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Collados CC, Huber C, Söllner J, Grass JP, Inayat A, Durdyyev R, Smith AS, Wisser D, Hartmann M, Thommes M. Assessment of Hydrophilicity/Hydrophobicity in Mesoporous Silica by Combining Adsorption, Liquid Intrusion, and Solid-State NMR Spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:12853-12867. [PMID: 38861921 DOI: 10.1021/acs.langmuir.3c03516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
We have developed a comprehensive strategy for quantitatively assessing the hydrophilicity/hydrophobicity of nanoporous materials by combining advanced adsorption studies, novel liquid intrusion techniques, and solid-state NMR spectroscopy. For this, we have chosen a well-defined system of model materials, i.e., the highly ordered mesoporous silica molecular sieve SBA-15 in its pristine state and functionalized with different amounts of trimethylsilyl (TMS) groups, allowing one to accurately tailor the surface chemistry while maintaining the well-defined pore structure. For an absolute quantification of the trimethylsilyl group density, quantitative 1H solid-state NMR spectroscopy under magic angle spinning was employed. A full textural characterization of the materials was obtained by high-resolution argon 87 K adsorption, coupled with the application of dedicated methods based on nonlocal-density functional theory (NLDFT). Based on the known texture of the model materials, we developed a novel methodology allowing one to determine the effective contact angle of water adsorbed on the pore surfaces from complete wetting to nonwetting, constituting a powerful parameter for the characterization of the surface chemistry inside porous materials. The surface chemistry was found to vary from hydrophilic to hydrophobic as the TMS functionalization content was increased. For wetting and partially wetting surfaces, pore condensation of water is observed at pressures P smaller than the bulk saturation pressure p0 (i.e., at p/p0 < 1) and the effective contact angle of water on the pore walls could be derived from the water sorption isotherms. However, for nonwetting surfaces, pore condensation occurs at pressures above the saturation pressure (i.e., at p/p0 > 1). In this case, we investigated the pore filling of water (i.e., the vapor-liquid phase transition) by the application of a novel, liquid water intrusion/extrusion methodology, allowing one to derive the effective contact angle of water on the pore walls even in the case of nonwetting. Complementary molecular simulations provide density profiles of water on pristine and TMS-grafted silica surfaces (mimicking the tailored, functionalized experimental silica surfaces), which allow for a molecular view on the water adsorbate structure. Summarizing, we present a comprehensive and reliable methodology for quantitatively assessing the hydrophilicity/hydrophobicity of siliceous nanoporous materials, which has the potential to optimize applications in heterogeneous catalysis and separation (e.g., chromatography).
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Affiliation(s)
- Carlos Cuadrado Collados
- Institution of Separation Science and Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Christoph Huber
- Erlangen Center for Interface Research and Catalysis (ECRC), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Jakob Söllner
- Institution of Separation Science and Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Jan-Paul Grass
- Institute of Chemical Reaction Engineering (CRT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Alexandra Inayat
- Institute of Chemical Reaction Engineering (CRT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Rustam Durdyyev
- PULS Group, Institute for Theoretical Physics, Centre for Computational Advanced Materials and Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg, IZNF, Cauerstraße 4, Erlangen 91058, Germany
| | - Ana-Suncana Smith
- PULS Group, Institute for Theoretical Physics, Centre for Computational Advanced Materials and Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg, IZNF, Cauerstraße 4, Erlangen 91058, Germany
| | - Dorothea Wisser
- Erlangen Center for Interface Research and Catalysis (ECRC), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Martin Hartmann
- Erlangen Center for Interface Research and Catalysis (ECRC), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
| | - Matthias Thommes
- Institution of Separation Science and Technology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstr. 3, Erlangen 91058, Germany
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2
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Zhang Y, Zhao M, Fu C, Zhou S, Han H, Zhang M. Design and evaluation of semicarbazide-embeddedd stationary phases for liquid chromatography. J Chromatogr A 2024; 1720:464782. [PMID: 38442498 DOI: 10.1016/j.chroma.2024.464782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 02/19/2024] [Accepted: 02/29/2024] [Indexed: 03/07/2024]
Abstract
Semicarbazide, as a derivative of urea, constitutes a great variety of functional molecules for different needs. Herein, novel stationary phases with an incorporated semicarbazide group were proposed. Using aliphatic (docosanoyl, C22) and aromatic (benzoyl, Bz) hydrazides, the semicarbazide-embedded ligands were synthesized before chemical modification of the silica gel, allowing for an accurate interpretation of the chromatographic properties of the corresponding packings. The new stationary phases were water-wettable, due to the presence of highly polar groups. In particular, Bz-semicarbazide (Bz-SCD) stationary phase was sufficiently hydrophilic to run in hydrophilic interaction (HILIC) mode, whilst the C22 (C22-SCD) equivalent, in spite of its reversed-phase nature, was markedly less hydrophobic than the referenced polar-embedded ones. The versatility of C22-SCD was demonstrated with a large selection of analytes, including geometric isomers and standard mixtures of polycyclic aromatic hydrocarbons, sulfonamides, sulfonylurea, substituted ureas, pyridines and carbamates, fat-soluble colorants, antifungal metabolites, angiotensin II receptor blockers and calcium channel blockers.
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Affiliation(s)
- Yujie Zhang
- School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an 223000, China.
| | - Mingyang Zhao
- Jiangsu Hanbon Science & Technology Co., Ltd., Huai'an 223000, China
| | - Chuanbo Fu
- Jiangsu Hanbon Science & Technology Co., Ltd., Huai'an 223000, China
| | - Shouyong Zhou
- School of Chemistry and Chemical Engineering, Huaiyin Normal University, Huai'an 223000, China
| | - Haifeng Han
- Jiangsu Hanbon Science & Technology Co., Ltd., Huai'an 223000, China
| | - Mingliang Zhang
- Jiangsu Hanbon Science & Technology Co., Ltd., Huai'an 223000, China.
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3
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Ali AAKF, Danielson ND. Liquid chromatography of short chain carboxylic acids using a glutamic acid surfactant coated C18 stationary phase. Talanta 2020; 213:120807. [PMID: 32200935 DOI: 10.1016/j.talanta.2020.120807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 11/19/2022]
Abstract
A C18 column was modified with the anionic amino acid surfactant lauroyl-l-glutamate (LLG) to facilitate the separation of ten short-chain aliphatic carboxylic acids (oxalic, tartaric, malic, malonic, lactic, acetic, maleic, citric, fumaric, and succinic). The developed method was proven to be fast, versatile, and environmentally friendly. After the coating of the column using 1% LLG solution and optimizing chromatographic conditions such as pH and temperature, near baseline resolution of the ten carboxylic acids within 4 min with excellent peak shape at pH = 1.8 using 100% H2O acidified with sulfuric acid was possible. Although the design of this stationary phase, with the hydrophilic group at the end of the alkyl chain, seems to be in contrast to such columns designed for a totally aqueous mobile phase that have a polar (often amide) group embedded near the silica surface, no evidence of phase collapse was noted. Linear relationships of ln retention factor (k) versus 1/Temperature (T) (van't Hoff plots) were generated for all the acids indicating a single retention mechanism was likely. As the pH of the mobile phase decreased, the analyte retention factors increased due to the increase of the fraction of the analyte with neutral charge (alpha zero). The surfactant amide linkage, being electron donating, increased the pKa of the more acidic carboxyl group of glutamic acid so both carboxyl groups were protonated (neutral) at pH 1.8. The exact nature of the retention mechanism is uncertain but there certainly seems to be a pronounced hydrophobic component due to the large difference in retention of fumaric acid and methyl fumarate at pH 1.8. In addition, eleven beverage samples were analyzed for their aliphatic carboxylic acid contents. The results showed that malic, fumaric, and citric acids were the most common carboxylic acids in natural beverages with concentrations as high as 6432 ppm of malic acid in organic apple juice, 64 ppm of fumaric acid in organic concord juice, and 6543 ppm citric acid in strawberry lemonade juice.
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Affiliation(s)
| | - Neil D Danielson
- Department of Chemistry, 651 E. High Street, Miami University, Oxford, OH, 45056, USA.
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Zhao WJ, Chen XY, Liu YQ, Li P, Li HJ. Liquid chromatographic separation of alkaloids in herbal medicines: Current status and perspectives. J Sep Sci 2020; 43:1755-1772. [PMID: 32160388 DOI: 10.1002/jssc.202000081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/07/2020] [Accepted: 03/08/2020] [Indexed: 12/27/2022]
Abstract
Alkaloids are a widespread group of basic compounds in herbal medicines and have attracted great interest due to various pharmaceutical activities and desirable druggability. Their distinctive structures make chromatographic separation fairly difficult. Peak tailing, poor resolution, and inferior column-to-column reproducibility are common obstacles to overcome. In order to provide a valuable reference, the methodologies and/or strategies on liquid chromatographic separation of alkaloids in herbal medicines proposed from 2012 to 2019 are thoroughly summarized.
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Affiliation(s)
- Wen-Jing Zhao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, P.R. China
| | - Xu-Yan Chen
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, P.R. China
| | - Yu-Qian Liu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, P.R. China
| | - Ping Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, P.R. China
| | - Hui-Jun Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, P.R. China
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5
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Thermal pretreatments of superficially porous silica particles for high-performance liquid chromatography: Surface control, structural characterization and chromatographic evaluation. J Chromatogr A 2015; 1419:45-57. [DOI: 10.1016/j.chroma.2015.09.072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/18/2015] [Accepted: 09/22/2015] [Indexed: 11/17/2022]
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6
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Synthesis of the Coumarin-Containing Porous Silica as Column Packing Material. J Inorg Organomet Polym Mater 2015. [DOI: 10.1007/s10904-015-0293-3] [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]
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7
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Aral T, Aral H, Ziyadanoğulları B, Ziyadanoğulları R. Synthesis of a mixed-model stationary phase derived from glutamine for HPLC separation of structurally different biologically active compounds: HILIC and reversed-phase applications. Talanta 2014; 131:64-73. [PMID: 25281074 DOI: 10.1016/j.talanta.2014.07.060] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 07/18/2014] [Accepted: 07/21/2014] [Indexed: 10/25/2022]
Abstract
A novel mixed-mode stationary phase was synthesised starting from N-Boc-glutamine, aniline and spherical silica gel (4 µm, 60 Å). The prepared stationary phase was characterized by IR and elemental analysis. The new stationary phase bears an embedded amide group into phenyl ring, highly polar a terminal amide group and non-polar groups (phenyl and alkyl groups). At first, this new mixed-mode stationary phase was used for HILIC separation of four nucleotides and five nucleosides. The effects of different separation conditions, such as pH value, mobile phase and temperature, on the separation process were investigated. The optimum separation for nucleotides was achieved using HILIC isocratic elution with aqueous mobile phase and acetonitrile with 20°C column temperature. Under these conditions, the four nucleotides could be separated and detected at 265 nm within 14 min. Five nucleosides were separated under HILIC isocratic elution with aqueous mobile phase containing pH=3.25 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 265 nm within 14 min. Chromatographic parameters as retention factor, selectivity, theoretical plate number and peak asymmetry factor were calculated for the effect of temperature and water content in mobile phase on the separation process. The new column was also tested for nucleotides and nucleosides mixture and six analytes were separated in 10min. The chromatographic behaviours of these polar analytes on the new mixed-model stationary phase were compared with those of HILIC columns under similar conditions. Further, phytohormones and phenolic compounds were separated in order to see influence of the new stationary phase in reverse phase conditions. Eleven plant phytohormones were separated within 13 min using RP-HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and detected at 230 or 278 nm. The best separation conditions for seven phenolic compounds was also achieved using reversed-phase HPLC gradient elution with aqueous mobile phase containing pH=2.5 phosphate buffer (10mM) and acetonitrile with 20°C column temperature and seven phenolic compounds could be separated and detected at 230 nm within 16 min.
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Affiliation(s)
- Tarık Aral
- University of Batman, Faculty of Science and Art, Department of Chemistry, Batman, Turkey.
| | - Hayriye Aral
- University of Batman, Faculty of Science and Art, Department of Chemistry, Batman, Turkey.
| | | | - Recep Ziyadanoğulları
- University of Dicle, Faculty of Science, Department of Chemistry, Diyarbakır, Turkey
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8
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Giaginis C, Theocharis S, Tsantili-Kakoulidou A. Octanol/water partitioning simulation by RP-HPLC for structurally diverse acidic drugs: Comparison of three columns in the presence and absence of n
-octanol as the mobile phase additive. J Sep Sci 2013; 36:3830-6. [DOI: 10.1002/jssc.201300711] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 09/10/2013] [Accepted: 10/01/2013] [Indexed: 12/25/2022]
Affiliation(s)
- Costas Giaginis
- Department of Pharmaceutical Chemistry; School of Pharmacy; University of Athens, Panepistimiopolis; Zografou Athens Greece
- Department of Food Science and Nutrition; University of the Aegean; Myrina Lemnos Greece
| | - Stamatios Theocharis
- First Department of Pathology; Medical School, University of Athens; Goudi Athens Greece
| | - Anna Tsantili-Kakoulidou
- Department of Pharmaceutical Chemistry; School of Pharmacy; University of Athens, Panepistimiopolis; Zografou Athens Greece
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9
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Aral H, Aral T, Ziyadanoğulları B, Ziyadanoğulları R. Development of a novel amide-silica stationary phase for the reversed-phase HPLC separation of different classes of phytohormones. Talanta 2013; 116:155-63. [DOI: 10.1016/j.talanta.2013.05.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 05/01/2013] [Accepted: 05/04/2013] [Indexed: 10/26/2022]
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10
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Extension of the carotenoid test to superficially porous C18 bonded phases, aromatic ligand types and new classical C18 bonded phases. J Chromatogr A 2012; 1266:34-42. [DOI: 10.1016/j.chroma.2012.09.068] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/06/2012] [Accepted: 09/10/2012] [Indexed: 11/18/2022]
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11
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Rosa PCP, Jardim ICSF. Simultaneous determination of clobutinol hydrochloride and doxylamine succinate from syrups by RP HPLC using a new stationary phase containing embedded urea polar groups. BRAZ J PHARM SCI 2012. [DOI: 10.1590/s1984-82502012000200015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A new, simple, fast, reproducible and sensitive reversed phase HPLC method, using a new stationary phase containing embedded urea polar groups, has been developed and validated for the simultaneous determination of clobutinol hydrochloride (CLO) and doxylamine succinate (DOX) in syrups. The determination was carried out on a C8 urea column (125 mm x 3.9 mm i.d., 5 µm particle size) synthetized at the Liquid Chomatography Laboratory (LabCrom) of the Chemistry Institute of Unicamp. The mobile phase consisted of a mixture of acetonitrile:methanol:phosphate buffer (pH 2.5) in the gradient mode. The diode array detector (DAD) was operated at 230 nm for CLO and 262 nm for DOX. The method showed adequate precision, with relative standard deviations (RSD) less than 1%. The presence of the excipients did not interfere in the results of the analysis. Accuracy was determined by adding standards of the drugs to a placebo and good recovery values were obtained. The analytical curves were linear (r² 0.9999 for CLO and 0.9998 for DOX) over a wide concentration range (2.4-336 µg mL-1 for CLO and 2.3-63 µg mL-1 for DOX). The solutions were stable for at least 72 hours at room temperature. The criteria for validation using the ICH guidelines were fulfilled.
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12
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Mant CT, Hodges RS. Design of peptide standards with the same composition and minimal sequence variation to monitor performance/selectivity of reversed-phase matrices. J Chromatogr A 2012; 1230:30-40. [PMID: 22326185 PMCID: PMC3294100 DOI: 10.1016/j.chroma.2012.01.053] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 01/13/2012] [Accepted: 01/19/2012] [Indexed: 10/14/2022]
Abstract
The present manuscript extends our de novo peptide design approach to the synthesis and evaluation of a new generation of reversed-phase HPLC peptide standards with the same composition and minimal sequence variation (SCMSV). Thus, we have designed and synthesized four series of peptide standards with the sequences Gly-X-Leu-Gly-Leu-Ala-Leu-Gly-Gly-Leu-Lys-Lys-amide, where the N-terminal is either N(α)-acetylated (Series 1) or contains a free α-amino group (Series 3); and Gly-Gly-Leu-Gly-Gly-Ala-Leu-Gly-X-Leu-Lys-Lys-amide, where the N-terminal is either N(α)-acetylated (Series 2) or contains a free α-amino group (Series 4). In this initial study, the single substitution position, X, was substituted with alkyl side-chains (Ala
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Affiliation(s)
- Colin T. Mant
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, School of Medicine, Aurora, CO 80045, USA
| | - Robert S. Hodges
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, School of Medicine, Aurora, CO 80045, USA
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13
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Mant CT, Cepeniene D, Hodges RS. Reversed-phase HPLC of peptides: Assessing column and solvent selectivity on standard, polar-embedded and polar endcapped columns. J Sep Sci 2010; 33:3005-21. [DOI: 10.1002/jssc.201000518] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Giaginis C, Tsantili-Kakoulidou A. The performance of 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid as mobile phase additive in HPLC-based lipophilicity assessment. Biomed Chromatogr 2010; 25:606-12. [DOI: 10.1002/bmc.1491] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 06/28/2010] [Indexed: 11/09/2022]
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15
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Tsopelas F, Ochsenkühn-Petropoulou M, Tsantili-Kakoulidou A. Void volume markers in reversed-phase and biomimetic liquid chromatography. J Chromatogr A 2010; 1217:2847-54. [DOI: 10.1016/j.chroma.2010.02.062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 02/12/2010] [Accepted: 02/24/2010] [Indexed: 11/29/2022]
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17
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Characterization of Ascentis RP-Amide column: Lipophilicity measurement and linear solvation energy relationships. J Chromatogr A 2010; 1217:65-74. [DOI: 10.1016/j.chroma.2009.11.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 10/30/2009] [Accepted: 11/02/2009] [Indexed: 11/19/2022]
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18
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McCalley DV. The challenges of the analysis of basic compounds by high performance liquid chromatography: some possible approaches for improved separations. J Chromatogr A 2009; 1217:858-80. [PMID: 20031138 DOI: 10.1016/j.chroma.2009.11.068] [Citation(s) in RCA: 182] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Revised: 10/13/2009] [Accepted: 11/23/2009] [Indexed: 11/18/2022]
Abstract
This review considers some of the difficulties encountered with the analysis of ionised bases using reversed-phase chromatography, such as detrimental interaction with column silanol groups, and overloading which both lead to poor peak shapes. Methods of overcoming these problems in reversed-phase (RP) separations, by judicious selection of the column and mobile phase conditions, are discussed. Hydrophilic interaction chromatography is considered as an alternative method for the separation of some basic compounds.
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Affiliation(s)
- David V McCalley
- Centre for Research in Biomedicine, University of the West of England, Frenchay, Bristol BS16 1QY, UK.
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19
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Yao L, Feng Y, Da S. Preparation and Chromatographic Characterization of Zirconia Modified with Dodecylamine‐N,N‐dimethylenephosphonic Acid. J LIQ CHROMATOGR R T 2009. [DOI: 10.1081/jlc-200030530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Li‐Feng Yao
- a Department of Chemistry , Wuhan University , Wuhan , 430072 , P.R. China
- b Department of Chemistry , Wuhan University of Technology , Wuhan , P.R. China
| | - Yu‐Qi Feng
- a Department of Chemistry , Wuhan University , Wuhan , 430072 , P.R. China
| | - Shi‐Lu Da
- a Department of Chemistry , Wuhan University , Wuhan , 430072 , P.R. China
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20
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Poly(1-allylimidazole)-grafted silica, a new specific stationary phase for reversed-phase and anion-exchange liquid chromatography. J Chromatogr A 2009; 1216:3904-9. [DOI: 10.1016/j.chroma.2009.02.089] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 02/18/2009] [Accepted: 02/27/2009] [Indexed: 11/23/2022]
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21
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The effects of chain length, embedded polar groups, pressure, and pore shape on structure and retention in reversed-phase liquid chromatography: Molecular-level insights from Monte Carlo simulations. J Chromatogr A 2009; 1216:2320-31. [DOI: 10.1016/j.chroma.2008.12.088] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 12/22/2008] [Accepted: 12/29/2008] [Indexed: 11/22/2022]
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22
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GUO ZQ, XU D, WAN QH, CHEN L. Separation of Dihydroergotoxine on Polar-Embedded Reversed-Phase Stationary Phase. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2009. [DOI: 10.1016/s1872-2040(08)60086-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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23
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Bayliss MA, Venn RF, Edgington AM, Webster R, Walker DK. Determination of a potent urokinase-type plasminogen activator, UK-356,202, in plasma at pg/mL levels using column-switching HPLC and fluorescence detection. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:121-6. [DOI: 10.1016/j.jchromb.2008.11.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 11/12/2008] [Accepted: 11/14/2008] [Indexed: 10/21/2022]
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24
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Giaginis C, Tsantili-Kakoulidou A. Alternative measures of lipophilicity: from octanol-water partitioning to IAM retention. J Pharm Sci 2008; 97:2984-3004. [PMID: 18553641 DOI: 10.1002/jps.21244] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This review describes lipophilicity parameters currently used in drug design and QSAR studies. After a short historical overview, the complex nature of lipophilicity as the outcome of polar/nonpolar inter- and intramolecular interactions is analysed and considered as the background for the discussion of the different lipophilicity descriptors. The first part focuses on octanol-water partitioning of neutral and ionisable compounds, evaluates the efficiency of predictions and provides a short description of the experimental methods for the determination of distribution coefficients. A next part is dedicated to reversed-phase chromatographic techniques, HPLC and TLC in lipophilicity assessment. The two methods are evaluated for their efficiency to simulate octanol-water and the progress achieved in the refinement of suitable chromatographic conditions, in particular in the field of HPLC, is outlined. Liposomes as direct models of biological membranes are examined and phospolipophilicity is compared to the traditional lipophilicity concept. Difficulties associated with liposome-water partitioning are discussed. The last part focuses on Immobilised Artificial Membrane (IAM) chromatography as an alternative which combines membrane simulation with rapid measurements. IAM chromatographic retention is compared to octanol-water and liposome-water partitioning as well as to reversed-phase retention and its potential to predict biopartitioning and biological activities is discussed.
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Affiliation(s)
- Costas Giaginis
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 157 71, Greece
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25
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Gikas S, Tsopelas F, Giaginis C, Dimitrakopoulos J, Livadara T, Archontaki H, Tsantili-Kakoulidou A. Chromatographic behavior of zwitterionic enalapril—Exploring the conditions for lipophilicity assessment. J Pharm Biomed Anal 2008; 48:739-43. [DOI: 10.1016/j.jpba.2008.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Revised: 07/15/2008] [Accepted: 07/16/2008] [Indexed: 11/28/2022]
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26
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Bocian S, Vajda P, Felinger A, Buszewski B. Solvent excess adsorption on the stationary phases for reversed-phase liquid chromatography with polar functional groups. J Chromatogr A 2008; 1204:35-41. [PMID: 18703199 DOI: 10.1016/j.chroma.2008.07.056] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Revised: 07/11/2008] [Accepted: 07/11/2008] [Indexed: 11/18/2022]
Abstract
The measurement of acetonitrile and methanol adsorption was carried out on stationary phases with specific functionalities. The results were compared with the adsorption of those solvents on alkyl-modified adsorbents. This comparison allows us to describe the effect of polar groups on the adsorption of the organic modifiers. Our results clearly demonstrate how the functional groups modify the chromatographic properties of the homogeneous hydrophobic adsorbents.
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Affiliation(s)
- Szymon Bocian
- Department of Environmental Chemistry & Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, Gagarin 7, Torun, Poland
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27
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Rafferty JL, Siepmann JI, Schure MR. Molecular-Level Comparison of Alkylsilane and Polar-Embedded Reversed-Phase Liquid Chromatography Systems. Anal Chem 2008; 80:6214-21. [DOI: 10.1021/ac8005473] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jake L. Rafferty
- Departments of Chemistry and of Chemical Engineering and Material Science and the Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, and Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Box 0904, Spring House, Pennsylvania 19477-0904
| | - J. Ilja Siepmann
- Departments of Chemistry and of Chemical Engineering and Material Science and the Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, and Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Box 0904, Spring House, Pennsylvania 19477-0904
| | - Mark R. Schure
- Departments of Chemistry and of Chemical Engineering and Material Science and the Minnesota Supercomputing Institute, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, and Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Box 0904, Spring House, Pennsylvania 19477-0904
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28
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Wang Q, Han Y, Wang Y, Qin Y, Guo ZX. Effect of Surfactant Structure on the Stability of Carbon Nanotubes in Aqueous Solution. J Phys Chem B 2008; 112:7227-33. [DOI: 10.1021/jp711816c] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Qi Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China, and Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Yuchun Han
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China, and Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Yilin Wang
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China, and Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Yujun Qin
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China, and Department of Chemistry, Renmin University of China, Beijing 100872, China
| | - Zhi-Xin Guo
- Key Laboratory of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China, and Department of Chemistry, Renmin University of China, Beijing 100872, China
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29
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Giaginis C, Tsantili‐Kakoulidou A. Current State of the Art in HPLC Methodology for Lipophilicity Assessment of Basic Drugs. A Review. J LIQ CHROMATOGR R T 2007. [DOI: 10.1080/10826070701665626] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Costas Giaginis
- a Department of Pharmaceutical Chemistry , School of Pharmacy, University of Athens , Athens, Greece
| | - Anna Tsantili‐Kakoulidou
- a Department of Pharmaceutical Chemistry , School of Pharmacy, University of Athens , Athens, Greece
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30
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Giaginis C, Theocharis S, Tsantili-Kakoulidou A. Octanol/water partitioning simulation by reversed-phase high performance liquid chromatography for structurally diverse acidic drugs: Effect of n-octanol as mobile phase additive. J Chromatogr A 2007; 1166:116-25. [PMID: 17719594 DOI: 10.1016/j.chroma.2007.08.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 07/30/2007] [Accepted: 08/03/2007] [Indexed: 11/30/2022]
Abstract
The role of n-octanol as mobile phase additive for the lipophilicity assessment of 45 structurally diverse acidic drugs both at neutral (pH 2.5) and ionized form (pH 7.4) was investigated. Extrapolated retention factors logk(w) were determined on a BDS C18 column using methanol as organic modifier and different amounts of n-octanol as mobile phase additive. For more polar compounds, the effect of n-octanol in retention was found to decrease as their lipophilicity increased. In the case of carboxylic acids and oxicams, the differentiation in retention, in presence and absence of n-octanol, could be further attributed to the attenuation of polar interactions, concerning mainly hydrogen bonding. At pH 2.5, the use of n-octanol saturated buffer, without further addition of n-octanol in the mobile phase, led to 1:1 correlation with logP. At physiological pH, 1:1 correlation was obtained between logD(7.4) and logk(w)(oct) indices upon addition of 0.25% n-octanol, in the case of weak acids. For strongly ionized compounds, a good correlation was also established under the same conditions. The corresponding equation, however, possessed a large negative intercept and a slope lower than unity.
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Affiliation(s)
- Costas Giaginis
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 15771, Greece
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31
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Faria AM, Tonhi E, Collins KE, Collins CH. Stability studies of stationary phases from poly(methyltetradecylsiloxane) sorbed and immobilized onto metalized and unmodified silicas. J Sep Sci 2007; 30:1844-51. [PMID: 17638361 DOI: 10.1002/jssc.200700027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Stationary phases for RP-HPLC were prepared from metalized (titanized and zirconized) and unmodified silica particles using sorbed and immobilized poly(methyltetradecylsiloxane) (PMTDS). Different immobilization procedures, such as gamma irradiation and thermal treatments, were used for the preparation of the immobilized PMTDS phases. The stabilities of these stationary phases were evaluated by passing alkaline (pH 10) mobile phase through 60 mm x 3.9 mm columns of the different phases, with periodic tests to evaluate chromatographic performance. The results show that higher stabilities were obtained with stationary phases based on PMTDS immobilized on zirconized silica, these phases being 50% more stable than their titanized silica counterparts and 400% more stable than those based on unmodified silica. These supports provide higher chemical stability to the laboratory-made stationary phases, when compared with chemically bonded silica-based phases.
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Affiliation(s)
- Anizio M Faria
- Instituto de Química, Universidade Estadual de Campinas, 13084-971 Campinas, SP, Brazil
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32
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Lesellier E, West C. Description and comparison of chromatographic tests and chemometric methods for packed column classification. J Chromatogr A 2007; 1158:329-60. [PMID: 17467721 DOI: 10.1016/j.chroma.2007.03.122] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 03/27/2007] [Accepted: 03/29/2007] [Indexed: 11/26/2022]
Abstract
The main tests developed in last 20 years to investigate the chromatographic behaviour and the stationary phase properties are described in this paper. These properties are the hydrophobicity, depending on the surface area and the bonding density, the number of accessible residual silanol groups having sometimes different acidity, which can interact with neutral solutes by hydrogen bonds or with the ionic form of basic compounds and the shape or steric selectivity, depending on both the functionality of the silanising agent and the bonding density. Two types of tests are performed, either based on key solutes having well defined properties such as phenol, caffeine, amitriptyline, benzylamine, acenaphtene, o-terphenyl, triphenylene, p-ethylaniline, carotenoid pigments, or on retention models (solvation parameter, hydrophobic subtraction) obtained from the analyses of numerous and varied compounds. Thus, the chromatographic properties are either related to selectivities or retention factors calculated from key solutes, or they are described by interaction coefficients provided by multilinear regression from retention models. Three types of comparison methods are used based on these data. First, simple plots allow the study of differences between the columns as regards to one or two properties. Columns located in the same area of the plot display close properties. Second, chemometric methods such as principal component analysis (PCA) or hierarchical cluster analysis (HCA) can be performed to compare columns. In this case, all the studied properties are included in the comparison, done either by data projection to reduce the space in which the information is located (PCA) or by distance calculation and comparison for drawing a classification (HCA). Neighbouring columns are expected to provide identical chromatographic performances. These two chemometric methods can be used together, PCA before HCA. The third way is to calculate a discrimination factor from a reference column, through calculation methods based on the Pythagorean Theorem: the lower this factor, the closer the column properties. Following the presentation of the analytical conditions, the compounds and the data treatments used by the teams working in this field, the pertinence of the different selectivities, i.e. of the different probe solute couples or of the different interaction coefficients, are discussed as regards their discrimination capacity. The accuracy of chemometric treatments in the discrimination of stationary phases having different functionalities (octadecylsiloxane (ODS), cyano, fluorinated, phenyl, polar embedded group or "aqua" type) will be discussed, as well as their performances in the finer ODS discrimination. New two-dimensional plots, from data gained by different studies will be suggested, to improve the classification of stationary phases having different nature of bonded chains.
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Affiliation(s)
- E Lesellier
- ICOA, UFR Sciences, UMR CNRS 6005, B.P. 6759, rue de Chartres, 45067 Orléans cedex 2, France.
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33
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Kayillo S, Dennis GR, Shalliker RA. An assessment of the retention behaviour of polycyclic aromatic hydrocarbons on reversed phase stationary phases: Selectivity and retention on C18 and phenyl-type surfaces. J Chromatogr A 2006; 1126:283-97. [PMID: 16698029 DOI: 10.1016/j.chroma.2006.04.054] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Revised: 04/04/2006] [Accepted: 04/06/2006] [Indexed: 11/17/2022]
Abstract
In this manuscript the retention and selectivity of a set of linear and non-linear PAHs were evaluated on five different reversed-phase columns. These phases included C18 and C18 Aqua stationary phases, as well as three phenyl phases: Propyl-phenyl, Synergi polar-RP and Cosmosil 5PBB phase. Overall, the results revealed that the phenyl-type columns offered better separation performance for the linear PAHs, while the separation of the structural isomer PAHs was enhanced on the C18 columns. The Propyl-phenyl column was found to have the highest molecular-stationary phase interactions, as evidenced by the greatest rate of change in 'S' (0.71) as a function of the molecular weight in the PAH homologous series, despite having the lowest surface coverage (3% carbon load) (where S is the slope of a plot of logk versus the solvent composition). In contrast, the C18 Aqua column, having the highest surface coverage (15% carbon load) was found to have the second lowest molecular-stationary phase interactions (rate of change in S=0.61). Interestingly, the Synergi polar-RP column, which also is a phenyl stationary phase behaved more 'C18-like' than 'phenyl-like' in many of the tests undertaken. This is probably not unexpected since all five phases were reversed phase.
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Affiliation(s)
- Sindy Kayillo
- Nanoscale Organisation and Dynamics Group, University of Western Sydney, NSW 1797, Australia
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34
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Buszewski B, Gadzala-Kopiuch RM, Jaroniec M. Chromatographic Properties of Mixed Chemically Bonded Phases with Alkylamide and Aminopropyl Ligands. J LIQ CHROMATOGR R T 2006. [DOI: 10.1080/10826079708002705] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- B. Buszewski
- b Department of Environmental Chemistry , N. Copernicus University , 87100, Torun, Poland
| | - R. M. Gadzala-Kopiuch
- b Department of Environmental Chemistry , N. Copernicus University , 87100, Torun, Poland
| | - M. Jaroniec
- a Department of Chemistry , Kent State University Kent , Ohio, 44242
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35
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Jakab A, Schubert G, Prodan M, Forgacs E. PCA, FOLLOWED BY TWO-DIMENSIONAL NONLINEAR MAPPING AND CLUSTER ANALYSIS, VERSUS MULTILINEAR REGRESSION IN QSRR. J LIQ CHROMATOGR R T 2006. [DOI: 10.1081/jlc-100108535] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Annamaria Jakab
- a Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences , P. O. Box 17, 1525 , Hungary
| | - Gábor Schubert
- b Institute of Isotope and Surface Chemistry, Chemical Research Center, Hungarian Academy of Sciences , P. O. Box 77, 1525 , Hungary
| | - Miklos Prodan
- a Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences , P. O. Box 17, 1525 , Hungary
| | - Esther Forgacs
- a Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences , P. O. Box 17, 1525 , Hungary
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36
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Giaginis C, Theocharis S, Tsantili-Kakoulidou A. Contribution to the standardization of the chromatographic conditions for the lipophilicity assessment of neutral and basic drugs. Anal Chim Acta 2006; 573-574:311-8. [PMID: 17723539 DOI: 10.1016/j.aca.2006.03.074] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 03/16/2006] [Accepted: 03/22/2006] [Indexed: 11/26/2022]
Abstract
The chromatographic conditions aiming to a better simulation of n-octanol-water partitioning using a base deactivated silica (BDS) column as stationary phase were investigated for structurally diverse basic and neutral drugs. Extrapolated retention factors log k(w), determined using different methanol fractions as organic modifier, were considered as lipophilicity indices. The effect of n-decylamine and n-octanol as mobile phase additives was examined and the appropriateness of the final retention outcome to reproduce lipophilicity data was evaluated. Moreover, the influence of n-octanol on the linearity of the log k/methanol fraction relationship and on the uniformity of the retention mechanism was investigated. 1:1 correlation between log k(w) values and the logarithm of the distribution coefficient (logD) was established for basic drugs in presence of both n-decylamine and n-octanol as mobile phase additives. However, for neutral drugs n-decylamine proved to be a sufficient and more important factor than n-octanol.
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Affiliation(s)
- Costas Giaginis
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of Athens, Panepistimiopolis, Zografou, Athens 15771, Greece
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37
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Silva RB, Silva CR, Airoldi C, Collins CH, Jardim ICS. Preparation and characterization of a new HPLC C18 reversed phase containing thiocarbamate groups. Microchem J 2006. [DOI: 10.1016/j.microc.2006.01.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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38
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Lesellier E, West C, Tchapla A. Classification of special octadecyl-bonded phases by the carotenoid test. J Chromatogr A 2006; 1111:62-70. [PMID: 16472818 DOI: 10.1016/j.chroma.2006.01.107] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Revised: 01/17/2006] [Accepted: 01/24/2006] [Indexed: 10/25/2022]
Abstract
Amongst the numerous base-deactivated ODS phases obtained by increasing the bonding density or/and by efficient endcapping treatments, some particular stationary phases have been developed, to limit the additional interactions of basic compounds with residual silanols, to work at extreme pH or with rich water mobile phases. Horizontal polymeric phases, sterically protected ones, hybrid silicas, propylene bridge, are particularly used for this purpose. Octadecyl chains with embedded polar groups and hydrophilic endcapping are also used in this goal. The properties of these phases were studied with a simple test consisting in the injection of carotenoid pigments in Subcritical Fluid Chromatography. The molecules used and the nature of the mobile phase allow the determination of hydrophobicity, polar site accessibility and type or/and bonding density of the stationary phases. Whatever the type of the phases, the particular stationary phases do not show any remarkable property, in comparison to other base-deactivated C18-bonded phases. On the other hand, embedded and polar-endcapped phases display a specific behaviour in regard of hydrophilic interactions, which are highlighted by the absence of water in the subcritical fluid. Additional properties of these phases are described, such as steric recognition and retention performances. As expected, polar-embedded phases are less retentive than classical ODS ones, but are sometimes able to provide greater steric recognition. On the other hand, the polar-endcapped phases display greater hydrophobicity than polar-embedded ones. From a simple classification diagram based on chromatographic properties, differences can be noticed between the polar-embedded groups (amide, carbamate, ether, sulfonamide) and between embedded and endcapped phases. Surprising behaviours are also noticed for some on the tested phases.
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Affiliation(s)
- E Lesellier
- LETIAM, Groupe de Chimie Analytique de Paris Sud (EA 3343), IUT d'Orsay, Plateau du Moulon, Orsay, France.
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39
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Liu X, Tanaka H, Yamauchi A, Testa B, Chuman H. Determination of lipophilicity by reversed-phase high-performance liquid chromatography. J Chromatogr A 2005; 1091:51-9. [PMID: 16395792 DOI: 10.1016/j.chroma.2005.07.029] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipophilicity was evaluated using a novel RP-HPLC stationary phase (Discovery-RP-Amide-C16) with and without 1-octanol added to the mobile phase. A set of 46 drugs and flavonoids characterized by a broad structural diversity and a wide log Poct range (-0.69 to 5.70) was selected for this study. This set consists of neutral solutes and solutes with acidic or ampholytic functionalities which were maintained neutral at pH 2.5 or 4. In our conditions, the addition of 1-octanol in the mobile phase proved a key factor to derive a lipophilicity index log k(w) highly correlated with log Poct for all investigated solutes. 1-Octanol improved the correlation between log Poct and log k(w) mainly by influencing the retention behavior of the solutes with log Poct values below +3. This study brings additional evidence that under proper experimental conditions of stationary and mobile phases, RP-HPLC is a very useful method to obtain log Poct values.
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Affiliation(s)
- Xiangli Liu
- Institute of Health Biosciences, The University of Tokushima Graduate School, Shomachi, Tokushima 770-8505, Japan.
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40
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Euerby MR, Petersson P. Chromatographic classification and comparison of commercially available reversed-phase liquid chromatographic columns containing polar embedded groups/amino endcappings using principal component analysis. J Chromatogr A 2005; 1088:1-15. [PMID: 16130727 DOI: 10.1016/j.chroma.2004.10.027] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polar embedded phases have become increasingly popular in liquid chromatography (LC) analysis. These phases can produce diverse chromatographic selectivities as a result of their differing base silica, the type of polar embedded group (i.e. amide, urea, carbamate, ether or sulphonamide moieties) and the length of the alkyl ligand. Four column characterization protocols, using differing test probes, have been used to characterize 18 of these phases together with 17 alkyl phases (some of which contained novel polar endcapping, i.e. amino), which have been evaluated using principal component analysis (PCA). PCA provided graphical comparisons of the differences/similarities between these phases and between their corresponding C-alkyl, amino endcapped and enhanced polar selectivity phases.
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Affiliation(s)
- Melvin R Euerby
- AstraZeneca R&D Charnwood, Analytical Development, Pharmaceutical and Analytical R&D-Charnwood/Lund, Loughborough, Leicestershire, UK.
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41
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Abstract
The aim of the work was to find the relationship between the structure of the stationary phase and the velocity of the electroosmotic flow (EOF) that it can generate. The attention was paid to the dependence of the electroosmotic mobility (microEOF) on such parameters as: (i) coverage density of a series of specially synthesized C18 stationary phases with/without end-capping, with monomeric/polymeric architecture; (ii) the length of the alkyl chain in the alkylamide (AP) bonded phase (the phases studied were AP with: C1, C5, C6, C7, C8, C12 and C18 alkyl chains) and the effect of the presence of amide and residual amine groups; (iii) the effect of the mobile phase composition on the EOF; (iv) the effect of pH on the EOF. The obtained results have shown that there is no direct relationship between silanol activity (Galushko test) and electroosmotic mobility for C18 phases. The deterioration of the EOF has been observed for AP phases at high pH values. This effect has been attributed to the presence of hydrolytic pillow, which is connected with the sorption of water from hydro-organic mobile phases.
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Affiliation(s)
- Michał Szumski
- Department of Environmental Chemistry and Ecoanalytics, Faculty of Chemistry, Nicolas Copernicus University, 7 Gagarin Street, 87-100 Toruń, Poland
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42
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Silva CR, Collins CH, Jardim ICSF, Airoldi C. Chromatographic and column stability at pH 7 of a C18 dimethylurea polar stationary phase. J Chromatogr A 2004; 1030:157-66. [PMID: 15043265 DOI: 10.1016/j.chroma.2003.11.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Chromatographic evaluations of a C18 dimethylurea phase in 150 mm x 3.9 mm HPLC columns were performed using the Tanaka and Engelhardt test mixtures. The applicability of the new C18 dimethylurea phase was also evaluated with a mixture of some herbicides and their metabolites. An artificial aging procedure was also performed by passing a potassium phosphate mobile phase buffered at pH 7.0 through C18 50 mm x 3.9 mm dimethylurea columns. The column stability was evaluated by means of the chromatographic parameters obtained for the separation of some compounds from the Neue test mixture, using apolar, polar and highly basic analytes.
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Affiliation(s)
- César Ricardo Silva
- Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13083-970 Campinas, São Paulo, Brazil
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43
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Lopes NP, Collins KE, Jardim ICSF. Microwave-immobilized polybutadiene stationary phase for reversed-phase high-performance liquid chromatography. J Chromatogr A 2004; 1030:225-9. [PMID: 15043273 DOI: 10.1016/j.chroma.2003.09.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Polybutadiene (PBD) has been immobilized on high-performance liquid chromatography (HPLC) silica by microwave radiation at various power levels (52-663 W) and actuation times (3-60 min). Columns prepared from these reversed-phase HPLC materials, as well as from similar non-irradiated materials, were tested with standard sample mixtures and characterized by elemental analysis (%C) and infrared spectroscopy. A microwave irradiation of 20 min at 663 W gives a layer of immobilized PBD that presented good performance. Longer irradiation times give thicker immobilized layers having less favorable chromatographic properties.
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Affiliation(s)
- Nilva P Lopes
- Laboratório de Pesquisas em Cromatografia Líquida, LABCROM, Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, CEP 13084-971 Campinas, SP, Brazil
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44
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Gadzała-Kopciuch R, Buszewski B. A comparative study of hydrophobicity of octadecyl and alkylamide bonded phases based on methylene selectivity. J Sep Sci 2003. [DOI: 10.1002/jssc.200301428] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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45
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McCalley DV. Selection of suitable stationary phases and optimum conditions for their application in the separation of basic compounds by reversed-phase HPLC. J Sep Sci 2003. [DOI: 10.1002/jssc.200390026] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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46
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Taillardat-Bertschinger A, Carrupt PA, Barbato F, Testa B. Immobilized artificial membrane HPLC in drug research. J Med Chem 2003; 46:655-65. [PMID: 12593643 DOI: 10.1021/jm020265j] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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47
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Silva CR, Jardim ICSF, Airoldi C. New generation of sterically protected C18 stationary phases containing embedded urea groups for use in high-performance liquid chromatography. J Chromatogr A 2003; 987:127-38. [PMID: 12613805 DOI: 10.1016/s0021-9673(02)01807-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
New monofunctional C18 urea stationary phases with sterically protecting dimethyl and diisopropyl groups were prepared by a single step modification process. ProntoSil spherical silica (3 microm) was chemically modified with the monofunctional ethoxysilanes, [(3-octadecylurea)propyl]dimethyl and [(3-octadecylurea)propyl]diisopropyl ethoxysilanes. The phases were characterized by elemental analysis, infrared and solid-state 29Si and 13C NMR spectroscopies. Chromatographic characterizations of the new phases in 50x3.9 mm HPLC columns were performed by the separation of two different test mixtures, containing nonpolar, polar and highly basic compounds.
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Affiliation(s)
- César Ricardo Silva
- Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13083-970 Campinas, São Paulo, Brazil
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Silva CR, Jardim ICSF, Airoldi C. Evaluation of the applicability and the stability of a C18 stationary phase containing embedded urea groups. J Chromatogr A 2003; 987:139-46. [PMID: 12613806 DOI: 10.1016/s0021-9673(02)01947-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chromatographic evaluations of a new C18 urea phase in 150x3.9 mm HPLC columns, involving the separation of different test mixtures, indicate good performance for both polar and basic compounds when compared with a commercial C18 reversed phase and also show promising results for the separation of some herbicides. An aging study was performed by passing a potassium phosphate mobile phase buffered at pH 7 through 50x3.9 mm HPLC columns. The column stability was evaluated by means of the chromatographic parameters obtained for the separation of some compounds of the Neue test mixture, containing apolar, polar and highly basic analytes. The applicability of the new C18 urea phase was evaluated with a herbicide mixture.
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Affiliation(s)
- César Ricardo Silva
- Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13083-970 Campinas, SP, Brazil
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49
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Jakab A, Schubert G, Prodan M, Forgács E. Determination of the retention behavior of barbituric acid derivatives in reversed-phase high-performance liquid chromatography by using quantitative structure-retention relationships. J Chromatogr B Analyt Technol Biomed Life Sci 2002; 770:227-36. [PMID: 12013230 DOI: 10.1016/s1570-0232(01)00596-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Retention parameters of 45 barbituric acid derivatives were determined on an amide embedded RP silica column using non-buffered water-dioxan eluent systems. Linear correlations were calculated between the logarithm of the capacity factor and the dioxan concentration in the eluent. Six different retention parameters of each barbituric acid derivative were correlated with different conventional and quantum chemical structural descriptors using quantitative structure-retention relationship (QSRR). The different parameters were: intercept (log k0) and slope (b) values of the linear, the combined retention parameter (log k0/b), asymmetry factor (AF5) and theoretical plate values (N(USP) and N(JP), according to the United States and Japanese Pharmacopoeia calculations). Stepwise regression analysis (SRA) and principal component analysis (PCA) followed by two-dimensional nonlinear mapping were used to determine the retention behavior of barbituric acid derivatives. SRA and PCA led to similar results. The results indicated that the retention of barbituric acid derivatives are mainly governed by the polaric and steric parameters of the substituents.
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Affiliation(s)
- Annamaria Jakab
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest.
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50
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Jakab A, Prodan M, Forgács E. Influence of physico-chemical parameters of some barbituric acid derivatives on their retention on an amide embedded RP silica column. J Pharm Biomed Anal 2002; 27:913-21. [PMID: 11836055 DOI: 10.1016/s0731-7085(01)00629-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Retention parameters of 45 different barbituric acid derivatives were determined on an amide embedded RP silica column (Discovery RP-AmideC16) using non-buffered water-acetonitrile eluent systems. Linear correlation were calculated between the logarithm of the capacity factor and the acetonitrile concentration in the eluent. To determine the retention behavior of barbituric acid derivatives, stepwise regression analysis (SRA) and principal component analysis (PCA) followed by two-dimensional nonlinear and modified nonlinear mapping was used. It can be concluded, the retention of barbituric acid derivatives are governed mainly by the steric parameters of the substituents. Principal component analysis indicated that the barbituric acid derivatives have mixed retention on this amide embedded RP silica column in water-acetonitrile eluent.
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Affiliation(s)
- Annamaria Jakab
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, PO Box 17, 1525, Budapest, Hungary.
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