1
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Ducrozet F, Sebastian A, Garcia Villavicencio CJ, Ptasinska S, Sicard-Roselli C. Quantifying hydroxyl radicals generated by a low-temperature plasma using coumarin: methodology and precautions. Phys Chem Chem Phys 2024; 26:8651-8657. [PMID: 38436422 DOI: 10.1039/d4cp00040d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
The detection and quantification of hydroxyl radicals (HO˙) generated by low-temperature plasmas (LTPs) are crucial for understanding their role in diverse applications of plasma radiation. In this study, the formation of HO˙ in the irradiated aqueous phase is investigated at various plasma parameters, by probing them indirectly using the coumarin molecule. We propose a quantification methodology for these radicals, combining spectrophotometry to study the coumarin reaction with hydroxyl radicals and fluorimetry to evaluate the formation yield of the hydroxylated product, 7-hydroxycoumarin. Additionally, we thoroughly examine and discuss the impact of pH on this quantification process. This approach enhances our comprehension of HO˙ formation during LTP irradiation, adding valuable insights to plasma's biological applications.
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Affiliation(s)
- Florent Ducrozet
- Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Amal Sebastian
- Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA.
- Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Cecilia Julieta Garcia Villavicencio
- Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA.
- Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Sylwia Ptasinska
- Radiation Laboratory, University of Notre Dame, Notre Dame, IN 46556, USA.
- Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Cécile Sicard-Roselli
- Institut de Chimie Physique, UMR 8000, CNRS, Université Paris-Saclay, 91405 Orsay, France.
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2
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Knoor LH, Hoogewerf LP, Jonker IB, Doty EA, Du Laney GR, Blankespoor RL, Muyskens MA. Spectral properties and modeling of knightletin, a novel aminocoumarin with intramolecular hydrogen bonding. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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3
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Nowak PM, Biel I, Kózka G, Klag M, Woźniakiewicz M. Influence of pH measurement inaccuracy on the values of acidity constant determined on the basis of electrophoretic and thermophoretic data. Microchem J 2022. [DOI: 10.1016/j.microc.2022.107689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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4
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AuNP-/rGO-/GCE-based molecular imprinted electrochemical sensor for rapid and sensitive detection of coumarin. CHEMICAL PAPERS 2022. [DOI: 10.1007/s11696-022-02139-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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5
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Albishri A, Cabot JM, Fuguet E, Rosés M. Determination of the aqueous pK a of very insoluble drugs by capillary electrophoresis: Internal standards for methanol-water extrapolation. J Chromatogr A 2021; 1665:462795. [PMID: 35042141 DOI: 10.1016/j.chroma.2021.462795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 10/19/2022]
Abstract
A fast determination of acidity constants (pKa) of very insoluble drugs has become a necessity in drug discovery process because it often produces molecules that are highly lipophilic and sparingly soluble in water. In this work the high throughput internal standard capillary electrophoresis (IS-CE) method has been adapted to the determination of pKa of water insoluble compounds by measurement in methanol/aqueous buffer mixtures. For this purpose, the reference pKa values for a set of 46 acid-base compounds of varied structure (internal standards) have been established in methanol-water mixtures at several solvent composition levels (with a maximum of 40% methanol). The IS-CE method has been successfully applied to seven test drugs of different chemical nature with intrinsic solubilities lower than 10-6 M. pKa values have been determined at different methanol/aqueous buffer compositions and afterwards Yasuda-Shedlovsky extrapolation method has been applied to obtain the aqueous pKa. The obtained results have successfully been compared to literature ones obtained by other methods. It is concluded that the IS-CE method allows the determination of aqueous pKa values using low proportions of methanol, becoming then more accurate in the extrapolation procedure than other reference methods.
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Affiliation(s)
- Abdulkarim Albishri
- Departament de Química Analítica and Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11 E, Barcelona 08028, Spain
| | - Joan M Cabot
- Leitat Technology Center, Innovació 2, Barcelona 08225, Spain.
| | - Elisabet Fuguet
- Departament de Química Analítica and Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11 E, Barcelona 08028, Spain; Serra Húnter Programm, Generalitat de Catalunya, Barcelona, Spain
| | - Martí Rosés
- Departament de Química Analítica and Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11 E, Barcelona 08028, Spain.
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6
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Knoor ALH, Du Laney GR, Jonker IB, Hoogewerf LP, Tu Y, Pham HT, Yoo J, Muyskens MA. Aesculetin Exhibits Strong Fluorescent Photoacid Character. J Fluoresc 2021; 32:307-318. [PMID: 34787776 DOI: 10.1007/s10895-021-02842-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/18/2021] [Indexed: 11/24/2022]
Abstract
Coumarins are bioactive molecules that often serve as defenses in plant and animal systems, and understanding their fundamental behavior is essential for understanding their bioactivity. Aesculetin (6,7-dihydroxycoumarin) has recently attracted attention due to its ability to act as an antioxidant, but little is known about its photophysical properties. The fluorescence lifetimes of its neutral and anion form in water are 19 ± 2 ps and 2.3 ± 0.1 ns, respectively. Assuming the short lifetime of the neutral is determined by ESPT, we estimate kPT ~ 5 × 1010 s-1. Using steady-state and time-resolved fluorescence spectroscopy, we determine its ground and excited-state [Formula: see text] to be 7.3 and -1, respectively, making it one of the strongest photoacids of the natural coumarins. Aesculetin exhibits a strong pH dependence of the relative fluorescence quantum yield becoming much more fluorescent above [Formula: see text]. The aesculetin anion [Formula: see text] slightly photobasic character. We also report that aesculetin forms a fluorescent catechol-like complex with boric acid, and this complex has a [Formula: see text] of 5.6.
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Affiliation(s)
| | | | - Isaac B Jonker
- Calvin University, 3201 Burton St SE, Grand Rapids, MI, 49546, USA
| | - Liam P Hoogewerf
- Calvin University, 3201 Burton St SE, Grand Rapids, MI, 49546, USA
| | - Yukun Tu
- Calvin University, 3201 Burton St SE, Grand Rapids, MI, 49546, USA
| | - Hunter T Pham
- Calvin University, 3201 Burton St SE, Grand Rapids, MI, 49546, USA
| | - Joy Yoo
- Calvin University, 3201 Burton St SE, Grand Rapids, MI, 49546, USA
| | - Mark A Muyskens
- Calvin University, 3201 Burton St SE, Grand Rapids, MI, 49546, USA.
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7
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Bideh NZ, Mashhadi N, Taylor KE, Biswas N. Elimination of selected heterocyclic aromatic emerging contaminants from water using soybean peroxidase. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:37570-37579. [PMID: 33715130 DOI: 10.1007/s11356-021-13403-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Widespread occurrence of various heterocyclic aromatic compounds is reported in concentrations from 1 to 20 μg/L in surface and groundwater as well as influents and effluents of wastewater treatment plants around the world. These so-called emerging contaminants and their metabolites can cause adverse effects on the environment and humans, even at very low concentration, hence raised environmental concerns. In this study, feasibility of soybean peroxidase-catalyzed removal of three selected heterocyclic aromatics from water was investigated, including sensitivity to the most important operational conditions, pH (range 3.6-9.0), H2O2 concentration (range 0.10-1.50 mM), and enzyme activity (range 0.001-5.0 U/mL). 3-Hydroxycoumarin and 2-aminobenzoxaozle were found to be substrates for the enzyme, having ≥95% and 45% removal efficiency with most effective pHs of 7.0 and 6.0, respectively. Time course study was also conducted to determine the initial first-order rate constants and half-lives; half-lives normalized for enzyme activity (0.0257 and 452 min for the respective substrates) are compared with those of 21 other compounds reactive with soybean peroxidase. High-resolution mass spectrometry was employed to characterize the plausible oligomerization products of enzymatic treatment, which revealed formation of dimers and trimers of the two substrates.
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Affiliation(s)
- Negin Ziayee Bideh
- Department of Civil and Environmental Engineering, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - Neda Mashhadi
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
| | - Keith E Taylor
- Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada.
| | - Nihar Biswas
- Department of Civil and Environmental Engineering, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4, Canada
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Nowak PM, Mitoraj M, Sagan F, Wietecha-Posłuszny R. Differentiation of isomeric metabolites of carbamazepine based on acid-base properties; Experimental vs theoretical approach. J Chromatogr A 2021; 1651:462275. [PMID: 34090055 DOI: 10.1016/j.chroma.2021.462275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 01/01/2023]
Abstract
Metabolism of carbamazepine is complex and leads to the three isomeric derivatives whose occurrence is dependent on the type of sample material. Their unambiguous differentiation is overall important. In this work, the qualitative analysis of 2-hydroxycarbamazepine, 3-hydroxycrbamazepine and carbamazepine-10,11-epoxide was attempted for the first time using capillary zone electrophoresis, based on the models linking electrophoretic mobility with pKa value determining the acidity of the hydroxyl groups. For this purpose, pKa values were determined using electrophoretic and theoretical methods, and then the compliance of the obtained mobility models with the measured values was analyzed. Despite the slight difference in acidity (0.3-0.4 pH unit), the obtained results prove that the correct identification of the metabolites under consideration, and reliable prediction of the selectivity of their separation, are possible on the basis of experimentally determined pKa values, even with highly simplified methods assuming the lack of certain data. However, it is important to choose the optimal pH value, which should be close to pKa. On the other hand, worse results were obtained for the theoretically determined mobilities, which differed significantly from the experimental values. An attempt was also made to explain the acidity of hydroxycarbamazepines and the associated thermodynamic parameters - deprotonation enthalpy and entropy, with respect to their structure. The lack of intramolecular hydrogen bonds and the significant contribution of entropic effects stabilizing the protonated form seems to be significant. The higher pKa value for CBZ-2-OH probably results from the stronger effect of the energetically unfavorable organization of solvent dipoles due to ionization.
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Affiliation(s)
- Paweł Mateusz Nowak
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Analytical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland.
| | - Mariusz Mitoraj
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Theoretical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland
| | - Filip Sagan
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Theoretical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland
| | - Renata Wietecha-Posłuszny
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Analytical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland
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9
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Enantioseparation of warfarin derivatives on molecularly imprinted polymers for (S)- and (R)-chlorowarfarin. J Chromatogr A 2021; 1641:461995. [PMID: 33611112 DOI: 10.1016/j.chroma.2021.461995] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 11/22/2022]
Abstract
Monodisperse molecularly imprinted polymers (MIPs) for warfarin (WF), 4'-chlorowarfarin (CWF), (S)-CWF and (R)-CWF (MIPWF, MIPCWF, MIP(S)-CWF and MIP(R)-CWF, respectively) were prepared using 4-vinylpyridine (4-VPY) and ethylene glycol dimethacrylate (EDMA) as a functional monomer and a crosslinker, respectively, by multi-step swelling and polymerization. The molar ratio of a template molecule, 4-VPY to EDMA was 6:18:25 or 4:18:25. The retention and molecular recognition properties of MIPWF and MIPCWF were evaluated using a mixture of sodium phosphate buffer or ammonium formate and acetonitrile in reversed-phase LC. WF and CWF on these MIPs gave the maximal retentions at mobile phase pH 7, and those retentions were decreased with an increase of acetonitrile content. The retention and imprinting factors were in the order of WF < CWF < 4'-bromowarfarin (BWF) on MIPWF and MIPCWF in neutral mobile phases. On the other hands, in acidic mobile phases the retention factors were in the same order with those in neutral mobile phases, while the imprinting factors of WF and CWF were higher on the respective MIPs. These results suggest that ionic or hydrogen bonding interactions, hydrophobic interactions and π-π interactions could work for the retention and molecular recognition of WF, CWF and BWF on these MIPs in a reversed-phase mode. Furthermore, MIP(S)-CWF and MIP(R)-CWF could separate WF, CWF and BWF enantiomers in acidic mobile phases.
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10
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Šolínová V, Brynda J, Šícha V, Holub J, Grűner B, Kašička V. Determination of acidity constants, ionic mobilities, and hydrodynamic radii of carborane-based inhibitors of carbonic anhydrases by capillary electrophoresis. Electrophoresis 2021; 42:910-919. [PMID: 33405254 DOI: 10.1002/elps.202000298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/08/2020] [Accepted: 12/31/2020] [Indexed: 12/17/2022]
Abstract
Capillary electrophoresis (CE) has been applied for determination of the thermodynamic acidity constants (pKa ) of the sulfamidoalkyl and sulfonamidoalkyl groups, the actual and limiting ionic mobilities and hydrodynamic radii of important compounds, eight carborane-based inhibitors of carbonic anhydrases, which are potential new anticancer drugs. Two types of carboranes were investigated, (i) icosahedral cobalt bis(dicarbollide)(1-) ion with sulfamidoalkyl moieties, and (ii) 7,8-nido-dicarbaundecaborate with sulfonamidoalkyl side chains. First, the mixed acidity constants, pKa mix , of the sulfamidoalkyl and sulfonamidoalkyl groups of the above carboranes and their actual ionic mobilities were determined by nonlinear regression analysis of the pH dependences of their effective electrophoretic mobility measured by capillary electrophoresis in the pH range 8.00-12.25, at constant ionic strength (25 mM), and constant temperature (25°C). Second, the pKa mix were recalculated to the thermodynamic pKa s using the Debye-Hückel theory. The sulfamidoalkyl and sulfonamidoalkyl groups were found to be very weakly acidic with the pKa s in the range 10.78-11.45 depending on the type of carborane cluster and on the position and length of the alkyl chain on the carborane scaffold. These pKa s were in a good agreement with the pKa s (10.67-11.27) obtained by new program AnglerFish (freeware at https://echmet.natur.cuni.cz), which provides thermodynamic pKa s and limiting ionic mobilities directly from the raw CE data. The absolute values of the limiting ionic mobilities of univalent and divalent carborane anions were in the range 18.3-27.8 TU (Tiselius unit, 1 × 10-9 m2 /Vs), and 36.4-45.9 TU, respectively. The Stokes hydrodynamic radii of univalent and divalent carborane anions varied in the range 0.34-0.52 and 0.42-0.52 nm, respectively.
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Affiliation(s)
- Veronika Šolínová
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague 6, Czechia
| | - Jiří Brynda
- Institute of Molecular Genetics of the Czech Academy of Sciences, Prague 4, Czechia
| | - Václav Šícha
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež, Czechia
| | - Josef Holub
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež, Czechia
| | - Bohumír Grűner
- Institute of Inorganic Chemistry of the Czech Academy of Sciences, Husinec-Řež, Czechia
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague 6, Czechia
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11
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Computational studies of acidities of some hydroxycoumarins. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.113008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Shalaby AA, Mohamed AA. Determination of acid dissociation constants of Alizarin Red S, Methyl Orange, Bromothymol Blue and Bromophenol Blue using a digital camera. RSC Adv 2020; 10:11311-11316. [PMID: 35495332 PMCID: PMC9050617 DOI: 10.1039/c9ra10568a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/13/2020] [Indexed: 11/21/2022] Open
Abstract
Acid dissociation constants (pKa) are important parameters for the characterization of organic and inorganic compounds. They play a crucial role in different physical, chemical, and biological studies. Herein, we introduce a new approach for the determination of acid dissociation constant based on digital image analysis using a low-cost, precise, accurate, sensitive, and portable home-made, camera-based platform. Digital images of Alizarin Red S, Bromophenol Blue, Bromothymol Blue, and Methyl Orange solutions were captured at various pH values. The captured images were analysed to obtain the RGB (Red, Green, and Blue) colour intensities that are used to calculate the RGB colour absorbances. The pKa values were calculated from the RGB colour absorbance–pH relationship using graphical and mathematical methods, and with the aid of DATAN software. For the four studied dyes, the results obtained from digital image analysis were in excellent agreement with the data of sophisticated spectrophotometers and the previously reported literature data. Acid dissociation constants (pKa) are important parameters for the characterization of organic and inorganic compounds.![]()
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Affiliation(s)
- Ahmed A Shalaby
- Department of Chemistry, Faculty of Science, Ain Shams University Abbassia Cairo-11566 Egypt +202 24831836 +201001578849
| | - Ashraf A Mohamed
- Department of Chemistry, Faculty of Science, Ain Shams University Abbassia Cairo-11566 Egypt +202 24831836 +201001578849
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Acidity constant of pH indicators in the supramolecular systems studied by two CE-based methods compared using the RGB additive color model. Anal Bioanal Chem 2019; 412:577-588. [PMID: 31838556 DOI: 10.1007/s00216-019-02289-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/31/2019] [Accepted: 11/14/2019] [Indexed: 02/07/2023]
Abstract
Acid-base properties of methyl orange, bromocresol green, bromophenol blue, and bromothymol blue were thoroughly investigated in the past due to their application as colorimetric pH indicators. However, it is still unknown how these properties change upon the supramolecular host-guest interactions. Owing to the growing interest in using supramolecular host-guest interactions to reach expected modification of various physicochemical properties of guests, we decided to address this question in the present article. We estimated the shifts of pKa values induced by diverse hosts (cyclodextrins, cucurbiturils, calixarenes, micelles, and serum albumin) and performed a thermodynamic analysis of the selected systems. To make a deeper insight, we confronted the aforementioned dyes with the other kinds of molecules studied by us in the past. In overall, the results obtained demonstrate a large multiplicity of possible pKa behaviors, their poor predictability, and the existence of subtle structure-acidity relationships. In addition, we observed three thermodynamically different mechanisms of pKa alteration. Therefore, more studies are needed to bring closer the promising perspective of a programmable acidity's tuning. Our methodology was based on capillary electrophoresis (CE) applied in two parallel variants: a classical method based on the fitting of a nonlinear function, and an alternative two-value method (TVM), which requires over twice less measurements to estimate pKa. To identify the optimal approach for further studies, both methods were comprehensively compared and discussed based on the RGB additive color model, a user-friendly scale that integrates three primary aspects of an analytical method: analytical performance, green chemistry, and practicality.
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14
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Sosa DO, Almaraz K, Amézquita-Valencia M. Regioselective Synthesis of 4,5-Dihydro-6 H
-oxepino[3,2- c
]chromene-2,6(3 H
)-diones through Palladium-Catalyzed Intramolecular Alkoxycarbonylation of 3-Allyl-4-hydroxycoumarins. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- D. Oliver Sosa
- Instituto de Química, Ciudad Universitaria, Ciudad de México; Universidad Nacional Autónoma de México; 04510 México
| | - Karla Almaraz
- Instituto de Química, Ciudad Universitaria, Ciudad de México; Universidad Nacional Autónoma de México; 04510 México
| | - Manuel Amézquita-Valencia
- Instituto de Química, Ciudad Universitaria, Ciudad de México; Universidad Nacional Autónoma de México; 04510 México
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15
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Cyclodextrin-induced acidity modification of substituted cathinones studied by capillary electrophoresis supported by density functional theory calculations. J Chromatogr A 2018; 1580:142-151. [DOI: 10.1016/j.chroma.2018.10.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/08/2018] [Accepted: 10/16/2018] [Indexed: 11/22/2022]
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16
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Woźniakiewicz M, Nowak PM, Gołąb M, Adamowicz P, Kała M, Kościelniak P. Acidity of substituted cathinones studied by capillary electrophoresis using the standard and fast alternative approaches. Talanta 2018; 180:193-198. [DOI: 10.1016/j.talanta.2017.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/08/2017] [Accepted: 12/11/2017] [Indexed: 11/26/2022]
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17
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Nowak PM, Woźniakiewicz M, Kościelniak P. Flow variation as a factor determining repeatability of the internal standard-based qualitative and quantitative analyses by capillary electrophoresis. J Chromatogr A 2018; 1548:92-99. [PMID: 29559267 DOI: 10.1016/j.chroma.2018.03.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/08/2018] [Accepted: 03/13/2018] [Indexed: 11/30/2022]
Abstract
The use of migration times and peak areas referred to another sample component - internal standard, brings many benefits in improving reliability of capillary electrophoresis. However, it is quite commonly overlooked that despite relative migration time and peak area ratio are more stable than the absolute values upon alteration in the flow rate, some shift should always be expected. The present work offers a new look at this analytically-important issue. We have derived a simple model allowing to estimate the magnitude of error for the selected pair of molecules of known mobilities upon the given flow alteration. Then, we have confronted the theoretical predictions with the experimental results obtained for the model sample separated in various flow conditions reached by the external pressure manipulation, including several internal standards of different mobilities. A good agreement has been obtained, pointing out that the magnitude of error may be large even for the seemingly "good" internal standards. Several potentially useful means have been tested to address this issue: the use of electrophoretic mobilities and electrophoretic mobility ratios instead migration times in the qualitative analysis, and performing time-correction of peak area ratios, or alternatively, transformation of electropherograms from the time-related scale into the electrophoretic mobility-related scale in the quantitative analysis. We have also considered some additional factors. The results may be of interest for all users dealing with the development and optimization of analytical methods using capillary electrophoresis.
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Affiliation(s)
- Paweł Mateusz Nowak
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Analytical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland.
| | - Michał Woźniakiewicz
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Analytical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland
| | - Paweł Kościelniak
- Jagiellonian University in Kraków, Faculty of Chemistry, Department of Analytical Chemistry, Gronostajowa St. 2, 30-387 Kraków, Poland
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18
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Thermodynamics of acid-base dissociation of several cathinones and 1‐phenylethylamine, studied by an accurate capillary electrophoresis method free from the Joule heating impact. J Chromatogr A 2018; 1539:78-86. [DOI: 10.1016/j.chroma.2018.01.047] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 12/12/2022]
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19
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Nakamura Y, Masumoto S, Kubo A, Matsunaga H, Haginaka J. Preparation of molecularly imprinted polymers for warfarin and coumachlor by multi-step swelling and polymerization method and their imprinting effects. J Chromatogr A 2017; 1516:71-78. [DOI: 10.1016/j.chroma.2017.08.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/24/2017] [Accepted: 08/05/2017] [Indexed: 10/19/2022]
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20
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Matyjaszczyk K, Kolonko M, Gonciarz-Dytman A, Oszczapowicz I, Łukawska M, Jawień W, Chlopicki S, Walczak M. Effects of structural modification of the daunosamine moiety of anthracycline antibiotics on pKa values determined by capillary zone electrophoresis. J Chromatogr B Analyt Technol Biomed Life Sci 2017; 1060:44-52. [DOI: 10.1016/j.jchromb.2017.04.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 04/20/2017] [Accepted: 04/22/2017] [Indexed: 01/14/2023]
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21
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Shi F, Liu J. Simultaneous determination of the lipophilicity and dissociation constants of dialkyl phosphinic acids by negligible depletion hollow fiber membrane-protected liquid-phase microextraction. J Chromatogr A 2017; 1507:11-17. [PMID: 28599859 DOI: 10.1016/j.chroma.2017.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 11/17/2022]
Abstract
Determination of the physicochemical properties, especially the lipophilicity (expressed as the logarithm of distribution coefficient, log D) and dissociation constant (pKa), is of great importance in the early stage of environmental risk assessment for an ionizable compound without these data. Currently, the log D and pKa values of dialkyl phosphinic acids (DPAs), the environmental hydrolysates of aluminum dialkyl phosphinates (ADPs) that is one class of emerging phosphorus-containing flame retardants, are not available. In this study, the log D and pKa values of three DPAs including methylethylphosphinic acid (MEPA), diethylphosphinic acid (DEPA) and methylcyclohexyl phosphinic acid (MHPA), were simultaneously determined by negligible depletion hollow fiber supported liquid phase microextraction (nd-HF-LPME) followed by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The pKa and log D of DPAs were determined by curve-fitting the experimental data with equations derived on the basis of the Henderson-Hasselbalch equation and compared with model calculated data. For MEPA, DEPA and MHPA, the pKa values were close and around 3, but the log Ds were strongly pH-dependent with values from -5.01 to 1.01. The log KOW of the neutral form (logKOW,HA) and ionic form (logKOW,A) were in the range of -0.67-1.02 and -3.86--1.33, respectively. The experimentally determined pKa values were highly in good agreement with ACD/pKa predicted values and the measured log KOW,HA values were closely related to KOWWIN calculated ones, suggesting ACD/pKa and KOWWIN are good alternative methods to estimate pKa and log KOW of DPAs, respectively. As far as we know, this is the first report on the pKa and log D data for DPAs, which are fundamental for the product design and evaluating the environmental behavior and effects of DPAs and ADPs.
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Affiliation(s)
- Fengqiong Shi
- State Key Laboratory of Environmental and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingfu Liu
- State Key Laboratory of Environmental and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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22
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Nowak PM, Woźniakiewicz M, Gładysz M, Janus M, Kościelniak P. Improving repeatability of capillary electrophoresis-a critical comparison of ten different capillary inner surfaces and three criteria of peak identification. Anal Bioanal Chem 2017; 409:4383-4393. [PMID: 28484810 PMCID: PMC5486911 DOI: 10.1007/s00216-017-0382-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 04/18/2017] [Accepted: 04/25/2017] [Indexed: 01/30/2023]
Abstract
A poor repeatability of migration times caused by the fluctuations of electroosmotic flow (EOF) is an inherent weakness of capillary electrophoresis. Most researchers endeavor to prevent this problem using relative migration times or various capillary coatings which are expensive and not easy in comparison. Herein, we present an original approach to this problem: we apply a model sample designed to induce significant EOF instability, in order to critically compare ten capillary types with different physicochemical characteristics. Moreover, we accompany capillary modification with the evaluation of various criteria of peak identification: migration time, migration times ratio, and electrophoretic mobility. Our results show a great effectiveness of a dynamic coating in the stabilization of migration times, with the average RSD(%) value reduced from 3.5% (bare silica capillary) down to 0.5%. The good outcomes were also obtained for the surfactant-modified silica and amine capillaries. For the capillaries exhibiting significant instability of EOF, electrophoretic mobility turned out to be a more universal and reliable criterion of peak identification than relative migration time. It can be explained by an intrinsic dependency of migration times ratio on EOF change, which should always be considered during the selection of an internal standard.
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Affiliation(s)
- Paweł Mateusz Nowak
- Faculty of Chemistry, Department of Analytical Chemistry, Jagiellonian University in Kraków, Ingardena St. 3, 30-060, Kraków, Poland.
| | - Michał Woźniakiewicz
- Faculty of Chemistry, Department of Analytical Chemistry, Jagiellonian University in Kraków, Ingardena St. 3, 30-060, Kraków, Poland
| | - Marta Gładysz
- Faculty of Chemistry, Department of Analytical Chemistry, Jagiellonian University in Kraków, Ingardena St. 3, 30-060, Kraków, Poland
| | - Magdalena Janus
- Faculty of Chemistry, Department of Analytical Chemistry, Jagiellonian University in Kraków, Ingardena St. 3, 30-060, Kraków, Poland
| | - Paweł Kościelniak
- Faculty of Chemistry, Department of Analytical Chemistry, Jagiellonian University in Kraków, Ingardena St. 3, 30-060, Kraków, Poland
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23
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Separation of 20 coumarin derivatives using the capillary electrophoresis method optimized by a series of Doehlert experimental designs. Talanta 2017; 167:714-724. [DOI: 10.1016/j.talanta.2017.02.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/04/2017] [Accepted: 02/07/2017] [Indexed: 02/07/2023]
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24
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Nowak PM, Sagan F, Mitoraj MP. Origin of Remarkably Different Acidity of Hydroxycoumarins—Joint Experimental and Theoretical Studies. J Phys Chem B 2017; 121:4554-4561. [DOI: 10.1021/acs.jpcb.7b01849] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paweł Mateusz Nowak
- Faculty
of Chemistry, Department of Analytical Chemistry, Jagiellonian University in Kraków, Ingardena 3, 30-060 Kraków, Poland
| | - Filip Sagan
- Faculty
of Chemistry, Department of Theoretical Chemistry, Jagiellonian University in Kraków, Ingardena 3, 30-060 Kraków, Poland
| | - Mariusz Paweł Mitoraj
- Faculty
of Chemistry, Department of Theoretical Chemistry, Jagiellonian University in Kraków, Ingardena 3, 30-060 Kraków, Poland
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25
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Nowak PM, Śpiewak K, Woźniakiewicz M, Kościelniak P. Minimizing the impact of Joule heating as a prerequisite for the reliable analysis of metal‐protein complexes by capillary electrophoresis. J Chromatogr A 2017; 1495:83-87. [DOI: 10.1016/j.chroma.2017.03.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/14/2017] [Accepted: 03/16/2017] [Indexed: 11/29/2022]
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26
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Enhancing effectiveness of capillary electrophoresis as an analytical tool in the supramolecular acidity modification. Anal Bioanal Chem 2017; 409:3633-3643. [PMID: 28341986 PMCID: PMC5406438 DOI: 10.1007/s00216-017-0305-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/01/2017] [Accepted: 03/08/2017] [Indexed: 12/15/2022]
Abstract
A strategic modification of acidity (pKa values) by the non-covalent host-guest interactions is one of the most promising concepts in current supramolecular chemistry. This work is aimed at enhancing the effectiveness of capillary electrophoresis (CE) in determination of pKa shifts caused by such interactions and their thermal dependencies crucial in a deep thermodynamic description. We show how to (i) minimize the systematic errors related to Joule heating, (ii) minimize the influence of a voltage ramp time, (iii) speed up pKa shift identification and estimation, (iv) interpret thermal effects related to two overlapped dynamic equilibria, and (v) determine pKa shifts by an alternative spectrophotometric method (CE-DAD). The proposed solutions were implemented to examine the supramolecular pKa shifts of several coumarin derivatives, caused by a variety of structurally different cyclodextrins. It was revealed that a specific host substitution pattern determines the magnitude of apparent pKa shifts. Accordingly, heptakis(2,6-di-O-methyl)-β-cyclodextrin induces the much stronger shifts than both non-methylated-β-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin applied at the same concentration. We also show that insofar as the complexation of 4-hydroxycoumarin and its derivative (coumatetralyl) are similarly exothermic, the thermal effects accompanying the deprotonation process are remarkably different for both molecules. The pKa shift induced by complexation with calixarene was also for the first time determined by a CE method. These observations throw a new light on the background of acidity modification and confirm the applicability of CE as an analytical tool.
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27
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Nowak PM, Woźniakiewicz M, Kościelniak P. Seven Approaches to Elimination of the Inherent Systematic Errors in Determination of Electrophoretic Mobility by Capillary Electrophoresis. Anal Chem 2017; 89:3630-3638. [PMID: 28207231 DOI: 10.1021/acs.analchem.6b05036] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Electrophoretic mobility is a basic parameter that describes the electromigration of an ionized particle, which is used in many fields of analytical and physicochemical science. Its determination by capillary electrophoresis (CE), using a routine method, is intrinsically affected by the generation of Joule heating, entailing a drop in viscosity and possible alteration of the degree of ionization, and also by other commonly overlooked effects: axial electric field distortion and voltage ramping. The objective of this work was to provide the first theoretical overview and experimental comparison of all accessible methods that could be used to prevent these sources of inaccuracy. We have discussed seven independent approaches: (i) extrapolation of mobility to the zero power, (ii) initial buffer resistance-based correction, (iii) rational cooling adjustment, (iv) elimination of the nonthermostated capillary part, (v) inter/extrapolation to the nominal temperature, (vi) internal standard-based correction, and (vii) simple recalculation based on the temperature rise. Two methodologies (v and vi) have been proposed for the first time. Furthermore, we have shown how some approaches can be further developed, obtaining several novel and more sophisticated methods, which are also included in the comparison. Our investigation will help researchers to choose the optimal approach. We have also demonstrated for the first time how to measure the independent impact of four different effects. The outcomes reveal the compensatory character of some phenomena and explain the highly diverse and unpredictable magnitude of the total errors. The use of a correction method seems crucial for ensuring the high reliability of CE-based analyses.
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Affiliation(s)
- Paweł Mateusz Nowak
- Department of Analytical Chemistry, Jagiellonian University in Kraków, Faculty of Chemistry , Ingardena St. 3, 30-060 Kraków, Poland
| | - Michał Woźniakiewicz
- Department of Analytical Chemistry, Jagiellonian University in Kraków, Faculty of Chemistry , Ingardena St. 3, 30-060 Kraków, Poland
| | - Paweł Kościelniak
- Department of Analytical Chemistry, Jagiellonian University in Kraków, Faculty of Chemistry , Ingardena St. 3, 30-060 Kraków, Poland
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28
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Nowak PM, Woźniakiewicz M, Michalik M, Fiedor L, Kościelniak P. Capillary coating as an important factor in optimization of the off-line and on-line MEKC assays of the highly hydrophobic enzyme chlorophyllase. Anal Bioanal Chem 2017; 409:1493-1501. [PMID: 27888314 PMCID: PMC5306352 DOI: 10.1007/s00216-016-0097-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 11/07/2016] [Accepted: 11/11/2016] [Indexed: 12/15/2022]
Abstract
The choice between bare and coated capillaries is a key decision in the development and use of any methods based on capillary electrophoresis. In this work several permanently and dynamically coated capillaries were successfully implemented in a previously developed micellar electrokinetic chromatography (MEKC) assay of the plant membrane enzyme chlorophyllase. The results obtained demonstrate the rationale behind the use of capillary coating, which is crucial for successful optimization of both the off-line mode and the on-line/electrophoretically mediated microanalysis assay mode. The application of an amine permanently coated capillary (eCAP) is a simple way to significantly increase the repeatability of migration times and peak areas, and to ensure a strong electroosmotic flow that considerably decreases the overall analysis time. A dynamic coating (CEofix) allows one to apply an on-line incubation to control the reaction progress inside the capillary, and to increase the signal-to-noise ratio and peak efficiency. The dynamic coating is possible with use of both the normally applied uncoated silica capillary and the precoated amine capillary, which ensures more repeatable migration times. The strong points of the uncoated silica capillary are its attractive price and wide range of pH that can be applied. The characteristics presented may simplify the choice of capillary modification, especially in the case of hydrophobic analytes, MEKC-based separations, and other enzymatic assays.
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Affiliation(s)
- Paweł Mateusz Nowak
- Faculty of Chemistry, Jagiellonian University in Kraków, Ingardena 3, 30-060, Kraków, Poland.
| | - Michał Woźniakiewicz
- Faculty of Chemistry, Jagiellonian University in Kraków, Ingardena 3, 30-060, Kraków, Poland
| | - Maciej Michalik
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Kraków, Gronostajowa 7, 30-387, Kraków, Poland
| | - Leszek Fiedor
- Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University in Kraków, Gronostajowa 7, 30-387, Kraków, Poland
| | - Paweł Kościelniak
- Faculty of Chemistry, Jagiellonian University in Kraków, Ingardena 3, 30-060, Kraków, Poland
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29
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Investigation of the acid-base and electromigration properties of 5‐azacytosine derivatives using capillary electrophoresis and density functional theory calculations. J Chromatogr A 2017; 1479:185-193. [DOI: 10.1016/j.chroma.2016.11.058] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/25/2016] [Accepted: 11/28/2016] [Indexed: 11/20/2022]
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30
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Li T, Liu B, Duan S, Cui M. Fluorescence spectra, fluorescence quantum yield and dissociation constant of sarafloxacin. LUMINESCENCE 2016; 32:545-548. [DOI: 10.1002/bio.3211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 07/22/2016] [Accepted: 08/08/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Tongtong Li
- College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province; Hebei University; Baoding Hebei Province People's Republic of China
| | - Baosheng Liu
- College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province; Hebei University; Baoding Hebei Province People's Republic of China
| | - Shaotong Duan
- College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province; Hebei University; Baoding Hebei Province People's Republic of China
| | - Mengmeng Cui
- College of Chemistry and Environmental Science, Key Laboratory of Analytical Science and Technology of Hebei Province; Hebei University; Baoding Hebei Province People's Republic of China
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