relative to equivalent separations that are obtained with zone electrophoresis alone. Even with very long initial sample plugs (up to 3000 microm), this strategy produces electrophoretic separations with high resolutions and peak efficiencies. This strategy can be implemented to increase detection sensitivity in any standard microfluidic electrophoresis platform and does not require any specialized hardware or microchannel configurations.
Collapse
|
45
|
Kaniansky D, Masár M, Bodor R, Zúborová M, Olvecká E, Jöhnck M, Stanislawski B. Electrophoretic separations on chips with hydrodynamically closed separation systems. Electrophoresis 2003; 24:2208-2227. [PMID: 12858394 DOI: 10.1002/elps.200305474] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This review focuses on capillary electrophoretic separations performed on capillary electrophoresis chips (CE chips) with hydrodynamically closed separation systems in a context with transport processes (electroosmotic flow (EOF)) and hydrodynamic flow (HDF)) that may accompany the separations in these devices. It also reflects some relevant works dealing with conventional CE operating under such hydrodynamic conditions. The use of zone electrophoresis (ZE), isotachophoresis (ITP) and their on-line combination (ITP-ZE) on the single-column and column-coupling CE chips with the closed separation systems and related problems are key topics of the review. Some attention is paid to sample pretreatment in the separations performed on the CE chips. Here, mainly potentialities of the ITP-ZE combination in trace analysis applications of the miniaturized systems are discussed in a broader extent. Links between the ZE separation and detection provide a frame for the discussion of current status of the detection on the CE chips. Analytical applications illustrate potentialities of the CE chips operating with the closed separation systems (suppressed HDF and EOF) to the determination of small ions present in various matrices by ZE, ITP and ITP-ZE.
Collapse
Affiliation(s)
- Dusan Kaniansky
- Department of Analytical Chemistry, Faculty of Science, Comenius University, Bratislava, Slovakia.
| | | | | | | | | | | | | |
Collapse
|
46
|
Current awareness in phytochemical analysis. PHYTOCHEMICAL ANALYSIS : PCA 2002; 13:381-388. [PMID: 12669728 DOI: 10.1002/pca.622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
|