1
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Paulo G, Bartolomé L, Bondarchuk O, Meloni S, Grosu Y, Giacomello A. Partial Water Intrusion and Extrusion in Hydrophobic Nanopores for Thermomechanical Energy Dissipation. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2024; 128:12036-12045. [PMID: 39081555 PMCID: PMC11284848 DOI: 10.1021/acs.jpcc.4c02900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/02/2024] [Revised: 06/25/2024] [Accepted: 06/27/2024] [Indexed: 08/02/2024]
Abstract
Forced wetting (intrusion) and spontaneous dewetting (extrusion) of hydrophobic/lyophobic nanoporous materials by water/nonwetting liquid are of great importance for a broad span of technological and natural systems such as shock-absorbers, molecular springs, separation, chromatography, ion channels, nanofluidics, and many more. In most of these cases, the process of intrusion-extrusion is not complete due to the stochastic nature of external stimuli under realistic operational conditions. However, understanding of these partial processes is limited, as most of the works are focused on an idealized complete intrusion-extrusion cycle. In this work, we show an experimental system operating under partial intrusion/extrusion conditions and present a simple model that captures its main features. We rationalize these operational conditions in terms of the pore entrance and cavity size distributions of the material, which control the range of intrusion/extrusion pressures.
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Affiliation(s)
- Gonçalo Paulo
- Dipartimento
di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, 00184 Rome, Italy
| | - Luis Bartolomé
- Centre
for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), 01510 Álava, Spain
| | - Oleksandr Bondarchuk
- International
Iberian Nanotechnology Laboratory, 4715-330 Braga, Portugal
- SPIN-LAB
Centre for microscopic research on matter, University of Silesia in Katowice, 75 Pułku Piechoty 1A St., bldg J, 41-500 Chorzów, Poland
- Institute
of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
| | - Simone Meloni
- Dipartimento
di Scienze chimiche, farmaceutiche ed agrarie, Università degli Studi di Ferrara, 44121 Ferrara, Italy
| | - Yaroslav Grosu
- Centre
for Cooperative Research on Alternative Energies (CIC energiGUNE), Basque Research and Technology Alliance (BRTA), 01510 Álava, Spain
- Institute
of Chemistry, University of Silesia in Katowice, Szkolna 9, 40-006 Katowice, Poland
| | - Alberto Giacomello
- Dipartimento
di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, 00184 Rome, Italy
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2
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Cheng XD, Zhang Z, Dai XX, Li YP. Retention behavior of nucleosides and nucleobases on a 3 μm undecylenic acid-functionalized silica column in per aqueous liquid chromatography and hydrophilic interaction liquid chromatography separation modes. J Chromatogr A 2024; 1721:464833. [PMID: 38555828 DOI: 10.1016/j.chroma.2024.464833] [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: 01/20/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024]
Abstract
A 3 μm undecylenic acid-functionalized stationary phase (UAS) was prepared for the separation of nucleosides and nucleobases using per aqueous liquid chromatography (PALC) and hydrophilic interaction liquid chromatography (HILIC). The retention behaviors of nucleosides and nucleobases in PALC and HILIC modes were explored by adjusting parameters such as water content, buffer concentration, pH of the mobile phase and column temperature. The experimental data and separation chromatogram demonstrated that PALC could provide retention comparable to that of HILIC for nucleosides and nucleobases. Comparative studies using diluted adenosine solutions evaluated theoretical plates and peak shape for the same retention factors (between 0.25 and 5.0) in PALC and HILIC. There was no buffer component in the mobile phases used to operate the comparisons. HILIC mode is more efficient for adenosine than PALC mode at low retention factors. It's the exact opposite phenomenon for high retention factors. It is proposed that the mass transfer of adenosine between the UAS, the water-rich layer and the ACN-rich mobile phase in HILIC is relatively slow. Given the significant use of toxic ACN in HILIC, PALC emerges as a safer and more effective alternative for separating nucleosides and nucleobases.
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Affiliation(s)
- Xiao-Dong Cheng
- School of Chemistry and Chemical Engineering, Qiannan Normal University for Nationalities, Duyun 558000, China.
| | - Zheng Zhang
- Wuhan Prevention and Treatment Center for Occupational Diseases, Wuhan 430015, China; Department of Biochemistry, Purdue University, West Lafayette, IN, USA
| | - Xue-Xin Dai
- School of Chemistry and Chemical Engineering, Qiannan Normal University for Nationalities, Duyun 558000, China
| | - Yun-Ping Li
- School of Chemistry and Chemical Engineering, Qiannan Normal University for Nationalities, Duyun 558000, China
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3
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Gritti F, Lawrence N, Field J. Preparation and investigation of two-component silica-modified hydrophobic layer for minimizing retention loss of reversed-phase chromatographic columns using fully aqueous mobile phases. J Chromatogr A 2024; 1719:464766. [PMID: 38428339 DOI: 10.1016/j.chroma.2024.464766] [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: 01/09/2024] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 03/03/2024]
Abstract
Chromatographers often employ fully aqueous mobile phases to retain highly polar compounds in reversed-phase liquid chromatography (RPLC). However, when the flow rate is interrupted, either accidentally or intentionally, a substantial loss in retention occurs due to the spontaneous dewetting of water from the hydrophobic surface of conventional RPLC-C18 particles. Previous studies have shown that maintaining a low C18 surface coverage (approximately 1.5 μmol/m2) can mitigate water dewetting by increasing chain disorder, facilitating the intercalation of water clusters between the C18-bonded chains, and keeping the mesopores wetted. In this research, we explore the potential and additional benefits of using two-component surface bonding materials (C8/C18 and PhenylHexyl (PhHx)/C18) at a constant and low total surface coverage of 1.51 ± 0.15 μmol/m2. We synthesized seven one- and two-component modified silica particles with a volume average particle size of 5.22 μm and an average mesopore size of 104 Å. The surface coverage was increased from 0 to 0.54, 1.00, and to 1.66 μmol2 for C8 chains and from 0 to 0.52, 0.70, and to 1.65 μmol2 for PhHx ligands. To prevent interactions between water and any unreacted silanols, all seven derivatized particles were heavily endcapped with trimethylsilane (TMS) reagent. The fraction of the surface area remaining in contact with water was determined by measuring the retention times of weakly (thiourea) and strongly (thymine) retained compounds at intervals of 1, 2, 4, 8, 16, 32, and 64 minutes following the cessation of flow. Two distinct column temperatures, 24°C and 60°C, were employed in the experiments. Retention losses were found to be minimized in the presence of a small quantity of C8 chains (less than 40% of the total surface coverage). Additionally, it is essential to consider substantial fractions of PhHx chains, as long as the presence of the PhHx ligand does not significantly impact retention and selectivity. Combining mixed RPLC bondings with a low total surface coverage of approximately 1.5 μmol/m2 emerges as a viable solution for further minimizing retention loss in standard C18-bonded RPLC columns, particularly within the surface coverage range of 2.5-3.0 μmol/m2.
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Affiliation(s)
- Fabrice Gritti
- Waters Corporation, Instrument/Core Research/Fundamental, 34 Maple Street, Milford, MA, 01757, USA.
| | - Nicole Lawrence
- Waters Corporation, Instrument/Core Research/Fundamental, 34 Maple Street, Milford, MA, 01757, USA
| | - Jessica Field
- Waters Corporation, Instrument/Core Research/Fundamental, 34 Maple Street, Milford, MA, 01757, USA
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4
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Dembek M, Bacskay I, Buratti A, Catani M, Felinger A, Buszewski B, Bocian S. Retention mechanism on phosphodiester stationary phases in hydrophilic interaction liquid chromatography and purely aqueous mobile phase part II: Overloading with limited soluble samples. J Chromatogr A 2024; 1715:464596. [PMID: 38159406 DOI: 10.1016/j.chroma.2023.464596] [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: 08/31/2023] [Revised: 12/13/2023] [Accepted: 12/19/2023] [Indexed: 01/03/2024]
Abstract
The adsorption behaviour of caffeine and theophylline under hydrophilic interaction chromatography and purely aqueous conditions was investigated on four phosphodiester stationary phases. Solute adsorption isotherms were determined by frontal analysis or inverse method. The bi-Langmuir model was found to be the best choice to describe the behaviour of caffeine and theophylline adsorption in purely aqueous conditions, whereas the bi-Moreau model describes the adsorption phenomena in HILIC conditions. The results obtained demonstrate that the interaction of caffeine and theophylline with the stationary phase surface varies depending on the mobile phase composition. Both in pure aqueous mobile phase and in HILIC mode, the heterogeneity of the surface of the studied stationary phases is confirmed. In hydrophilic solutions, the sample molecules interact with the stationary phase only. In hydrophobic conditions, a lateral interaction occurs between caffeine or theophylline molecules, which are poorly soluble in acetonitrile-rich solvents. This confirms that the same compound on the same stationary phase can behave rather differently, depending on the mobile phase composition. Thus, the mobile phase may govern and control the retention mechanism.
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Affiliation(s)
- Mikołaj Dembek
- Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarin St., Toruń PL-87-100, Poland
| | - Ivett Bacskay
- HUN-REN-PTE Molecular Interactions in Separation Science Research Group, Ifjúság útja 6, Pécs H-7624, Hungary; Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, Pécs H-7624, Hungary
| | - Alessandro Buratti
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Martina Catani
- Department of Chemical, Pharmaceutical and Agricultural Sciences, University of Ferrara, via L. Borsari 46, Ferrara 44121, Italy
| | - Attila Felinger
- HUN-REN-PTE Molecular Interactions in Separation Science Research Group, Ifjúság útja 6, Pécs H-7624, Hungary; Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, Pécs H-7624, Hungary; Institute of Bioanalysis, Medical School, University of Pécs, Szigeti út, Pécs H-7624, Hungary
| | - Bogusław Buszewski
- Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarin St., Toruń PL-87-100, Poland
| | - Szymon Bocian
- Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarin St., Toruń PL-87-100, Poland; Department of Analytical and Environmental Chemistry and Szentágothai Research Center, University of Pécs, Ifjúság útja 6, Pécs H-7624, Hungary.
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5
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Trespi S, Mazzotti M. HPLC method development for the quantification of a mixture of reacting species: The case of lactose. J Chromatogr A 2024; 1715:464553. [PMID: 38159403 DOI: 10.1016/j.chroma.2023.464553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/28/2023] [Accepted: 11/30/2023] [Indexed: 01/03/2024]
Abstract
Preparative and analytical chromatography are impaired by analytes that undergo a chemical reaction during the chromatographic separation, leading to peak distortion and systematic errors during the subsequent quantification phase. The pitfalls are highlighted through a combination of analytical results and numerical simulations. Two different quantification strategies for partially overlapping and reacting peaks are compared. A novel method development strategy based on the valley-to-peak ratio instead of the more common resolution is proposed. The method has been used to experimentally investigate the chromatographic behavior of a mutarotating sugar, lactose. The separation of the unprotected lactose isomers, α and β, has been optimized using a C18 column and pure water as the mobile phase. Phase dewetting phenomena during method development have also been studied and discussed.
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Affiliation(s)
- Silvio Trespi
- Institute of Energy and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland
| | - Marco Mazzotti
- Institute of Energy and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
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6
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Giacomello A. What keeps nanopores boiling. J Chem Phys 2023; 159:110902. [PMID: 37724724 DOI: 10.1063/5.0167530] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/29/2023] [Indexed: 09/21/2023] Open
Abstract
The liquid-to-vapor transition can occur under unexpected conditions in nanopores, opening the door to fundamental questions and new technologies. The physics of boiling in confinement is progressively introduced, starting from classical nucleation theory, passing through nanoscale effects, and terminating with the material and external parameters that affect the boiling conditions. The relevance of boiling in specific nanoconfined systems is discussed, focusing on heterogeneous lyophobic systems, chromatographic columns, and ion channels. The current level of control of boiling in nanopores enabled by microporous materials such as metal organic frameworks and biological nanopores paves the way to thrilling theoretical challenges and to new technological opportunities in the fields of energy, neuromorphic computing, and sensing.
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Affiliation(s)
- Alberto Giacomello
- Dipartimento di Ingegneria Meccanica e Aerospaziale, Sapienza Università di Roma, 00184 Rome, Italy
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7
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Lenčo J, Jadeja S, Naplekov DK, Krokhin OV, Khalikova MA, Chocholouš P, Urban J, Broeckhoven K, Nováková L, Švec F. Reversed-Phase Liquid Chromatography of Peptides for Bottom-Up Proteomics: A Tutorial. J Proteome Res 2022; 21:2846-2892. [PMID: 36355445 DOI: 10.1021/acs.jproteome.2c00407] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The performance of the current bottom-up liquid chromatography hyphenated with mass spectrometry (LC-MS) analyses has undoubtedly been fueled by spectacular progress in mass spectrometry. It is thus not surprising that the MS instrument attracts the most attention during LC-MS method development, whereas optimizing conditions for peptide separation using reversed-phase liquid chromatography (RPLC) remains somewhat in its shadow. Consequently, the wisdom of the fundaments of chromatography is slowly vanishing from some laboratories. However, the full potential of advanced MS instruments cannot be achieved without highly efficient RPLC. This is impossible to attain without understanding fundamental processes in the chromatographic system and the properties of peptides important for their chromatographic behavior. We wrote this tutorial intending to give practitioners an overview of critical aspects of peptide separation using RPLC to facilitate setting the LC parameters so that they can leverage the full capabilities of their MS instruments. After briefly introducing the gradient separation of peptides, we discuss their properties that affect the quality of LC-MS chromatograms the most. Next, we address the in-column and extra-column broadening. The last section is devoted to key parameters of LC-MS methods. We also extracted trends in practice from recent bottom-up proteomics studies and correlated them with the current knowledge on peptide RPLC separation.
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Affiliation(s)
- Juraj Lenčo
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Siddharth Jadeja
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Denis K Naplekov
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Oleg V Krokhin
- Department of Internal Medicine, Manitoba Centre for Proteomics and Systems Biology, University of Manitoba, 799 JBRC, 715 McDermot Avenue, WinnipegR3E 3P4, Manitoba, Canada
| | - Maria A Khalikova
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Petr Chocholouš
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - Jiří Urban
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00Brno, Czech Republic
| | - Ken Broeckhoven
- Department of Chemical Engineering (CHIS), Faculty of Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050Brussel, Belgium
| | - Lucie Nováková
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
| | - František Švec
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 05Hradec Králové, Czech Republic
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8
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Wilson KM, Danielson ND. Micellar and sub-micellar chromatography with a cocamidopropyl betaine surfactant. J Chromatogr A 2022; 1681:463442. [DOI: 10.1016/j.chroma.2022.463442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 11/29/2022]
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9
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Retention modeling and adsorption mechanisms in reversed-phase liquid chromatography. J Chromatogr A 2021; 1662:462736. [PMID: 34923304 DOI: 10.1016/j.chroma.2021.462736] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 12/02/2021] [Accepted: 12/04/2021] [Indexed: 12/22/2022]
Abstract
To interpret the dependence of solute retention behavior on modifier content in reversed-phase liquid chromatography, a theoretical framework, based on the concentration dependence of solvophobic forces imposed on solutes and the competitive adsorptions of solutes and solvent modifiers, was proposed. The generality of the developed model was demonstrated by comparing the model with conventional retention models. The linear dependence of the Gibbs energy change of solute adsorption with respect to the modifier concentration was assumed, and the model was fitted to the experimental results, with good agreement demonstrated between the experimental data and the model. Retention behaviors were inferred to be determined by two key dimensionless groups that represented the reductions in the retention factors resulting from a weakened solvophobic interaction and modifier competitive adsorption. The retention behaviors were successfully deconvoluted for each contribution as a function of the modifier concentration by using the fitted parameters. The effects of both contributions on the retention behaviors were enhanced for the solutes with aromatic groups. The standard Gibbs energy change SLo of benzene adsorption was found to depend linearly on the number of modifier molecules present but independent of modifier identity. For the solutes associated with hydrogen-bonding groups, the degree of reduction in the solvophobic interactions was considerably reduced. Hence, the relative contributions of both mechanisms to solute retention depend greatly on the solute structure. Perturbation method was performed to investigate the modifier adsorption mechanisms. The results show that the standard Gibbs energy change SLo for the first-layer adsorption of modifiers changed linearly with the carbon number of modifier molecule. These results demonstrated that the proposed model can offer a physically consistent quantitative description of retention when solvent composition is varied.
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10
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Tsiasioti A, Zotou AS, Tzanavaras PD. Single run analysis of glutathione and its disulfide in food samples by liquid chromatography coupled to on-line post-column derivatization. Food Chem 2021; 361:130173. [PMID: 34062455 DOI: 10.1016/j.foodchem.2021.130173] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/16/2021] [Accepted: 05/18/2021] [Indexed: 10/21/2022]
Abstract
Glutathione and its disulfide were determined in a single run using liquid chromatography with on-line post-column derivatization and fluorimetric detection (340 nm/425 nm). The analytes were separated using a reversed-phase column capable of operating at 100% aqueous mobile phase and detected following direct on-line reaction with o-phthalaldehyde (7.5 mmol L-1) in highly basic medium (0.37 mol L-1 NaOH). The instrumental and chemical variables were carefully investigated towards high sensitivity and throughput, while special attention was paid to validating potential matrix effects. Glutathione and its disulfide could be selectively determined with respective LODs of 0.10 and 0.30 μmol L-1 in the absence of matrix effect (<6%). The endogenous content of the analytes was accurately determined in various food samples with recoveries ranging between 80 and 120% in all cases. The proposed method is reliable and promising as a generic analytical tool for the convenient estimation of the redox status of glutathione in various food matrices.
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Affiliation(s)
- Apostolia Tsiasioti
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124, Greece
| | - Anastasia-Stella Zotou
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124, Greece
| | - Paraskevas D Tzanavaras
- Laboratory of Analytical Chemistry, School of Chemistry, Faculty of Sciences, Aristotle University of Thessaloniki, GR-54124, Greece.
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11
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Gritti F, Walter TH. Retention Loss of Reversed-Phase Columns Using Highly Aqueous Mobile Phases: Fundamentals, Mechanism, and Practical Solutions. LCGC NORTH AMERICA 2021. [DOI: 10.56530/lcgc.na.zm6986c6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We investigate a phenomenon observed by many practitioners of reversed- phase LC: a dramatic loss in retention volume or time after the column flow is stopped and resumed when using highly aqueous mobile phases with certain columns.
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12
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den Uijl MJ, Schoenmakers PJ, Pirok BWJ, van Bommel MR. Recent applications of retention modelling in liquid chromatography. J Sep Sci 2020; 44:88-114. [PMID: 33058527 PMCID: PMC7821232 DOI: 10.1002/jssc.202000905] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/02/2020] [Accepted: 10/12/2020] [Indexed: 11/18/2022]
Abstract
Recent applications of retention modelling in liquid chromatography (2015–2020) are comprehensively reviewed. The fundamentals of the field, which date back much longer, are summarized. Retention modeling is used in retention‐mechanism studies, for determining physical parameters, such as lipophilicity, and for various more‐practical purposes, including method development and optimization, method transfer, and stationary‐phase characterization and comparison. The review focusses on the effects of mobile‐phase composition on retention, but other variables and novel models to describe their effects are also considered. The five most‐common models are addressed in detail, i.e. the log‐linear (linear‐solvent‐strength) model, the quadratic model, the log–log (adsorption) model, the mixed‐mode model, and the Neue–Kuss model. Isocratic and gradient‐elution methods are considered for determining model parameters and the evaluation and validation of fitted models is discussed. Strategies in which retention models are applied for developing and optimizing one‐ and two‐dimensional liquid chromatographic separations are discussed. The review culminates in some overall conclusions and several concrete recommendations.
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Affiliation(s)
- Mimi J den Uijl
- Analytical Chemistry Group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
| | - Peter J Schoenmakers
- Analytical Chemistry Group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
| | - Bob W J Pirok
- Analytical Chemistry Group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands
| | - Maarten R van Bommel
- Analytical Chemistry Group, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands.,Centre for Analytical Sciences Amsterdam (CASA), Amsterdam, The Netherlands.,University of Amsterdam, Faculty of Humanities, Conservation and Restoration of Cultural Heritage, Amsterdam, The Netherlands
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13
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Shin D, Kang HS, Kim H, Moon G. Multi-Class Determination of 64 Illicit Compounds in Dietary Supplements Using Liquid Chromatography-Tandem Mass Spectrometry. Molecules 2020; 25:E4399. [PMID: 32987895 PMCID: PMC7583945 DOI: 10.3390/molecules25194399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/14/2020] [Accepted: 09/17/2020] [Indexed: 11/16/2022] Open
Abstract
In this work, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for screening and confirmation of 64 illicit compounds in dietary supplements. The target compounds were illegally used pharmaceutical drugs, prohibited compounds, and not authorized ingredients for different therapeutics (sexual enhancement, weight loss, muscular strengthening, and relaxing products). The validation procedure was performed to evaluate selectivity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, and precision according to the Association of Official Analytical Chemists guidelines. The linearity was >0.98 in the range of 0.5-200 µg L-1. The LOQs were in the range 1-10 µg kg-1 for all target compounds. The accuracy (expressed as recovery) was 78.5-114%. The precision (expressed as the relative standard deviation) was below 9.15%. The developed method was applied for the determination of illicit compounds in dietary supplements collected from websites. As a result, the total detection rate was 13.5% (27 samples detected in 200 samples). The concentrations of detected samples ranged from 0.51 to 226 mg g-1. The proposed methodology is suitable for monitoring the adulteration of illicit compounds in dietary supplements.
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Affiliation(s)
| | - Hui-Seung Kang
- New Hazardous Substances Division, Department of Food Safety Evaluation, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Osong, Cheongju 28159, Korea; (D.S.); (H.K.); (G.M.)
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14
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Chester TL. The combination of partition, size exclusion, and hydrodynamic models in chromatography, and application to bonded phases on porous supports. J Chromatogr A 2020; 1620:461011. [PMID: 32284152 DOI: 10.1016/j.chroma.2020.461011] [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: 01/14/2020] [Revised: 03/02/2020] [Accepted: 03/05/2020] [Indexed: 11/26/2022]
Abstract
Liquid-liquid partition chromatography has been used for many years as a model and teaching introduction to column chromatography. However, the partition model does not describe separations on bonded phases with porous supports particularly well, especially regarding the thermodynamics controlling solute distribution. Further difficulties arise when more than one mechanism is involved in solute retention. Nomenclature is not perfectly aligned with the underlying thermodynamic descriptors and is inconsistently applied over various chromatographic techniques. Presented here is a general description of retention that spans partition, size exclusion, and hydrodynamic separation processes, and is then applied to bonded-phase separations on porous supports. The model provides a general description applicable to adsorption, reversed-phase, hydrophilic interaction, size-exclusion, hydrodynamic chromatography, and any combination of these techniques including liquid chromatography at the critical condition. Further expansion to include retention by ion-exchange and field-flow fractionation appears to be possible. Recommendations on retention factor definition and evaluation are given.
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Affiliation(s)
- T L Chester
- Department of Chemistry, University of Cincinnati, PO Box 210172, Cincinnati, Ohio 45221-0172, United States.
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Study of the Oxidative Forced Degradation of Glutathione in Its Nutraceutical Formulations Using Zone Fluidics and Green Liquid Chromatography. SEPARATIONS 2020. [DOI: 10.3390/separations7010016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In the present study, we report the results of our investigation of the oxidative forced degradation of glutathione in its nutraceutical formulations by two validated analytical methods. The first is based on the reaction of glutathione with o-phthalaldehyde through an automated zone fluidics flow platform and fluorimetric detection (λex/λem = 340/425 nm). The second is based on the separation of glutathione and its oxidation product by a green reversed-phase HPLC method coupled to direct UV detection, at 210 nm. A solution of 3% w/v H2O2 provided fast oxidation of more than 95% of glutathione to yield oxidized glutathione in a time period of 180 min. The mechanism of the oxidation was proved to follow pseudo-first order kinetics. The k, t90 and t1/2 values were calculated.
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