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Kirchkeszner C, Petrovics N, Széles A, Koshman Y, Szabó BS, Nyiri Z, Novák M, Rikker T, Eke Z. Comprehensive study of retention influencing gas chromatographic parameters affecting linear retention indices. J Chromatogr A 2024; 1729:465052. [PMID: 38852268 DOI: 10.1016/j.chroma.2024.465052] [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: 02/13/2024] [Revised: 05/31/2024] [Accepted: 06/04/2024] [Indexed: 06/11/2024]
Abstract
Retention in gas chromatographic systems has a central role in the identification of compounds even if detectors providing spectral information are used. But linear retention indices (LRI) of a single compound originating from multiple sources tend to vary greatly, probably due to differences in the experimental settings of the determinations. The effect of gas chromatographic parameters on LRI has been investigated using 41 compounds - previously identified from food contact plastics - and n-alkanes (n-C7-n-C40) used as reference series. As the reproducibility of LRIs under the same conditions is generally very good, the smallest changes in the settings often caused statistically significant, though irrelevant changes in the LRI values. Therefore, a multicriterial scoring-ranking system has been worked out to highlight the LRI value differences. Our results highlight that column length, heating rate, and film thickness can all be the reasons of the varying published LRI values. We also demonstrated that for the reproduction of LRI data, the chemistry (and not simply the polarity) of the stationary phase is crucial.
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Affiliation(s)
- Csaba Kirchkeszner
- Hevesy György PhD School of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary; Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Noémi Petrovics
- Hevesy György PhD School of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary; Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Aliz Széles
- Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Yelena Koshman
- Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Bálint Sámuel Szabó
- Hevesy György PhD School of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary; Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Zoltán Nyiri
- Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Márton Novák
- Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary; Doctoral School of Environmental Sciences, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary
| | - Tamás Rikker
- Wessling International Research and Educational Center, Anonymus u. 6, H-1045 Budapest, Hungary
| | - Zsuzsanna Eke
- Joint Research and Training Laboratory on Separation Techniques, Institute of Chemistry, Eötvös Loránd University, Pázmány Péter stny. 1/A, H-1117 Budapest, Hungary; Wessling International Research and Educational Center, Anonymus u. 6, H-1045 Budapest, Hungary.
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2
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Gaida M, Stefanuto PH, Focant JF. Theoretical modeling and machine learning-based data processing workflows in comprehensive two-dimensional gas chromatography-A review. J Chromatogr A 2023; 1711:464467. [PMID: 37871505 DOI: 10.1016/j.chroma.2023.464467] [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: 06/24/2023] [Revised: 10/15/2023] [Accepted: 10/17/2023] [Indexed: 10/25/2023]
Abstract
In recent years, comprehensive two-dimensional gas chromatography (GC × GC) has been gradually gaining prominence as a preferred method for the analysis of complex samples due to its higher peak capacity and resolution power compared to conventional gas chromatography (GC). Nonetheless, to fully benefit from the capabilities of GC × GC, a holistic approach to method development and data processing is essential for a successful and informative analysis. Method development enables the fine-tuning of the chromatographic separation, resulting in high-quality data. While generating such data is pivotal, it does not necessarily guarantee that meaningful information will be extracted from it. To this end, the first part of this manuscript reviews the importance of theoretical modeling in achieving good optimization of the separation conditions, ultimately improving the quality of the chromatographic separation. Multiple theoretical modeling approaches are discussed, with a special focus on thermodynamic-based modeling. The second part of this review highlights the importance of establishing robust data processing workflows, with a special emphasis on the use of advanced data processing tools such as, Machine Learning (ML) algorithms. Three widely used ML algorithms are discussed: Random Forest (RF), Support Vector Machine (SVM), and Partial Least Square-Discriminate Analysis (PLS-DA), highlighting their role in discovery-based analysis.
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Affiliation(s)
- Meriem Gaida
- Organic and Biological Analytical Chemistry Group (OBiAChem), MolSys Research Unit, Liège University, Belgium
| | - Pierre-Hugues Stefanuto
- Organic and Biological Analytical Chemistry Group (OBiAChem), MolSys Research Unit, Liège University, Belgium
| | - Jean-François Focant
- Organic and Biological Analytical Chemistry Group (OBiAChem), MolSys Research Unit, Liège University, Belgium
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3
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Comprehensive analytical and structural characteristics of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA). Forensic Toxicol 2021. [DOI: 10.1007/s11419-021-00573-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Abstract
Purpose
The purpose of the study was to evaluate a complete analytical and structural characterization of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA), a novel synthetic cannabinoid being the analogue of 5F-ADB.
Methods
The compound was analyzed by gas chromatography–mass spectrometry (GC–MS), high-resolution liquid chromatography–mass spectrometry (LC–MS), X-ray diffraction and spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies. To derive MDMB-4en-PINACA molecular geometry and to assign infrared absorption bands, quantum calculations with the employment of density functional theory were also used.
Results
We present a wide range of chromatographic and spectroscopic data supported with theoretical calculations allowing to identify MDMB-4en-PINACA.
Conclusions
To our knowledge, this is the first report presenting a comprehensive analytical and structural characterization of MDMB-4en-PINACA obtained by 1D and 2D NMR, GC–MS, LC–MS(/MS), attenuated total reflection-FTIR spectroscopy, powder X-ray diffraction and quantum chemical calculations. The presented results not only broaden the knowledge about this psychoactive substance but also are useful for forensic and clinical purposes.
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Dybowski MP, Holowinski P, Typek R, Dawidowicz AL. Comprehensive analytical characteristics of N-(adamantan-1-yl)-1- (cyclohexylmethyl)-1H-indazole-3-carboxamide (ACHMINACA). Forensic Toxicol 2020. [DOI: 10.1007/s11419-020-00547-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Abstract
Purpose
The aim of this study was to clarify the most essential analytical features of N-(adamantan-1-yl)-1-(cyclohexylmethyl)-1H-indazole-3-carboxamide (one of the newest cannabimimetics called ACHMINACA), to make them useful for analytical identification of this compound.
Methods
The compound was analyzed by gas chromatography–mass spectrometry, high-resolution liquid chromatography–mass spectrometry, crystal X-ray diffraction and spectroscopic methods such as nuclear magnetic resonance, Raman, and infrared spectroscopies.
Results
Detailed and comprehensive analytical data have been acquired for ACHMINACA.
Conclusions
Although brief descriptions of the partial data of ACHMINACA have appeared recently, this article provides the most detailed and comprehensive analytical data of ACHMINACA to our knowledge. Our data will significantly broaden the knowledge about the compound structure extending the possibility of its orthogonal analysis. The gathered data are useful for forensic, toxicological, and clinical purposes.
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5
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Sani MSA, Bakar J, Rahman RA, Abas F. Effects of Coated Capillary Column, Derivatization, and Temperature Programming on the Identification of Carica papaya Seed Extract Composition Using GC/MS Analysis. JOURNAL OF ANALYSIS AND TESTING 2020. [DOI: 10.1007/s41664-020-00118-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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6
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Stevenson KA, Blumberg LM, Harynuk JJ. Thermodynamics-based retention maps to guide column choices for comprehensive multi-dimensional gas chromatography. Anal Chim Acta 2019; 1086:133-141. [DOI: 10.1016/j.aca.2019.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 10/26/2022]
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7
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Hernandez-Baez DM, Reid A, Chapoy A, Tohidi B. Determination of distribution factors for heavy n-alkanes (nC 12-nC 98) in high temperature gas chromatography. J Chromatogr A 2019; 1591:138-146. [PMID: 30686646 DOI: 10.1016/j.chroma.2019.01.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 12/03/2018] [Accepted: 01/11/2019] [Indexed: 11/30/2022]
Abstract
The ultimate purpose of this research work is to get an insight into the incomplete elution of heavy n-alkanes which along with thermal cracking, is one of the two main factors questioning the reliability of High Temperature Gas Chromatography (HTGC) analysis of heavy oils. For this purpose, knowledge of how the Distribution Factors vary with temperature is an essential requirement in the GC modelling. This study provides an extension of the data set of distribution factors for n-alkanes up to nC98H198 in a HT5 GC column over the temperature range 10 °C-430 °C, and introduces a method to determine the distribution coefficient of heavy n-alkanes by using two complimentary HTGC modes: i.) High-Efficiency mode, for efficient resolution with a long column operated at low flow rate with n-alkanes elution rate up to nC64, and ii.) true SimDist mode, with a short column operated at high flow rate for inefficient resolution with n-alkanes elution rate up to nC100. Furthermore, this study demonstrates the use of the in-house obtained distribution factors as the main input in the in-house GC model for the prediction of the retention times. Its validation has been carried out using distribution factors obtained at both constant flow rate and constant inlet pressure operating conditions, with an average relative error in the GC modelling at the same operating conditions of 4.4% for the former and 1.5% for the latter. This new extension of the data set of heavy n-alkanes distribution factors provides the basis for studying the partitioning and incomplete elution of heavy n-alkanes in HTGC analysis. Also, these new distribution factors can be used as input in GC modelling, to determine the optimum analytical conditions to improve the separation process and thus the HTGC practices.
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Affiliation(s)
- Diana M Hernandez-Baez
- Hydrates, Flow Assurance & Phase Equilibria Group, Institute of Petroleum Engineering, Heriot Watt University, Edinburgh, Scotland, EH14 4AS, UK.
| | - Alastair Reid
- Hydrates, Flow Assurance & Phase Equilibria Group, Institute of Petroleum Engineering, Heriot Watt University, Edinburgh, Scotland, EH14 4AS, UK
| | - Antonin Chapoy
- Hydrates, Flow Assurance & Phase Equilibria Group, Institute of Petroleum Engineering, Heriot Watt University, Edinburgh, Scotland, EH14 4AS, UK.
| | - Bahman Tohidi
- Hydrates, Flow Assurance & Phase Equilibria Group, Institute of Petroleum Engineering, Heriot Watt University, Edinburgh, Scotland, EH14 4AS, UK
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8
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Tkachev AV. Problems of the Qualitative and Quantitative Analysis of Plant Volatiles. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1068162018070142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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9
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Acton WJF, Jud W, Ghirardo A, Wohlfahrt G, Hewitt CN, Taylor JE, Hansel A. The effect of ozone fumigation on the biogenic volatile organic compounds (BVOCs) emitted from Brassica napus above- and below-ground. PLoS One 2018; 13:e0208825. [PMID: 30532234 PMCID: PMC6287848 DOI: 10.1371/journal.pone.0208825] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 11/23/2018] [Indexed: 11/18/2022] Open
Abstract
The emissions of BVOCs from oilseed rape (Brassica napus), both when the plant is exposed to clean air and when it is fumigated with ozone at environmentally-relevant mixing ratios (ca. 135 ppbv), were measured under controlled laboratory conditions. Emissions of BVOCs were recorded from combined leaf and root chambers using a recently developed Selective Reagent Ionisation-Time of Flight-Mass Spectrometer (SRI-ToF-MS) enabling BVOC detection with high time and mass resolution, together with the ability to identify certain molecular functionality. Emissions of BVOCs from below-ground were found to be dominated by sulfur compounds including methanethiol, dimethyl disulfide and dimethyl sulfide, and these emissions did not change following fumigation of the plant with ozone. Emissions from above-ground plant organs exposed to clean air were dominated by methanol, monoterpenes, 4-oxopentanal and methanethiol. Ozone fumigation of the plants caused a rapid decrease in monoterpene and sesquiterpene concentrations in the leaf chamber and increased concentrations of ca. 20 oxygenated species, almost doubling the total carbon lost by the plant leaves as volatiles. The drop in sesquiterpenes concentrations was attributed to ozonolysis occurring to a major extent on the leaf surface. The drop in monoterpene concentrations was attributed to gas phase reactions with OH radicals deriving from ozonolysis reactions. As plant-emitted terpenoids have been shown to play a role in plant-plant and plant-insect signalling, the rapid loss of these species in the air surrounding the plants during photochemical pollution episodes may have a significant impact on plant-plant and plant-insect communications.
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Affiliation(s)
- W. J. F. Acton
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - W. Jud
- Institute of Ion and Applied Physics, University of Innsbruck, Innsbruck, Austria
- Helmholtz Zentrum München, Institute of Biochemical Plant Pathology, Research Unit Environmental Simulation (EUS), Neuherberg, Germany
| | - A. Ghirardo
- Helmholtz Zentrum München, Institute of Biochemical Plant Pathology, Research Unit Environmental Simulation (EUS), Neuherberg, Germany
| | - G. Wohlfahrt
- Institute of Ecology, University of Innsbruck, Innsbruck, Austria
| | - C. N. Hewitt
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - J. E. Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - A. Hansel
- Institute of Ion and Applied Physics, University of Innsbruck, Innsbruck, Austria
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10
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Ahmed WM, Brinkman P, Weda H, Knobel HH, Xu Y, Nijsen TM, Goodacre R, Rattray N, Vink TJ, Santonico M, Pennazza G, Montuschi P, Sterk PJ, Fowler SJ. Methodological considerations for large-scale breath analysis studies: lessons from the U-BIOPRED severe asthma project. J Breath Res 2018; 13:016001. [PMID: 30272570 DOI: 10.1088/1752-7163/aae557] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Methods for breath sampling and analysis require robust quality assessment to minimise the risk of false discoveries. Planning large-scale multi-site breath metabolite profiling studies also requires careful consideration of systematic and random variation as a result of sampling and analysis techniques. In this study we use breath sample data from the recent U-BIOPRED cohort to evaluate and discuss some important methodological considerations such as batch variation and correction, variation between sites, storage and transportation, as well as inter-instrument analytical differences. Based on this we provide a summary of recommended best practices for new large scale multi-site studies.
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Affiliation(s)
- Waqar M Ahmed
- School of Biological Sciences, University of Manchester, United Kingdom
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11
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Hou S, Stevenson KAJM, Harynuk JJ. A simple, fast, and accurate thermodynamic-based approach for transfer and prediction of gas chromatography retention times between columns and instruments Part I: Estimation of reference column geometry and thermodynamic parameters. J Sep Sci 2018; 41:2544-2552. [DOI: 10.1002/jssc.201701343] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/15/2018] [Accepted: 03/19/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Siyuan Hou
- Department of Chemistry; University of Alberta; Edmonton AB Canada
| | | | - James J. Harynuk
- Department of Chemistry; University of Alberta; Edmonton AB Canada
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12
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Jespers S, Schlautmann S, Gardeniers H, De Malsche W, Lynen F, Desmet G. Chip-Based Multicapillary Column with Maximal Interconnectivity to Combine Maximum Efficiency and Maximum Loadability. Anal Chem 2017; 89:11605-11613. [DOI: 10.1021/acs.analchem.7b03036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sander Jespers
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, 1050 Brussels, Belgium
| | - Stefan Schlautmann
- Mesoscale
Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, 7522
NB Enschede, The Netherlands
| | - Han Gardeniers
- Mesoscale
Chemical Systems, MESA+ Institute for Nanotechnology, University of Twente, 7522
NB Enschede, The Netherlands
| | - Wim De Malsche
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, 1050 Brussels, Belgium
| | - Frederic Lynen
- Universiteit Gent, Separation Science Group, Krijgslaan 281, B-9000 Gent, Belgium
| | - Gert Desmet
- Vrije Universiteit Brussel, Department of Chemical
Engineering, Pleinlaan
2, 1050 Brussels, Belgium
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13
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Evaluation of sources of irreproducibility of retention indices under programmed temperature gas chromatography conditions. J Chromatogr A 2017; 1495:57-63. [DOI: 10.1016/j.chroma.2017.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/04/2017] [Accepted: 03/06/2017] [Indexed: 11/20/2022]
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14
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Blumberg LM. Distribution-centric 3-parameter thermodynamic models of partition gas chromatography. J Chromatogr A 2017; 1491:159-170. [DOI: 10.1016/j.chroma.2017.02.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 11/26/2022]
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15
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Wu L, Duan X, Liu C, Zhang G, Li QX. Phenomenon of dual- and single-retention behaviors of solutes and its validation by computational simulation in linear programmed temperature gas chromatography. J Sep Sci 2016; 39:2785-95. [PMID: 27241084 DOI: 10.1002/jssc.201600236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/16/2016] [Accepted: 05/21/2016] [Indexed: 11/07/2022]
Abstract
The current theory of programmed temperature gas chromatography considers that solutes are focused by the stationary phase at the column head completely and does not explicitly recognize the different effects of initial temperature (To ) and heating rate (rT ) on the retention time or temperature of a homologue series. In the present study, n-alkanes, 1-alkenes, 1-alkyl alcohols, alkyl benzenes, and fatty acid methyl esters standards were used as model chemicals and were separated on two nonpolar columns, one moderately polar column and one polar column. Effects of To and rT on the retention of nonstationary phase focusing solutes can be explicitly described with isothermal and cubic equation models, respectively. When the solutes were in the stationary phase focusing status, the single-retention behavior of solutes was observed. It is simple, dependent upon rT only and can be well described by the cubic equation model that was visualized through four sequential slope analyses. These observed dual- and single-retention behaviors of solutes were validated by various experimental data, physical properties, and computational simulation.
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Affiliation(s)
- Liejun Wu
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Xiaojuan Duan
- Qingdao Entry-Exit Inspection and Quarantine Bureau, Qingdao, China
| | - Chuanyu Liu
- Institute of Oceanography, Chinese Academy of Sciences, Qingdao, China
| | - Guangxiang Zhang
- Office of Biostatistics and Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI, USA
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16
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Claumann CA, Wüst Zibetti A, Bolzan A, Machado RA, Pinto LT. Robust estimation of thermodynamic parameters (ΔH, ΔS and ΔC) for prediction of retention time in gas chromatography – Part I (Theoretical). J Chromatogr A 2015; 1425:249-57. [DOI: 10.1016/j.chroma.2015.10.072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 10/22/2022]
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17
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Fast and accurate numerical method for predicting gas chromatography retention time. J Chromatogr A 2015; 1406:258-65. [DOI: 10.1016/j.chroma.2015.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 06/03/2015] [Accepted: 06/03/2015] [Indexed: 11/18/2022]
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18
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Jiang M, Kulsing C, Nolvachai Y, Marriott PJ. Two-Dimensional Retention Indices Improve Component Identification in Comprehensive Two-Dimensional Gas Chromatography of Saffron. Anal Chem 2015; 87:5753-61. [DOI: 10.1021/acs.analchem.5b00953] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ming Jiang
- School of Pharmacy, Tongji Medical College, Huazhong University of Science & Technology, No. 13 Hangkong Road, Wuhan, Hubei 430030, PR China
| | - Chadin Kulsing
- Australian
Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Yada Nolvachai
- Australian
Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
| | - Philip J. Marriott
- Australian
Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800, Australia
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19
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Retention Indices for Identification of Aroma Compounds by GC: Development and Application of a Retention Index Database. Chromatographia 2014. [DOI: 10.1007/s10337-014-2801-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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20
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Antle PM, Zeigler CD, Livitz DG, Robbat A. Two-dimensional gas chromatography/mass spectrometry, physical property modeling and automated production of component maps to assess the weathering of pollutants. J Chromatogr A 2014; 1364:223-33. [DOI: 10.1016/j.chroma.2014.08.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/07/2014] [Accepted: 08/10/2014] [Indexed: 10/24/2022]
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21
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Nabi D, Gros J, Dimitriou-Christidis P, Arey JS. Mapping environmental partitioning properties of nonpolar complex mixtures by use of GC × GC. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:6814-6826. [PMID: 24901063 DOI: 10.1021/es501674p] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Comprehensive two-dimensional gas chromatography (GC × GC) is effective for separating and quantifying nonpolar organic chemicals in complex mixtures. Here we present a model to estimate 11 environmental partitioning properties for nonpolar analytes based on GC × GC chromatogram retention time information. The considered partitioning properties span several phases including pure liquid, air, water, octanol, hexadecane, particle natural organic matter, dissolved organic matter, and organism lipids. The model training set and test sets are based on a literature compilation of 648 individual experimental partitioning property data. For a test set of 50 nonpolar environmental contaminants, predicted partition coefficients exhibit root-mean-squared errors ranging from 0.19 to 0.48 log unit, outperforming Abraham-type solvation models for the same chemical set. The approach is applicable to nonpolar organic chemicals containing C, H, F, Cl, Br, and I, having boiling points ≤402 °C. The presented model is calibrated, easy to apply, and requires the user only to identify a small set of known analytes that adapt the model to the GC × GC instrument program. The analyst can thus map partitioning property estimates onto GC × GC chromatograms of complex mixtures. For example, analyzed nonpolar chemicals can be screened for long-range transport potential, aquatic bioaccumulation potential, arctic contamination potential, and other characteristic partitioning behaviors.
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Affiliation(s)
- Deedar Nabi
- Environmental Chemistry Modeling Laboratory, GR C2 544, Swiss Federal Institute of Technology at Lausanne (EPFL) , Station 2, CH-1015 Lausanne, Switzerland
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22
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Weber BM, Harynuk JJ. Application of thermodynamic-based retention time prediction to ionic liquid stationary phases. J Sep Sci 2014; 37:1460-6. [DOI: 10.1002/jssc.201301339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 02/21/2014] [Accepted: 03/19/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Brandon M. Weber
- Department of Chemistry; University of Alberta; Edmonton, Alberta Canada
| | - James J. Harynuk
- Department of Chemistry; University of Alberta; Edmonton, Alberta Canada
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McGinitie TM, Ebrahimi-Najafabadi H, Harynuk JJ. Rapid determination of thermodynamic parameters from one-dimensional programmed-temperature gas chromatography for use in retention time prediction in comprehensive multidimensional chromatography. J Chromatogr A 2014; 1325:204-12. [DOI: 10.1016/j.chroma.2013.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/02/2013] [Accepted: 12/03/2013] [Indexed: 10/25/2022]
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24
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Weber BM, Harynuk JJ. Gas chromatographic retention of alkyl phosphates on ionic liquid stationary phases. J Chromatogr A 2013; 1271:170-5. [DOI: 10.1016/j.chroma.2012.10.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 10/24/2012] [Accepted: 10/25/2012] [Indexed: 10/27/2022]
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25
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Seethapathy S, Górecki T. Applications of polydimethylsiloxane in analytical chemistry: A review. Anal Chim Acta 2012; 750:48-62. [PMID: 23062428 DOI: 10.1016/j.aca.2012.05.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/26/2012] [Accepted: 05/03/2012] [Indexed: 11/19/2022]
Affiliation(s)
- Suresh Seethapathy
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
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26
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Prediction of retention times in comprehensive two-dimensional gas chromatography using thermodynamic models. J Chromatogr A 2012; 1255:184-9. [DOI: 10.1016/j.chroma.2012.02.023] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 02/02/2012] [Accepted: 02/08/2012] [Indexed: 11/17/2022]
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27
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Reproducibility of Programmed-Temperature Retention Indices under Average Linear Velocity Carrier Gas Control of GC and GC–MS. Chromatographia 2011. [DOI: 10.1007/s10337-011-1956-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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Pérez-Vásquez A, Capella S, Linares E, Bye R, Angeles-López G, Mata R. Antimicrobial activity and chemical composition of the essential oil of Hofmeisteria schaffneri. ACTA ACUST UNITED AC 2011; 63:579-86. [PMID: 21401611 DOI: 10.1111/j.2042-7158.2010.01243.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The aims of this study were to establish the antimicrobial potential of Hofmeisteria schaffneri essential oil and its chemical composition. METHODS The essential oils of Hofmeisteria schaffneri harvested at flowering (batches I and IV) and non-flowering (batches II and III) seasons were prepared by hydrodistillation and analysed by GC and GC-MS. The aqueous and organic (CH(2) Cl(2) -MeOH 1 : 1) extracts were prepared by using infusion and maceration techniques, respectively. The in-vitro antimicrobial activity of the preparations and compounds against Candida albicans and some bacteria (Gram-negative and Gram-positive) was assessed using the broth dilution method in 96-microplate wells. KEY FINDINGS Forty-four compounds, representing ∼90% of the total constituents, were identified in the essential oil of Hofmeisteria schaffneri collected in flowering (batches I and IV) and non-flowering (batches II and III) seasons. In all cases, several thymol analogues were the major components of the oils (∼65%); some small differences in the relative proportions of these constituents were observed. The infusion exhibited an antibacterial activity against Staphylococcus aureus and Bacillus subtilis, with a MIC value of 64 µg/ml in each case. The essential oil batches were active against Staphylococcus aureus, with MIC ranging from 48 to 192 µg/ml. They were, however, inactive against Gram-negative bacteria, including Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi (MIC > 1024 µg/ml). On the other hand, the infusion of the plant as well as the oil from batch I displayed anti-Candida albicans activity, with MIC of 128 and 192 µg/ml, respectively. Finally, the organic extract did not displayed significant activity against the tested microorganisms (MIC ≥ 1024 µg/ml). Some of the compounds isolated from the plant were also tested. Compounds 8 and 38, which were present in the essential oils, displayed the best antibacterial effect against Gram-positive bacteria (MIC ranging between 32 and 64 µg/ml). Compounds 6 (present in the infusion) and 10 (present in all preparations) showed higher activity against the yeast (MIC = 128 µg/ml) than the remaining compounds, with MIC values ranging from 256 to 512 µg/ml. CONCLUSIONS The composition and antimicrobial activity of the oils changed slightly from flowering to non-flowering seasons. The results of the present investigation provide in-vitro scientific support for the use of the plant against skin infections in Mexican folk medicine.
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Affiliation(s)
- Araceli Pérez-Vásquez
- Departamento de Farmacia, Facultad de Química Instituto de Biología, Universidad Nacional Autónoma de México, México, México
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29
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Supercritical fluid extracts from the Brazilian cherry (Eugenia uniflora L.): Relationship between the extracted compounds and the characteristic flavour intensity of the fruit. Food Chem 2011. [DOI: 10.1016/j.foodchem.2010.05.109] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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30
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Seethapathy S, Górecki T. Polydimethylsiloxane-based permeation passive air sampler. Part I: Calibration constants and their relation to retention indices of the analytes. J Chromatogr A 2011; 1218:143-55. [DOI: 10.1016/j.chroma.2010.11.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 10/28/2010] [Accepted: 11/01/2010] [Indexed: 11/26/2022]
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31
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Inoue M, Saito Y, Ueta I, Miura T, Ohkita H, Fujimura K, Jinno K. Rapid temperature-programmed separation and retention prediction on a novel packed-capillary column in gas chromatography. ANAL SCI 2010; 26:687-91. [PMID: 20543501 DOI: 10.2116/analsci.26.687] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Novel packed-capillary columns for gas chromatography were developed with a thin-wall stainless-steel capillary of 1.0 mm i.d.; and rapid temperature-programmed separations have been carried out after a basic evaluation concerning the compatibility of these columns to the temperature program. With a numerical integration method, the retention of several test analytes during temperature-programmed elution was successfully estimated. In order to confirm the suitability of the packed-capillary columns to relatively fast temperature programming up to 40 degrees C/min, theoretically predicted retention data were compared with that actually measured. The results suggested a good separation performance of the newly developed packed-capillary columns as a particle-packed column conventionally used. Also, the compatibility to a rapid temperature-programmed operation was quite satisfactory for almost all of the separations currently done in typical analytical laboratories.
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Affiliation(s)
- Mitsuru Inoue
- Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi 441-8580, Japan
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32
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Peng C. Prediction of retention indices. VI: Isothermal and temperature-programmed retention indices, methylene value, functionality constant, electronic and steric effects. J Chromatogr A 2010; 1217:3683-94. [DOI: 10.1016/j.chroma.2010.02.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 01/29/2010] [Accepted: 02/01/2010] [Indexed: 11/27/2022]
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33
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Fatemi MH, Baher E, Ghorbanzade'h M. Predictions of chromatographic retention indices of alkylphenols with support vector machines and multiple linear regression. J Sep Sci 2009; 32:4133-42. [DOI: 10.1002/jssc.200900373] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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34
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Castello G, Moretti P, Vezzani S. Retention models for programmed gas chromatography. J Chromatogr A 2009; 1216:1607-23. [DOI: 10.1016/j.chroma.2008.11.049] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 11/17/2008] [Accepted: 11/19/2008] [Indexed: 11/29/2022]
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35
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Poole CF, Poole SK. Foundations of retention in partition chromatography. J Chromatogr A 2009; 1216:1530-50. [PMID: 19013576 DOI: 10.1016/j.chroma.2008.10.092] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 10/22/2008] [Accepted: 10/28/2008] [Indexed: 10/21/2022]
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36
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Shackleton CHL, Hughes BA, Lavery GG, Walker EA, Stewart PM. The corticosteroid metabolic profile of the mouse. Steroids 2008; 73:1066-76. [PMID: 18502460 DOI: 10.1016/j.steroids.2008.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 04/03/2008] [Accepted: 04/04/2008] [Indexed: 11/21/2022]
Abstract
Data are presented on the urinary corticosteroid metabolic profile of the mouse strain 129/svJ. Through the use of GC/MS we have characterized, or tentatively identified corticosterone (Kendall's compound B) metabolites of both the 11beta-hydroxy and 11-carbonyl (compound A) series in urine. Full mass spectra of the methyloxime-trimethylether derivatives of 15 metabolites are included in the paper as an aid to other researchers in the field. Metabolites ranged in polarity from tetrahydrocorticosterone (THB) to dihydroxy-corticosterone with dominance of highly polar steroids. We found that prior to excretion corticosterone can undergo oxidation at position 11beta, reduction at position 20 and A-ring reduction. Metabolites retaining the 3-oxo-4-ene structure can be hydroxylated at position 6beta- as well as at an unidentified position, probably 16alpha-. Saturated steroids can be hydroxylated at positions 1beta-, 6alpha-, 15alpha- and 16alpha. A pair of hydroxy-20-dihydro-corticosterone metabolites (OH-DHB) were the most important excretory products accounting for about 40% of the total. One metabolite of this type was identified as 6beta-hydroxy-DHB; the other, of similar quantitative importance was probably 16alpha-hydroxy-DHB. The ratio of metabolites of corticosterone (B) to those of 11-dehydro-corticosterone (A) was greater than 9:1, considerably higher than that for the equivalent "human" ratio of 1:1 for cortisol to cortisone metabolites. Results from this study allowed the evaluation of 11beta-hydroxysteroid dehydrogenase (11beta-HSD) activity in mice with deleted glucose-6-phosphate transporter (G6PT). These mice had attenuated back-conversion of A to B resulting in an increased ratio of A-metabolites to B-metabolites [Walker EA, Ahmed A, Lavery GG, Tomlinson JW, Kim SY, Cooper MS, Stewart PM, 11beta-Hydroxysteroid dehydrogenase type 1 regulation by intracellular glucose-6-phosphate, provides evidence for a novel link between glucose metabolism and HPA axis function. J Biol Chem 2007;282:27030-6]. We believe this study is currently the most comprehensive on the urinary steroid metabolic profile of the mouse. Quantitatively less steroid is excreted in urine than in feces by this species but urine analysis is more straightforward and the hepatic metabolites are less subject to microbial degradation than if feces was analyzed.
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Affiliation(s)
- C H L Shackleton
- Institute of Biomedical Research, Division of Medical Sciences, University of Birmingham, Birmingham B15 2TT, UK.
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37
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Santiuste JM, Tarján G, Ullrich E, Takács JM. Contribution to linearly programmed temperature gas chromatography. J Chromatogr A 2008; 1181:103-15. [DOI: 10.1016/j.chroma.2007.12.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 12/12/2007] [Accepted: 12/12/2007] [Indexed: 11/30/2022]
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38
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KANEKO T, AMASAKI I, NAKADA M, GAO Z. Evaluation of Retention Time for Temperature-programmed Gas Chromatography by Use of a Closed-form Integral. ANAL SCI 2008; 24:419-21. [DOI: 10.2116/analsci.24.419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
| | - Iwao AMASAKI
- Department of Electrical Engineering, Chiba Institute of Technology
| | - Masahiro NAKADA
- Department of Chemistry, Education Center, Chiba Institute of Technology
| | - Zhiming GAO
- Department of Chemistry, School of Sciences, Beijing Institute of Technology
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39
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Meshkatalsadat MH, Mirzaei HH. Chemical compositions of the essential oils of stems, leaves and flowers of Prangos acaulis (Dc) Bornm. Pak J Biol Sci 2007; 10:2775-2777. [PMID: 19070103 DOI: 10.3923/pjbs.2007.2775.2777] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Chemical composition of the essential oils obtained of stems, leaves and flowers of the Prangos acaulis, at full flowering stage were isolated by hydrodistilation method and investigated by GC/MS. A total of 11 compounds constituting 100% of stems oil, eighteen compounds constituting 99.74% of leaves oil and 22 compounds constituting 98.18% of flowers oil have been identified and quantified. The major components of stems oil were 3-ethylidene-2-methyl-1-hexen-4-yne (56.8%) and alpha-pinene (34.2%). The major components of leaves oil were a-pinene (39.54%), 3-ethylidene-2-methyl-1-hexen-4-yne (37.94%) and alpha-terpinene (10.9%) and the major components of flowers oil were alpha-pinene (25.04%), 3-ethylidene-2-methyl-1-hexen-4-yne (23.51%), alpha-terpinene (17.26%) and limonene (13.64%).
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40
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Massold E. Perdeuterated n-alkanes for improved data processing in thermal desorption gas chromatography/mass spectrometry. J Chromatogr A 2007; 1154:342-52. [PMID: 17452039 DOI: 10.1016/j.chroma.2007.03.078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 03/19/2007] [Accepted: 03/23/2007] [Indexed: 10/23/2022]
Abstract
The identification of organic compounds by GC/MS is useful in various areas such as fuel, indoor and outdoor air and flavour and fragrance applications. Multi-compound mixtures often contain isomeric compounds which have similar mass spectra and sometimes cannot be unambiguously identified by library search alone. Retention indices can help with confirmation of identification if they are reproducible. Using perdeuterated n-alkanes as a reference series for calculation of retention indices in GC/MS has a clear benefit because of the distinctive ion trace of m/z 34. Thermal desorption is useful for analysis of volatile organic compounds (VOCs) in air after sampling on appropriate sorbent cartridges. Comparison of indices between three systems, consisting of a thermal desorption unit, a gas chromatograph and a mass spectrometer, showed good agreement for compounds with well-defined peaks, whereas retention times varied.
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41
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Bianchi F, Careri M, Mangia A, Musci M. Retention indices in the analysis of food aroma volatile compounds in temperature-programmed gas chromatography: Database creation and evaluation of precision and robustness. J Sep Sci 2007; 30:563-72. [PMID: 17444225 DOI: 10.1002/jssc.200600393] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A retention index (RI) database containing 250 volatile compounds was created on a polar stationary phase column and validated for food aroma characterisation. Precision of the retention indices (RIs) was assessed by performing replicated injections of a representative number of volatiles under the same experimental conditions: differences lower than 1 U were observed for all the compounds. Robustness was evaluated by carrying out injections of the same set of volatile compounds under different experimental conditions, i.e. program temperature, column batches and instrumentation. Excellent results were obtained with a maximum difference in the RI values of 10 U. The capabilities of the created database for food aroma characterisation were finally evaluated by analysing the volatile fractions of different food matrices such as dry sausages, cheese and bread. A great number of volatile compounds were identified in the analysed samples on the basis of their RI, thus proving the usefulness of the RI collections in the field of food analysis.
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Affiliation(s)
- Federica Bianchi
- Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Università degli Studi di Parma, Parma, Italy
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42
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Zhao CX, Zhang T, Liang YZ, Yuan DL, Zeng YX, Xu QS. Conversion of programmed-temperature retention indices from one set of conditions to another. J Chromatogr A 2007; 1144:245-54. [PMID: 17266971 DOI: 10.1016/j.chroma.2007.01.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2006] [Revised: 01/09/2007] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
In order to make programmed-temperature retention index (PTRI) data be shared by other chromatographers and laboratories, conversion of PTRI from one set of experimental conditions to another is investigated in detail in this work. It was found that the differences between the PTRIs at different heating rates are structurally dependent, especially the number of ring in molecules. Thus, with the help of molecule constitutional descriptors, equations of PTRI conversion to certain initial temperature, heating rate, and stationary phase were obtained with high correlation coefficients and low standard deviations. Calculation errors of PTRI conversion between different heating rates and between different initial temperatures were from 1.1 to 2.9 retention index units (i.u.), which is in the same order with experiment errors. It is well known that reproducibility of PTRI on a polar column is not as good as that on an apolar column because of the apolarity of the n-alkane homologues. Thus, topological descriptors were used for PTRI conversion between two columns with different polar stationary phases, giving better results than those obtained by constitutional descriptors. This shows that topological descriptors could provide more molecular structural information than constitutional descriptors. However, as constitutional descriptor has the advantages of clear physical meaning and very simple calculation, it is our first selection when the PTRI calculation accuracy is satisfied. The method developed is simple in calculation, easy to be performed with high accuracy.
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Affiliation(s)
- Chen-Xi Zhao
- Department of Biological Engineering and Environmental Science, Changsha University, Changsha 410003, China.
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43
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González FR. Theoretical aspects of retention in overloaded columns. J Chromatogr A 2006; 1127:262-72. [PMID: 16815426 DOI: 10.1016/j.chroma.2006.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Revised: 05/29/2006] [Accepted: 06/06/2006] [Indexed: 10/24/2022]
Abstract
Issues regarding the concentration dependent solute distributions in overloaded chromatographic columns are discussed. Geometric simplicity of wall-coated capillary columns is taken as a reference and the discussion is developed using the example of the absorption isotherm of a solute having more affinity for itself than for the stationary phase. A retention function is deduced solving the equation of motion for the peak maximum, making some approximations. By means of this expression, the applicability of capillary gas chromatography (GC) as a technique for obtaining information on the sorption isotherm is analyzed.
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Affiliation(s)
- Francisco Rex González
- Química Analítica, Fac. Ciencias Exactas, Universidad Nacional de La Plata, 47 y 115, 1900 La Plata, Argentina.
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44
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Mjøs SA, Meier S, Boitsov S. Alkylphenol retention indices. J Chromatogr A 2006; 1123:98-105. [PMID: 16704870 DOI: 10.1016/j.chroma.2006.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 04/28/2006] [Accepted: 05/01/2006] [Indexed: 11/29/2022]
Abstract
A novel type of retention indices for alkylphenols and related compounds are proposed. The alkylphenol retention indices (APRI) use para-substituted n-alkylphenols as reference series. APRI for para-n-alkylphenols are per definition equal to the number of carbon atoms in the alkyl substituent; the value for phenol is zero. Application of the APRI system with different types of derivatisation of the phenolic hydroxy group showed that the derivatisation has limited influence on these indices. Especially para-substituted alkylphenols gave APRI values that could be transferred with high accuracy from one type of derivative to another. By comparing results obtained with different gradients in temperature-programmed GC, it was also shown that APRI is less affected by chromatographic conditions than retention indices based on n-alkanes.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Bergen, Norway
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45
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Mjøs SA. Prediction of equivalent chain lengths from two-dimensional fatty acid retention indices. J Chromatogr A 2006; 1122:249-54. [PMID: 16701676 DOI: 10.1016/j.chroma.2006.04.067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 04/20/2006] [Accepted: 04/25/2006] [Indexed: 10/24/2022]
Abstract
A recently introduced two-dimensional fatty acid retention index system (2D-FARI) was used as basis for prediction of equivalent chain lengths (ECL) of fatty acid methyl esters (FAME) on a BPX-70 stationary phase. Models for the relationship between 2D-FARI data and ECL values of a calibration sample with 30 common fatty acids were established by a simple multivariate regression. The models were thereafter applied on 2D-FARI data for other FAMEs and used to predict the ECLs for these compounds. The 2D-FARI values for the fatty acids in the calibration sample are given by definition. Thus, the only information necessary to calculate the ECL value for a compound run under identical conditions as the calibration sample is the 2D-FARI values for the compound, which can be acquired from literature data. The method was validated with test sets analysed with different temperature and flow programs. ECLs of various marine FAME and trans isomers of Eicosapentaenoic and Docosahexaenoic acid were predicted with root mean squared error of prediction from 0.002 to 0.012 ECL units.
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Affiliation(s)
- Svein A Mjøs
- Norwegian Institute of Fisheries and Aquaculture Research, Department SFF, Kjerreidviken 16, N-5141 Fyllingsdalen, Bergen, Norway.
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46
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Zabiegała B, Partyka M, Górecki T, Namieśnik J. Application of the chromatographic retention index system for the estimation of the calibration constants of permeation passive samplers with polydimethylsiloxane membranes. J Chromatogr A 2006; 1117:19-30. [PMID: 16600266 DOI: 10.1016/j.chroma.2006.03.069] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Revised: 03/14/2006] [Accepted: 03/16/2006] [Indexed: 10/24/2022]
Abstract
The paper presents the results of research on the calibration of permeation passive samplers equipped with polydimethylsiloxane (PDMS) membranes using the physico-chemical properties of the analytes. Strong correlations were found between the calibration constants of the samplers and the linear temperature-programmed retention indices of the analytes determined on columns coated with pure PDMS (r2 = 0.914). These correlations make it possible to estimate the calibration constants for unidentified analytes, which is impossible when using conventional procedures. This, in turn, enables the deployment of permeation passive samplers in the same way in which active samplers are deployed. The reproducibility of the calibration constants determined in different laboratories and retention indices determined using different chromatographic systems was very good, indicating that the calibration constants estimated using this approach should be reproducible as well. The approach proposed should lead to more widespread use of permeation passive samplers.
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Affiliation(s)
- Bozena Zabiegała
- Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology, 11/12 Narutowicza Str., 80-952 Gdańsk, Poland
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47
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Arey JS, Nelson RK, Xu L, Reddy CM. Using Comprehensive Two-Dimensional Gas Chromatography Retention Indices To Estimate Environmental Partitioning Properties for a Complete Set of Diesel Fuel Hydrocarbons. Anal Chem 2005; 77:7172-82. [PMID: 16285663 DOI: 10.1021/ac051051n] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Comprehensive two-dimensional gas chromatography (GCxGC) provides nearly complete composition data for some complex mixtures such as petroleum hydrocarbons. However, the potential wealth of physical property information contained in the corresponding two-dimensional chromatograms is largely untapped. We developed a simple but robust method to estimate GCxGC retention indices for diesel-range hydrocarbons. By exploiting n-alkanes as reference solutes in both dimensions, calculated retention indices were insensitive to uncertainty in the enthalpy of gas-stationary-phase transfer for a suite of representative diesel components. We used the resulting two-dimensional retention indices to estimate the liquid vapor pressures, aqueous solubilities, air-water partition coefficients, octanol-water partition coefficients, and vaporization enthalpies of a nearly complete set of diesel fuel hydrocarbons. Partitioning properties were typically estimated within a factor of 2; this is not as accurate as some previous estimation or measurement methods. However, these relationships may allow powerful and incisive analysis of phase-transfer processes affecting petroleum hydrocarbon mixtures in the environment. For example, GCxGC retention data might be used to quantitatively deconvolve the effects of water washing and evaporation on environmentally released diesel fuels.
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Affiliation(s)
- J Samuel Arey
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Massachusetts 02543, USA.
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48
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Chemical Compositions of the Essential Oils of Stems, Leaves, and Roots of Prangos latiloba. Chem Nat Compd 2005. [DOI: 10.1007/s10600-005-0201-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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49
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Sauvain JJ, Duc TV. Approaches to identifying and quantifying polycyclic aromatic hydrocarbons of molecular weight 302 in diesel particulates. J Sep Sci 2004; 27:78-88. [PMID: 15335062 DOI: 10.1002/jssc.200301620] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Among the PAH class of compounds, high molecular weight PAH are now considered as relevant cancer inducers, but not all of them have the same biological activity. However, their analysis is difficult, mainly due to the presence of numerous isomers and due to their low volatility. Retention indices (Ri) for 13 dibenzopyrenes and homologues were determined by high-resolution capillary gas chromatography (GC) with four different stationary phases: a 5% phenyl-substituted methylpolysiloxane column (DB-5 ms), a 35% phenyl-substituted methylpolysiloxane column (BPX-35), a 50% phenyl-substituted methylpolysiloxane column (BPX-50), and a 35% trifluoropropylmethyl polysiloxane stationary phase (Rtx-200). Correlations for retention on each phase were investigated by using 8 independent molecular descriptors. Ri has been shown to be linearly correlated to PAH volume, polarisability alpha, Hückel-pi energy on the four examined columns. Ionisation potential Ip is a fourth variable which improves the regression model for DB-5ms, BPX-35, and BPX-50 column. Correlation coefficients ranging from r2 = 0.935 to r2 = 0.952 are then observed. Application of these indices to the identification and quantification of PAH with MW 302 in certified diesel particulate matter SRM 1650a is presented and discussed.
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Affiliation(s)
- Jean-Jacques Sauvain
- Institut Universitaire Romand de Sante au Travail, Rue du Bugnon 19, CH-1005 Lausanne.
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