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Velozo CT, Cabral LM, Pinto EC, de Sousa VP. Lopinavir/Ritonavir: A Review of Analytical Methodologies for the Drug Substances, Pharmaceutical Formulations and Biological Matrices. Crit Rev Anal Chem 2021; 52:1846-1862. [PMID: 34024199 DOI: 10.1080/10408347.2021.1920364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Lopinavir/ritonavir is a potent coformulation of protease inhibitors used against HIV infection. Lopinavir is the main responsible for viral load suppression, whereas ritonavir is a pharmacokinetic enhancer. Both of them have recently gained relevance as candidate drugs against severe coronavirus disease (COVID-19). However, significant beneficial effects were not observed in randomized clinical trials. This review summarizes the main physical-chemical, pharmacodynamic, and pharmacokinetic properties of ritonavir and lopinavir, along with the analytical methodologies applied for biological matrices, pharmaceutical formulations, and stability studies. The work also aimed to provide a comprehensive impurity profile for the combined formulation. Several analytical methods in four different pharmacopeias and 37 articles in literature were evaluated and summarized. Chromatographic methods for these drugs frequently use C8 or C18 stationary phases with acetonitrile and phosphate buffer (with ultraviolet detection) or acetate buffer (with tandem mass spectrometry detection) as the mobile phase. Official compendia methods show disadvantages as extended total run time and complex mobile phases. HPLC tandem-mass spectrometry provided high sensitivity in methodologies applied for human plasma and serum samples, supporting the therapeutic drug monitoring in HIV patients. Ritonavir and lopinavir major degradation products arise in alkaline and acidic environments, respectively. Other non-chromatographic methods were also summarized. Establishing the impurity profile for the combined formulation is challenging due to a large number of impurities reported. Easier and faster analytical methods for impurity assessment are still needed.
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Affiliation(s)
- Carolina Trajano Velozo
- Department of Drugs and Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Lucio Mendes Cabral
- Department of Drugs and Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Eduardo Costa Pinto
- Department of Drugs and Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Valéria Pereira de Sousa
- Department of Drugs and Pharmaceutics, Faculty of Pharmacy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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2
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Žuvela P, Skoczylas M, Jay Liu J, Ba Czek T, Kaliszan R, Wong MW, Buszewski B, Héberger K. Column Characterization and Selection Systems in Reversed-Phase High-Performance Liquid Chromatography. Chem Rev 2019; 119:3674-3729. [PMID: 30604951 DOI: 10.1021/acs.chemrev.8b00246] [Citation(s) in RCA: 143] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Reversed-phase high-performance liquid chromatography (RP-HPLC) is the most popular chromatographic mode, accounting for more than 90% of all separations. HPLC itself owes its immense popularity to it being relatively simple and inexpensive, with the equipment being reliable and easy to operate. Due to extensive automation, it can be run virtually unattended with multiple samples at various separation conditions, even by relatively low-skilled personnel. Currently, there are >600 RP-HPLC columns available to end users for purchase, some of which exhibit very large differences in selectivity and production quality. Often, two similar RP-HPLC columns are not equally suitable for the requisite separation, and to date, there is no universal RP-HPLC column covering a variety of analytes. This forces analytical laboratories to keep a multitude of diverse columns. Therefore, column selection is a crucial segment of RP-HPLC method development, especially since sample complexity is constantly increasing. Rationally choosing an appropriate column is complicated. In addition to the differences in the primary intermolecular interactions with analytes of the dispersive (London) type, individual columns can also exhibit a unique character owing to specific polar, hydrogen bond, and electron pair donor-acceptor interactions. They can also vary depending on the type of packing, amount and type of residual silanols, "end-capping", bonding density of ligands, and pore size, among others. Consequently, the chromatographic performance of RP-HPLC systems is often considerably altered depending on the selected column. Although a wide spectrum of knowledge is available on this important subject, there is still a lack of a comprehensive review for an objective comparison and/or selection of chromatographic columns. We aim for this review to be a comprehensive, authoritative, critical, and easily readable monograph of the most relevant publications regarding column selection and characterization in RP-HPLC covering the past four decades. Future perspectives, which involve the integration of state-of-the-art molecular simulations (molecular dynamics or Monte Carlo) with minimal experiments, aimed at nearly "experiment-free" column selection methodology, are proposed.
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Affiliation(s)
- Petar Žuvela
- Department of Chemistry , National University of Singapore , Singapore 117543 , Singapore
| | - Magdalena Skoczylas
- Department of Environmental Chemistry and Bioanalytics, Center for Modern Interdisciplinary Technologies , Nicolaus Copernicus University , Wileńska 4 , 87-100 Toruń , Poland
| | - J Jay Liu
- Department of Chemical Engineering , Pukyong National University , 365 Sinseon-ro , Nam-gu, 48-513 Busan , Korea
| | | | | | - Ming Wah Wong
- Department of Chemistry , National University of Singapore , Singapore 117543 , Singapore
| | - Bogusław Buszewski
- Department of Environmental Chemistry and Bioanalytics, Center for Modern Interdisciplinary Technologies , Nicolaus Copernicus University , Wileńska 4 , 87-100 Toruń , Poland
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Nasuto R. The Influence of the Concentration of Cyclohexane Radicals Bonded with an Si100 Silica Gel Surface upon the Retention of Some Hydrocarbons in Gas Chromatography. ADSORPT SCI TECHNOL 2016. [DOI: 10.1260/0263617001493260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Four adsorbents based on silica gel Si100 with chemically bonded cyclohexane have been prepared as stationary phases for gas chromatography. The concentrations of cyclohexane radicals thus bonded with the silica gel surface were 1.35, 3.35, 4.17 and 6.02 μmol/m2, respectively. Separation of aliphatic (C6–C12), aromatic (benzene, toluene and m-xylene) and some polar organic compounds (chloroform, ethylene chloride, chlorobenzene, p-chlorotoluene and ethyl benzene) by gas chromatography using columns packed with the prepared adsorbents was studied. It was concluded that the retention of some compounds was increased on the column packed with an adsorbent of 1.35 μmol/m2 concentration relative to that measured on the column packed with the unmodified silica gel. On columns packed with adsorbents with a higher bonded phase concentration than 1.35 μmol/m2, the retention times of all the compounds studied chromatographically decreased with an increase in the bonded phase concentration.
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Affiliation(s)
- R. Nasuto
- Faculty of Chemistry, Maria Curie-Sklodowska University, Pl. M. Curie-Sklodowskiej 3, 20-031 Lublin, Poland
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Jambor E, Bona A, Schmidt J, Mark L, Ohmacht R. Preparation and investigation of LC packing made by microwave-assisted solid-phase synthesis. J Sep Sci 2013; 36:827-31. [DOI: 10.1002/jssc.201200610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 11/20/2012] [Accepted: 11/21/2012] [Indexed: 11/11/2022]
Affiliation(s)
| | - Agnes Bona
- Institute of Biochemistry and Medical Chemistry; Medical School; University of Pecs; Pecs; Hungary
| | | | | | - Robert Ohmacht
- Institute of Biochemistry and Medical Chemistry; Medical School; University of Pecs; Pecs; Hungary
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Rafferty JL, Siepmann JI, Schure MR. A molecular simulation study of the effects of stationary phase and solute chain length in reversed-phase liquid chromatography. J Chromatogr A 2012; 1223:24-34. [DOI: 10.1016/j.chroma.2011.11.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 11/17/2011] [Accepted: 11/20/2011] [Indexed: 10/15/2022]
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6
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Wisser FM, Abele M, Gasthauer M, Müller K, Moszner N, Kickelbick G. Detection of surface silanol groups on pristine and functionalized silica mixed oxides and zirconia. J Colloid Interface Sci 2012; 374:77-82. [PMID: 22342222 DOI: 10.1016/j.jcis.2012.01.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/16/2011] [Accepted: 01/08/2012] [Indexed: 11/16/2022]
Abstract
The surface hydroxyl content and surface structure of silica and other oxides with and without surface modification were systematically studied by solid state (29)Si NMR, thermogravimetric analysis, and the lithium alanate method. Aerosil 90 as a well described reference system and functionalized zirconia-silica particles were used in the validation of the lithium alanate method. 3-Methacryloxypropyltrimethoxysilane and dodecylphosphonic acid were applied as surface modifiers. The determination of silanol content of Aerosil 90 by (29)Si NMR and TGA confirms the results obtained by the lithium alanate method, which also allows for the determination of the remaining surface hydroxyl content after surface modification. For both silane coupling agents, the residual hydroxyl content of modified zirconia-silica is decreased by a factor of approximately 2 compared with that of the unmodified mixed oxide, whereas after modification with dodecylphosphonic acid, the hydroxyl content is slightly higher. These results are again in good agreement with those by (29)Si NMR confirming that the lithium alanate method is a reliable and easily practicable method for surface hydroxyl determination.
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Affiliation(s)
- Florian M Wisser
- Saarland University, Inorganic Solid State Chemistry, Am Markt Zeile 3, D-66125 Saarbrücken, Germany
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Zhang Y, Luo H, Carr PW. Silica-based, hyper-crosslinked acid stable stationary phases for high performance liquid chromatography. J Chromatogr A 2011; 1228:110-24. [PMID: 21906745 DOI: 10.1016/j.chroma.2011.07.096] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Revised: 07/26/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
A new family of hyper-crosslinked (HC) phases for use under very aggressive acid conditions including those encountered in ultra-fast, high temperature two-dimensional liquid chromatography (2DLC) has been recently introduced. This type of stationary phase shows significantly enhanced acid and thermal stability compared to the most acid stable, commercial RPLC phases. In addition, the use of "orthogonal" chemistry to make surface-confined polymer networks ensures good reproducibility and high efficiency. One of the most interesting features of the HC phases is the ability to derivatize the surface aromatic groups with various functional groups. This has led to the development of a family of hyper-crosslinked phases possessing a wide variety of chromatographic selectivities by attaching hydrophobic (e.g. -C₈), ionizable (e.g. -COOH, -SO₃H), aromatic (e.g. -toluene) or polar (e.g. -OH) species to the aromatic polymer network. HC reversed phases with various degrees of hydrophobicity and mixed-mode HC phases with added strong and weak cation exchange sites have been synthesized, characterized and applied. These silica-based acid-stable HC phases, with their attractive chromatographic properties, should be very useful in the separation of bases or biological analytes in acidic media, especially at elevated temperatures. This work reviews prior research on HC phases and introduces a novel HC phase made by alternative chemistry.
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Affiliation(s)
- Yu Zhang
- Department of Chemistry, University of Minnesota, 207 Pleasant St. S.E., Minneapolis, MN 55455, USA
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Kwietniewski L. THE EFFECT OF THE CHAIN LENGTH OF BONDED PHASE ON RETENTION OF AROMATIC SOLUTES IN RP LC WITH PURE WATER AS MOBILE PHASE. J LIQ CHROMATOGR R T 2010. [DOI: 10.1080/10826076.2010.503744] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- L. Kwietniewski
- a Faculty of Mathematics and Natural Science, Institute of Biotechnology, Chair of Bioanomaterials, John Paul II Catholic University of Lublin , Lublin, Poland
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9
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Luo H, Ma L, Zhang Y, Carr PW. Synthesis and characterization of silica-based hyper-crosslinked sulfonate-modified reversed stationary phases. J Chromatogr A 2008; 1182:41-55. [PMID: 18207150 PMCID: PMC3217304 DOI: 10.1016/j.chroma.2007.11.104] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Revised: 11/21/2007] [Accepted: 11/30/2007] [Indexed: 11/26/2022]
Abstract
A novel type of silica-based sulfonate-modified reversed phase ((-)SO3-HC-C8) has been synthesized; it is based on a newly developed acid stable "hyper-crosslinked" C8 derivatized reversed phase, denoted HC-C8. The (-)SO3-HC-C8 phases containing controlled amounts of sulfonyl groups were made by sulfonating the aromatic hyper-crosslinked network of the HC-C(8) phase at different temperatures. The (-)SO3-HC-C8 phases are only slightly less hydrophobic than the parent HC-C8 phase. The added sulfonyl groups provide a unique strong cation-exchange selectivity to the hydrophobic hyper-crosslinked substrate as indicated by the very large C coefficient as shown through Snyder's hydrophobic subtraction reversed-phase characterization method. This cation-exchange activity clearly distinguishes the sulfonated phase from all other reversed phases as confirmed by the very high values of Snyder's column comparison function F(s). In addition, as was found in previous studies of silica-based and zirconia-based reversed phases, a strong correlation between the cation-exchange interaction and hydrophobic interaction was observed for these sulfonated phases in studies of the retention of cationic solutes. The overall chromatographic selectivity of these (-)SO3-HC-C8 phases is greatly enhanced by its high hydrophobicity through a "hydrophobically assisted" ion-exchange retention process.
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Affiliation(s)
| | | | - Yu Zhang
- Department of Chemistry, University of Minnesota, Smith and Kolthoff Hall, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
| | - Peter W. Carr
- Department of Chemistry, University of Minnesota, Smith and Kolthoff Hall, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
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10
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Vailaya A. Fundamentals of Reversed Phase Chromatography: Thermodynamic and Exothermodynamic Treatment. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-200052969] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Anant Vailaya
- a Merck Research Laboratories , Rahway, New Jersey, USA
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11
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Chen N, Zhang Y, Lu P. Standardization of Different Octadecyl Bonded Phases Based on the Retention Equation in Reversed-Phase High-Performance Liquid Chromatography. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/10826079208016375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- N. Chen
- a National Chromatographic R. & A. Center , Dalian Institute of Chemical Physics Chinese Academy of Sciences , 116012 , Dalian , People's Republic of China
| | - Y. Zhang
- a National Chromatographic R. & A. Center , Dalian Institute of Chemical Physics Chinese Academy of Sciences , 116012 , Dalian , People's Republic of China
| | - P. Lu
- a National Chromatographic R. & A. Center , Dalian Institute of Chemical Physics Chinese Academy of Sciences , 116012 , Dalian , People's Republic of China
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12
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Biernat JF, Konieczka P, Tarbet BJ, Bradshaw JS, Izatt RM. Complexing and Chelating Agents Immobilized on Silica Gel and Related Materials and Their Application for Sorption of Inorganic Species. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/03602549408006624] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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Engelhardt H, Blay C, Saar J. Reversed Phase Chromatography – the Mystery of Surface Silanols. Chromatographia 2005. [DOI: 10.1365/s10337-005-0573-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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14
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Trammell BC, Boissel CA, Carignan C, O'Shea DJ, Hudalla CJ, Neue UD, Iraneta PC. Development of an accelerated low-pH reversed-phase liquid chromatography column stability test. J Chromatogr A 2004; 1060:153-63. [PMID: 15628158 DOI: 10.1016/j.chroma.2004.04.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The important experimental design criteria for an accelerated low-pH RPLC column stability test are discussed. The influence of method variables on the amount and rate of retention-loss and the final optimized parameters for the accelerated low-pH RPLC stability test are presented. The retention-loss curves for selected C8 and C18 stationary phases are compared. These studies indicate that ligand chain length, functionality and bonding density play an important role in determining the low-pH stability of a stationary phase. Additionally, elemental analysis data are used to infer the mechanism responsible for the observed retention-loss under low-pH conditions.
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15
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Nawrocki J, Dunlap C, McCormick A, Carr PW. Part I. Chromatography using ultra-stable metal oxide-based stationary phases for HPLC. J Chromatogr A 2004; 1028:1-30. [PMID: 14969280 DOI: 10.1016/j.chroma.2003.11.052] [Citation(s) in RCA: 228] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The first part of the review contrasts the main drawbacks of silica-based packings such as their relative thermal and chemical instability with excellent stability of metal oxides. The paper concerns mainly ZrO2, TiO2 and Al2O3. Methods of preparation of spherical particles for HPLC are described. Surface chemistry of the oxides is, however, very different from that of silica. Ability of the oxides to ion- and ligand exchange is discussed from a chromatographic point of view.
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Affiliation(s)
- J Nawrocki
- Department of Water Treatment Technology, Faculty of Chemistry, A. Mickiewicz University, Drzymały 24, 60-613 Poznañ, Poland.
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16
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Abstract
The linear relation ln k' = Bn + ln A between the retention factor k' in liquid adsorption chromatography (LAC) and the number of repeat units n within a homologous series of oligomers is called Martin's rule. This empirical relation was supported by the retention behavior of the homologous series of different classes of oligomers but had no theoretical justification. In this paper, it is demonstrated that Martin's rule is a consequence of the general theory of liquid chromatography and the molecular sense of coefficients B and A is clarified: B is the Gibbs energy of the repeat unit of the long polymer chain adsorbed at the wall surface, and A is a combination different parameters which characterize the column and the adsorption correlation length H. The theory predicts the deviations from the linear dependence under conditions of weak adsorption between repeat units and stationary phase when H is close to radius of gyration Rg. Experimental data for retention volumes and selectivity of poly(ethylene glycol)s are given for normal and reversed-phase LAC on different columns in acetone-water and methanol-water as mobile phases. These data show excellent agreement between the theory and experiments. It is shown that Martin's rule holds under special conditions, which are theoretically defined by the relation H > Rg/1.5.
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Affiliation(s)
- Alexander Skvortsov
- Chemical-Pharmaceutical Academy, Prof. Popova 14, 197376 St. Petersburg, Russia
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17
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Szepesy L. Evaluation of column characteristics in RPLC using linear solvation energy relationships (LSERs). J Sep Sci 2003. [DOI: 10.1002/jssc.200390027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Buchmeiser MR. New synthetic ways for the preparation of high-performance liquid chromatography supports. J Chromatogr A 2001; 918:233-66. [PMID: 11407572 DOI: 10.1016/s0021-9673(00)00129-1] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The latest developments and in particular important synthetic aspects for the preparation of modern HPLC supports are reviewed. In this context, the chemistry of inorganic supports based on silica, zirconia, titania or aluminum oxide as well as of organic supports based on poly(styrene-divinylbenzene), acrylates, methacrylates and other, more specialized polymers is covered. Special consideration is given to modern approaches such as sol-gel technology, molecular imprinting, perfusion chromatography, the preparation of monolithic separation media as well as to organic HPLC supports prepared by new polymer technologies such as ring-opening metathesis polymerization. Synthetic particularities relevant for the corresponding applications are outlined.
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Affiliation(s)
- M R Buchmeiser
- Institute of Analytical Chemistry and Radiochemistry, University of Innsbruck, Austria.
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21
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Sándi Á, Szepesy L. Evaluation and modulation of selectivity in reversed-phase high-performance liquid chromatography. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00361-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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22
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Buszewski B, Gadzała-Kopciuch R, Kaliszan R, Markuszewski M, Matyska MT, Pesek JJ. Polyfunctional chemically bonded stationary phase for reversed phase high-performance liquid chromatography. Chromatographia 1998. [DOI: 10.1007/bf02467590] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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23
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Engelhardt H, Nikolov M, Arangio M, Scherer M. Studies on shape selectivity of RP C18-columns. Chromatographia 1998. [DOI: 10.1007/bf02467669] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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24
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25
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26
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Park JH, Lee YK, Weon YC, Tan LC, Li J, Li L, Evans JF, Carr PW. Revisionist look at solvophobic driving forces in reversed-phase liquid chromatography IV. Partitioning vs. adsorption mechanism on various types of polymeric bonded phases. J Chromatogr A 1997. [DOI: 10.1016/s0021-9673(97)00014-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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27
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HPLC in industry—A well established procedure for characterizing RP-stationary phases. Chromatographia 1997. [DOI: 10.1007/bf02505565] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Tan LC, Carr PW, Abraham MH. Study of retention in reversed-phase liquid chromatography using linear solvation energy relationships I. The stationary phase. J Chromatogr A 1996. [DOI: 10.1016/s0021-9673(96)00459-1] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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29
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Ihara T, Sugimoto Y, Asada M, Nakagama T, Hobo T. Influence of the method of preparation of chiral stationary phases on enantiomer separations in high-performance liquid chromatography. J Chromatogr A 1995. [DOI: 10.1016/0021-9673(94)00753-v] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Dzido TH, Engelhardt H. Retention parameters of aromatic hydrocarbons with mono-substituted polar groups in binary RP-HPLC systems. Chromatographia 1994. [DOI: 10.1007/bf02320458] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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31
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Tijssen R, Schoenmakers PJ, Böhmer MR, Koopal LK, Billiet HA. Lattice models for the description of partitioning/ adsorption and retention in reversed-phase liquid chromatography, including surface and shape effects. J Chromatogr A 1993. [DOI: 10.1016/0021-9673(93)80801-e] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Möckel HJ, Dreyer U. Second order retention effects in reversed-phase liquid chromatography. 1. Influence of solute size. Chromatographia 1993. [DOI: 10.1007/bf02275858] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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33
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Fóti G, Belvito ML, Alvarez-Zepeda A, Kováts ES. Retention on non-polar adsorbents in liquid—solid chromatography. J Chromatogr A 1993. [DOI: 10.1016/0021-9673(93)80438-e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Kallury K, Cheung M, Ghaemmaghami V, Krull U, Thompson M. Silanization of oxidized silicon and aluminum surfaces with functionalized silanes with characterization by wettability, ellipsometry, XPS and quartz crystal microbalance studies. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/0166-6622(92)80062-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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36
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Niemann C, Saenger W, Nuck R, Pfannemüller B. H.p.l.c. of 4-nitrophenyl-α-d-malto-oligosaccharides. Carbohydr Res 1991. [DOI: 10.1016/0008-6215(91)84003-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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37
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Cheong WJ, Carr PW. Study of partition models in reversed-phase liquid chromatography based on measured mobile phase solute activity coefficients. J Chromatogr A 1990. [DOI: 10.1016/s0021-9673(00)96986-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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38
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Bush S, Jorgenson J. Confirmation and application of transmission near infrared absorption technique for absolute quantitation of functional groups on silica gel. J Chromatogr A 1990. [DOI: 10.1016/s0021-9673(01)81492-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Application of diode array detectors for solute identification in toxicological analysis. Chromatographia 1989. [DOI: 10.1007/bf02261012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Engelhardt H, Löw H, Eberhardt W, Mauß M. Polymer encapsulated staionary phases: Advantages, properties and selectivities. Chromatographia 1989. [DOI: 10.1007/bf02258974] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Synthesis and characterization of novel bonded phases for reversed-phase liquid chromatography. Chromatographia 1989. [DOI: 10.1007/bf02319555] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Sentell KB, Dorsey JG. Retention mechanisms in reversed-phase chromatography. Stationary phase bonding density and solute selectivity. J Chromatogr A 1989; 461:193-207. [PMID: 2708472 DOI: 10.1016/s0021-9673(00)94287-0] [Citation(s) in RCA: 103] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Chromatographic selectivity for small, non-polar solutes has been determined as a function of monomeric octadecyl stationary phase bonding density over the range 1.74-4.07 mumol/m2. Phenyl or shape selectivity increases with increasing bonding density, whereas methylene selectivity remains approximately constant. These findings are in agreement with the mean field statistical thermodynamic theory of Dill, which predicts that increased stationary phase chain density should lead to increased anisotropic chain ordering and increased solute-shape selectivity. These studies provide further evidence that partitioning, not adsorption, is the dominant mode of retention for small, non-polar molecules in reversed-phase liquid chromatography.
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Affiliation(s)
- K B Sentell
- Department of Chemistry, University of Florida, Gainesville 32611
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Czok M, Engelhardt H. A practical description of retention in reversed phase chromatography using four parameters. Chromatographia 1989. [DOI: 10.1007/bf02290396] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ratanathanawongs S, Giddings J. High-speed size characterization of chromatographic silica by flow/hyperlayer field-flow fractionation. J Chromatogr A 1989. [DOI: 10.1016/s0021-9673(01)93988-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Influence of the porous silica gel structure on the coverage density of a chemically bonded C18 phase for high-performance liquid chromatography. J Chromatogr A 1988. [DOI: 10.1016/s0021-9673(00)94433-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Buszewski B, suprynowicz Z. High-density chemically bonded octadecyl phases on silica gels and their application in high-performance liquid chromatography. Anal Chim Acta 1988. [DOI: 10.1016/s0003-2670(00)80754-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Koppenhoefer B, Allmendinger H, Peters B. Modifizierung von Kieselgel mit Weinsäurederivaten hoher Stereoisomerenreinheit und Charakterisierung durch Festkörper-13C-NMR-CP-MAS-Spektroskopie. ACTA ACUST UNITED AC 1987. [DOI: 10.1002/jlac.198719870860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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