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Soriano-Meseguer S, Fuguet E, Port A, Rosés M. Influence of the acid-base ionization of drugs in their retention in reversed-phase liquid chromatography. Anal Chim Acta 2019; 1078:200-211. [DOI: 10.1016/j.aca.2019.05.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/22/2019] [Accepted: 05/26/2019] [Indexed: 11/26/2022]
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2
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Alvarez-Segura T, Subirats X, Rosés M. Retention-pH profiles of acids and bases in hydrophilic interaction liquid chromatography. Anal Chim Acta 2019; 1050:176-184. [DOI: 10.1016/j.aca.2018.11.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 11/05/2018] [Accepted: 11/09/2018] [Indexed: 11/29/2022]
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3
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Simultaneous optimization of pH and binary organic composition by grid form modeling of the retention behavior in reversed-phase ultra high-performance liquid chromatography. J Pharm Biomed Anal 2017; 146:251-260. [DOI: 10.1016/j.jpba.2017.08.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 08/26/2017] [Accepted: 08/29/2017] [Indexed: 11/20/2022]
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4
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RPLC determination of acid dissociation constants and quantitative estimation for sulfasalazine. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2015. [DOI: 10.1007/s13738-015-0717-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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5
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Kurbanoglu S, Palabiyik BB, Gumustas M, Şanlı S, Uslu B, Ozkan SA. DEVELOPMENT AND VALIDATION OF A STABILITY-INDICATING RP-LC METHOD FOR THE DETERMINATION OF ANTICANCER DRUG EPIRUBICIN IN PHARMACEUTICALS. J LIQ CHROMATOGR R T 2014. [DOI: 10.1080/10826076.2013.803202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sevinc Kurbanoglu
- a Department of Analytical Chemistry, Faculty of Pharmacy , Ankara University , Tandogan , Ankara , Turkey
| | - Burcin Bozal Palabiyik
- a Department of Analytical Chemistry, Faculty of Pharmacy , Ankara University , Tandogan , Ankara , Turkey
| | - Mehmet Gumustas
- a Department of Analytical Chemistry, Faculty of Pharmacy , Ankara University , Tandogan , Ankara , Turkey
- b Department of Chemistry, Faculty of Science and Arts , Hitit University , Corum , Turkey
| | - Senem Şanlı
- c Department of Chemistry, Faculty of Science and Arts , Usak University , Usak , Turkey
| | - Bengi Uslu
- a Department of Analytical Chemistry, Faculty of Pharmacy , Ankara University , Tandogan , Ankara , Turkey
| | - Sibel A. Ozkan
- a Department of Analytical Chemistry, Faculty of Pharmacy , Ankara University , Tandogan , Ankara , Turkey
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6
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Jandera P, Vyňuchalová K, Nečilová K. Combined effects of mobile phase composition and temperature on the retention of phenolic antioxidants on an octylsilica polydentate column. J Chromatogr A 2013; 1317:49-58. [DOI: 10.1016/j.chroma.2013.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 07/29/2013] [Accepted: 08/02/2013] [Indexed: 10/26/2022]
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7
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Shaaban H, Górecki T. Fast ultrahigh performance liquid chromatographic method for the simultaneous determination of 25 emerging contaminants in surface water and wastewater samples using superficially porous sub-3 μm particles as an alternative to fully porous sub-2μm particles. Talanta 2012; 100:80-9. [DOI: 10.1016/j.talanta.2012.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/07/2012] [Accepted: 08/08/2012] [Indexed: 11/29/2022]
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8
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Li X. Improved pyrogallol autoxidation method: a reliable and cheap superoxide-scavenging assay suitable for all antioxidants. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2012; 60:6418-24. [PMID: 22656066 DOI: 10.1021/jf204970r] [Citation(s) in RCA: 214] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The original pyrogallol (1,2,3-trihydroxybenzene) method, which was developed specifically for superoxide dismutase, is now widely used for measuring superoxide-scavenging of other antioxidants. However, the strong pH effect has been ignored. In this study, the influencing factors have been systematically investigated for the first time, and a number of experiments have proved that the pH is of major importance. As major antioxidants contain carboxylic acid, ester, or lactone groups, pH 8.2 should be modified to physiological pH 7.4. The improved procedure is as follows. A pyrogallol solution (in 1 M HCl) is thoroughly mixed with pH 7.4 Tris-HCl buffer; A(325 nm) is measured every 30 s for 5 min at 37 °C. As the ΔA(325 nm, control) value reflects the initial concentration of substrate (•)O(2)(-), it should be well controlled to guarantee the accuracy of the method. The improved pyrogallol method is a reliable and cheap superoxide-scavenging assay suitable for all types of antioxidants.
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Affiliation(s)
- Xican Li
- School of Chinese Herbal Medicine, Guangzhou University of Chinese Medicine , Waihuang East Road No. 232, Guangzhou Higher Education Mega Center, 510006 Guangzhou, China.
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9
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Secilmis-Canbay H, Cubuk-Demiralay E, Alsancak G, Ozkan SA. The Combined Effect of the Organic Modifier Content and pH of the Mobile Phase on the Chromatographic Behavior of Some Arylpropionic and Arylacetic Acids to Optimize Their Liquid Chromatographic Determinations. Chromatographia 2012. [DOI: 10.1007/s10337-012-2255-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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10
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Gezici O, Kara H. Towards multimodal HPLC separations on humic acid-bonded aminopropyl silica: RPLC and HILIC behavior. Talanta 2011; 85:1472-82. [DOI: 10.1016/j.talanta.2011.06.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 06/07/2011] [Accepted: 06/11/2011] [Indexed: 11/27/2022]
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11
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Torres-Lapasió JR, Pous-Torres S, Baeza-Baeza JJ, García-Álvarez-Coque MC. Optimal experimental designs in RPLC at variable solvent content and pH based on prediction error surfaces. Anal Bioanal Chem 2011; 400:1217-30. [DOI: 10.1007/s00216-011-4709-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 01/20/2011] [Accepted: 01/22/2011] [Indexed: 12/01/2022]
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12
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Fields PR, Sun Y, Stalcup AM. Application of a modified linear solvation energy relationship (LSER) model to retention on a butylimidazolium-based column for high performance liquid chromatography. J Chromatogr A 2011; 1218:467-75. [PMID: 21168847 PMCID: PMC3023878 DOI: 10.1016/j.chroma.2010.11.058] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 11/19/2010] [Accepted: 11/24/2010] [Indexed: 10/18/2022]
Abstract
Previously, a new HPLC stationary phase based on n-butylimidazolium bromide was investigated using a linear solvation energy relationship (LSER) to systematically evaluate the intermolecular interactions between 32 test solutes and the stationary phase. The results and further comparisons with conventional reversed phase systems revealed that retention properties are similar to phenyl phases in both methanol/water and acetonitrile/water mixtures. In this work, the LSER model is extended by including the degree of ionization molecular descriptor, D, which takes into account the pK(a) of ionizable analytes and the pH of the mobile phase. The D molecular descriptor has been further divided into D(+) and D(-) components that separately account for the ionization of basic and acidic solutes, respectively. This is the first study where the ionization terms for weakly acidic solutes and weakly basic solutes have been separated. LSER results obtained with the expanded solute set with and without the inclusion of the D(+) and D(-) solute descriptors were compared. The improved correlation and standard error obtained for the expanded test set in the presence and absence of the D(+) and D(-) descriptors (R(2): 0.987 vs 0.846; SE: 0.051 vs 0.163 for 60% MeOH) support inclusion of these additional terms. Further, the coefficients obtained from the multiple linear regression for the expanded test set with the D(+) and D(-) descriptors were more consistent with the coefficients obtained when the test set included just neutral analytes. In addition, the expanded LSER model did a better job of predicting elution order for the ionizable analytes. This work provides further supporting evidence for the multimodal nature of the butylimidazolium stationary phase.
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Affiliation(s)
- P R Fields
- Department of Chemistry, P.O. Box 210172, University of Cincinnati, Cincinnati, OH 45221-0172, USA
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13
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Demiralay EC, Cubuk B, Ozkan SA, Alsancak G. Combined effect of polarity and pH on the chromatographic behavior of some angiotensin II receptor antagonists and optimization of their determination in pharmaceutical dosage forms. J Pharm Biomed Anal 2010; 53:475-82. [DOI: 10.1016/j.jpba.2010.05.020] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 05/19/2010] [Accepted: 05/21/2010] [Indexed: 11/27/2022]
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14
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Demiralay EC, Alsancak G, Ozkan SA. Determination of pK
a
values of nonsteroidal antiinflammatory drug-oxicams by RP-HPLC and their analysis in pharmaceutical dosage forms. J Sep Sci 2009; 32:2928-36. [DOI: 10.1002/jssc.200900234] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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15
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Wiczling P, Kaliszan R. Influence of pH on Retention in Linear Organic Modifier Gradient RP HPLC. Anal Chem 2008; 80:7855-61. [DOI: 10.1021/ac801093u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
| | - Roman Kaliszan
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gen. J. Hallera 107, 80-416 Gdańsk, Poland
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16
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Biesaga M, Ochnik U, Pyrzynska K. Analysis of phenolic acids in fruits by HPLC with monolithic columns. J Sep Sci 2008; 30:2929-34. [PMID: 17960844 DOI: 10.1002/jssc.200700247] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Reversed-phase HPLC was optimised for simultaneous determination of several derivatives of benzoic and hydroxycinnamic acids (so-called phenolic acids) in plums using a commercially available monolithic column. Mobile phase pH and concentration of organic modifier (methanol and acetonitrile) were tested in order to obtain the best resolution. Satisfactory separation was achieved in gradient mode with a mobile phase consisting of 50 mM phosphate buffer at pH 2.2 (solvent A) and acetonitrile (solvent B). The limits of detection for a UV detector ranged between 0.098 and 2.04 microg/mL for vanillic acid and p-hydroxyphenylacetic acid, respectively. The developed method was used for monitoring the content of polyphenolic acids in plums during their ripening process. The presence of these constituents was confirmed by checking their MS spectra.
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17
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Amiri AA, Hemmateenejad B, Safavi A, Sharghi H, Beni ARS, Shamsipur M. Structure-retention and mobile phase-retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile-water mixtures. Anal Chim Acta 2007; 605:11-9. [PMID: 18022405 DOI: 10.1016/j.aca.2007.10.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Revised: 10/08/2007] [Accepted: 10/09/2007] [Indexed: 11/18/2022]
Abstract
The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile-water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet-Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure-property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter (pi*) and hydrogen-bond basicity (beta), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (logP) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile-water binary solvents.
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Affiliation(s)
- A. C. Duarte
- a Departamento de Química , Universidade de Aveiro , Aveiro, Portugal
| | - S. Capelo
- b Departamento de Ecologia , Universidade de Évora , Évora, Portugal
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19
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Subirats X, Bosch E, Rosés M. Retention of ionisable compounds on high-performance liquid chromatography XVII. J Chromatogr A 2007; 1138:203-15. [PMID: 17118378 DOI: 10.1016/j.chroma.2006.10.087] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 10/24/2006] [Accepted: 10/30/2006] [Indexed: 11/22/2022]
Abstract
The use of methanol-aqueous buffer mobile phases in HPLC is a common election when performing chromatographic separations of ionisable analytes. The addition of methanol to the aqueous buffer to prepare such a mobile phase changes the buffer capacity and the pH of the solution. In the present work, the variation of these buffer properties is studied for acetic acid-acetate, phosphoric acid-dihydrogenphosphate-hydrogenphosphate, citric acid-dihydrogencitrate-hydrogencitrate-citrate, and ammonium-ammonia buffers. It is well established that the pH change of the buffers depends on the initial concentration and aqueous pH of the buffer, on the percentage of methanol added, and on the particular buffer used. The proposed equations allow the pH estimation of methanol-water buffered mobile phases up to 80% in volume of organic modifier from initial aqueous buffer pH and buffer concentration (before adding methanol) between 0.001 and 0.01 mol L(-1). From both the estimated pH values of the mobile phase and the estimated pKa of the ionisable analytes, it is possible to predict the degree of ionisation of the analytes and therefore, the interpretation of acid-base analytes behaviour in a particular methanol-water buffered mobile phase.
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Affiliation(s)
- Xavier Subirats
- Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, E-08028 Barcelona, Spain
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20
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García-Alvarez-Coque MC, Torres-Lapasió JR, Baeza-Baeza JJ. Models and objective functions for the optimisation of selectivity in reversed-phase liquid chromatography. Anal Chim Acta 2006; 579:125-45. [PMID: 17723737 DOI: 10.1016/j.aca.2006.07.028] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 07/11/2006] [Accepted: 07/13/2006] [Indexed: 11/24/2022]
Abstract
Interpretive methodologies are the most efficient tools for finding the optimal conditions in chromatography. These methodologies are supported by models or algorithms able to infer the system behaviour upon changes in the experimental factors. Once the models are built with data obtained from sets of carefully designed experiments, molecular modelling or other approaches, they can be applied to predict the performance of new conditions. The different elements involved in these methodologies, for both isocratic and gradient elution, are given. Special attention is devoted to the description of retention, owing to its major impact on the prediction of chromatographic resolution. Several models considering the main factors affecting retention (i.e. organic modifiers, pH and temperature), and procedures that enhance the predictions, are presented. Both the existence of skewed peaks and the effect of elution conditions on peak profiles are considered. Finally, the assessment of resolution, as well as other secondary aims that affect the practical suitability of the optimal conditions, is discussed.
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Affiliation(s)
- M C García-Alvarez-Coque
- Departament de Química Analítica, Universitat de València, c/Dr. Moliner 50, 46100 Burjassot, Spain.
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21
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Subirats X, Bosch E, Rosés M. Retention of ionisable compounds on high-performance liquid chromatography. J Chromatogr A 2006; 1121:170-7. [PMID: 16753172 DOI: 10.1016/j.chroma.2006.03.126] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2005] [Revised: 03/30/2006] [Accepted: 03/31/2006] [Indexed: 11/29/2022]
Abstract
In agreement with our previous studies and those of other authors, it is shown that much better fits of retention time as a function of pH are obtained for acid-base analytes when pH is measured in the mobile phase, than when pH is measured in the aqueous buffer when buffers of different nature are used. However, in some instances it may be more practical to measure the pH in the aqueous buffer before addition of the organic modifier. Thus, an open methodology is presented that allows prediction of chromatographic retention of acid-base analytes from the pH measured in the aqueous buffer. The model presented estimates the pH of the buffer and the pKa of the analyte in a particular acetonitrile/water mobile phase from the pH and pKa values in water. The retention of the analyte can be easily estimated, at a buffer pH close to the solute pKa, from these values and from the retentions of the pure acidic and basic forms of the analyte. Since in many instances, the analyte pKa values in water are not known, the methodology has been also tested by using Internet software, at reach of many chemists, which calculates analyte pKa values from chemical structure. The approach is successfully tested for some pharmaceutical drugs.
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Affiliation(s)
- Xavier Subirats
- Department of Analytical Chemistry, University of Barcelona, Martí i Franquès 1-11, E-08028 Barcelona, Spain
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