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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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Geer LY, Stein SE, Mallard WG, Slotta DJ. AIRI: Predicting Retention Indices and Their Uncertainties Using Artificial Intelligence. J Chem Inf Model 2024; 64:690-696. [PMID: 38230885 DOI: 10.1021/acs.jcim.3c01758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
The Kováts retention index (RI) is a quantity measured using gas chromatography and is commonly used in the identification of chemical structures. Creating libraries of observed RI values is a laborious task, so we explore the use of a deep neural network for predicting RI values from structure for standard semipolar columns. This network generated predictions with a mean absolute error of 15.1 and, in a quantification of the tail of the error distribution, a 95th percentile absolute error of 46.5. Because of the Artificial Intelligence Retention Indices (AIRI) network's accuracy, it was used to predict RI values for the NIST EI-MS spectral libraries. These RI values are used to improve chemical identification methods and the quality of the library. Estimating uncertainty is an important practical need when using prediction models. To quantify the uncertainty of our network for each individual prediction, we used the outputs of an ensemble of 8 networks to calculate a predicted standard deviation for each RI value prediction. This predicted standard deviation was corrected to follow the error between the observed and predicted RI values. The Z scores using these predicted standard deviations had a standard deviation of 1.52 and a 95th percentile absolute Z score corresponding to a mean RI value of 42.6.
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Affiliation(s)
- Lewis Y Geer
- National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, United States
| | - Stephen E Stein
- National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, United States
| | - William Gary Mallard
- National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, United States
| | - Douglas J Slotta
- National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, Maryland 20899, United States
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3
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Klee S, Bräkling S, Vetter M, Bieber S, Letzel T. Nontargeted Screening for the Verification of Allergenic Ingredients and Perfume Authenticity by GC-ecTOF-MS. LCGC NORTH AMERICA 2022. [DOI: 10.56530/lcgc.na.iz1276q6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Fraudulent products are ubiquitous in all markets. Besides the financial aspect, a major issue regarding products adulteration for society and the environment is the missing regulation and control of these goods. Therefore, harmful and toxic compounds in fraudulent products may become a risk for human health and the environment. Even small amounts of toxic substances can still have damaging effects. Thus, a sensitive and reliable identification of compounds is needed. Novel technologies are necessary to use identifying and preventing fraud and related risks. Goods from the food, flavor, and fragrance markets often contain volatile organic compounds (VOCs), which include most allergenic fragrances. For the detection and identification of these substances, gas chromatographic separation hyphenated with high resolution mass spectrometry (GC–HRMS) is an ideal instrumental technique. GC–simultaneous electron and chemical ionization (ec) time-of-flight (TOF)-MS generates various types of information via simultaneous ec–HRMS. Advantages are given for target, known unknown, and unknown unknown data analysis by generating various types of ions within one single experimental GC–MS run. In this study, the experimental nontargeted screening approach and corresponding data analysis workflows—simultaneously using molecular ion information and structural information—are presented for the molecular identification and authenticity verification process from a brand perfume using GC–ecTOF-MS.
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Affiliation(s)
| | | | | | - Stefan Bieber
- Analytisches Forschungsinstitut für Non-Target Screening GmbH (AFIN-TS)
| | - Thomas Letzel
- Analytisches Forschungsinstitut für Non-Target Screening GmbH (AFIN-TS)
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Zacca JJ, Giudice GH, Souza MP, Caldas LNB, Vieira ML, Machado AHL. Development and validation of analytical method for identification of new psychoactive substances using linear retention indexes and gas chromatography-mass spectrometry. J Chromatogr A 2020; 1636:461783. [PMID: 33340744 DOI: 10.1016/j.chroma.2020.461783] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 11/16/2020] [Accepted: 12/01/2020] [Indexed: 10/22/2022]
Abstract
New Psychoactive Substances (NPS) are quickly developing to evade legislation, posing unprecedented challenges to public health and law enforcement authorities around the world. The aim of this work was to develop and validate a simple and reliable non-target gas chromatography/mass spectrometry (GC/MS) analytical method based on linear retention indexes for the expeditious identification of NPS without the need of analytical standards. The method was optimized and validated for 22 different drugs covering ten categories: phenethylamines (amphetamine, MDMA, methamphetamine, 25CNBOMe, 2-FA, 5-MAPB), "classic" drugs (cocaine, ephedrine, THC, heroine), synthetic cannabinoids (JWH-081, AM-2201, JWH-210, MAM-2201), piperazines (o-CPP, p-CPP), tryptamines (5-MeO-MiPT), synthetic cathinones (N-ethylpentylone), synthetic opioids (U-47700), aminoindanes (5-IAI), plant-based substances (Salvinorin-A) and "other" (methiopropamine). Three figures of merit (Selectivity, Precision and Robustness) were evaluated with retention index confidence intervals ranging from 0.5 to 20.6 i.u. and relative standard deviations in the range of 0.003% to 0.027% (repeatability) and 0.02% to 0.29% (intermediate precision). A general equation for estimating linear retention index variation as a function of retention time tolerance has been derived. This result in combination with a 2III6-3 fractional factorial design allowed to conclude column polarity to be only statistically relevant factor as compared to gas flow, split ratio, injection temperature, temperature program offset and column brand.
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Affiliation(s)
- Jorge J Zacca
- National Institute of Criminalistics - Brazilian Federal Police (INC/PF) - SPO Lote 7 - Setores Complementares - Brasília/DF - 70.610-902, Brazil.
| | - Gabriella H Giudice
- Brazilian Health Regulatory Agency (ANVISA) SIA - Trecho 5 - Área Especial 57 - Bloco D - 71.205.050 - Brasília/DF, Brazil; Institute of Chemistry, University of Brasília (IQ/UnB), P.O. Box 4478, 70904-970 Brasília, Distrito Federal, Brazil
| | - Mônica P Souza
- National Institute of Criminalistics - Brazilian Federal Police (INC/PF) - SPO Lote 7 - Setores Complementares - Brasília/DF - 70.610-902, Brazil.
| | - Luíza N B Caldas
- National Institute of Criminalistics - Brazilian Federal Police (INC/PF) - SPO Lote 7 - Setores Complementares - Brasília/DF - 70.610-902, Brazil.
| | - Maurício L Vieira
- National Institute of Criminalistics - Brazilian Federal Police (INC/PF) - SPO Lote 7 - Setores Complementares - Brasília/DF - 70.610-902, Brazil.
| | - Angelo H L Machado
- Institute of Chemistry, University of Brasília (IQ/UnB), P.O. Box 4478, 70904-970 Brasília, Distrito Federal, Brazil
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Kupriyanova OV, Shevyrin VA, Shafran YM, Lebedev AT, Milyukov VA, Rusinov VL. Synthesis and determination of analytical characteristics and differentiation of positional isomers in the series of
N
‐(2‐methoxybenzyl)‐2‐(dimethoxyphenyl)ethanamine using chromatography–mass spectrometry. Drug Test Anal 2020; 12:1154-1170. [DOI: 10.1002/dta.2859] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/29/2022]
Affiliation(s)
- Olga V. Kupriyanova
- A.E. Arbuzov Institute of Organic and Physical Chemistry FRC Russian Academy of Sciences, Kazan Scientific Center Kazan Russian Federation
- Kazan State Medical University Kazan Russian Federation
| | - Vadim A. Shevyrin
- Ural Federal University Institute of Chemistry and Technology Ekaterinburg Russian Federation
| | - Yuri M. Shafran
- Ural Federal University Institute of Chemistry and Technology Ekaterinburg Russian Federation
| | - Albert T. Lebedev
- Organic Chemistry Department Lomonosov Moscow State University Moscow Russian Federation
| | - Vasili A. Milyukov
- A.E. Arbuzov Institute of Organic and Physical Chemistry FRC Russian Academy of Sciences, Kazan Scientific Center Kazan Russian Federation
| | - Vladimir L. Rusinov
- Ural Federal University Institute of Chemistry and Technology Ekaterinburg Russian Federation
- Postovsky Institute of Organic Synthesis Ural Branch of the Russian Academy of Sciences Yekaterinburg Russian Federation
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6
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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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Škrbić BD, Cvejanov JD, Pavić-Suzuki LS. Contribution to the unified retention data of hydrocarbons on squalane. Chromatographia 2016. [DOI: 10.1007/bf02267698] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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8
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Santiuste JM, Quintanilla-López JE, Becerra R, Gutiérrez C, Lebrón-Aguilar R. Factors Influencing the Isothermal Retention Indices of 51 Solutes on 12 Stationary Phases of Different Polarity: Applicability of the Solvation Parameter Model. Chromatographia 2015. [DOI: 10.1007/s10337-015-2924-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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10
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Wu L, Chen M, Chen Y, Li QX. A new accurate quadratic equation model for isothermal gas chromatography and its comparison with the linear model. J Chromatogr A 2012; 1260:224-31. [PMID: 22989489 PMCID: PMC3715325 DOI: 10.1016/j.chroma.2012.08.071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 08/18/2012] [Accepted: 08/20/2012] [Indexed: 11/20/2022]
Abstract
The gas holdup time (tM) is a dominant parameter in gas chromatographic retention models. The difference equation (DE) model proposed by Wu et al. (J. Chromatogr. A 2012, http://dx.doi.org/10.1016/j.chroma.2012.07.077) excluded t(M). In the present paper, we propose that the relationship between the adjusted retention time t'RZ and carbon number z of n-alkanes follows a quadratic equation (QE) when an accurate tM is obtained. This QE model is the same as or better than the DE model for an accurate expression of the retention behavior of n-alkanes and model applications. The QE model covers a larger range of n-alkanes with better curve fittings than the linear model. The accuracy of the QE model was approximately 2-6 times better than the DE model and 18-540 times better than the LE model. Standard deviations of the QE model were approximately 2-3 times smaller than those of the DE model.
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Affiliation(s)
- Liejun Wu
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Maoxue Chen
- College of Information Science and Engineering, Shandong Agricultural University, Taian 271018, China
| | - Yongli Chen
- College of Natural and Computational Sciences, Hawaii Pacific University, 45-045 Kamehameha Highway, Kaneohe, HI 96744, USA
| | - Qing X. Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Wu L, Chen Y, Caccamise SA, Li QX. Difference equation model for isothermal gas chromatography expresses retention behavior of homologues of n-alkanes excluding the influence of holdup time. J Chromatogr A 2012; 1260:215-23. [PMID: 22939376 PMCID: PMC3587695 DOI: 10.1016/j.chroma.2012.07.077] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/25/2012] [Accepted: 07/26/2012] [Indexed: 12/01/2022]
Abstract
A difference equation (DE) model is developed using the methylene retention increment (Δtz) of n-alkanes to avoid the influence of gas holdup time (tM). The effects of the equation orders (1st-5th) on the accuracy of a curve fitting show that a linear equation (LE) is less satisfactory and it is not necessary to use a complicated cubic or higher order equation. The relationship between the logarithm of Δtz and the carbon number (z) of the n-alkanes under isothermal conditions closely follows the quadratic equation for C3-C30n-alkanes at column temperatures of 24-260 °C. The first and second order forward differences of the expression (Δlog Δtz and Δ2log Δtz, respectively) are linear and constant, respectively, which validates the DE model. This DE model lays a necessary foundation for further developing a retention model to accurately describe the relationship between the adjusted retention time and z of n-alkanes.
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Affiliation(s)
- Liejun Wu
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Yongli Chen
- College of Natural and Computational Sciences, Hawaii Pacific University, 45-045 Kamehameha Highway, Kaneohe, HI 96744, USA
| | - Sarah A.L. Caccamise
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Qing X. Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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12
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Behaviour of the isothermal retention indices of n-alkylbenzenes on stationary phases of different polarity. J Chromatogr A 2012; 1222:90-7. [DOI: 10.1016/j.chroma.2011.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 11/30/2011] [Accepted: 12/01/2011] [Indexed: 11/22/2022]
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13
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Characterization of the volatile fraction emitted by Pinus spp. by one- and two-dimensional chromatographic techniques with mass spectrometric detection. J Chromatogr A 2010; 1217:1845-55. [DOI: 10.1016/j.chroma.2010.01.045] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Revised: 01/12/2010] [Accepted: 01/14/2010] [Indexed: 11/22/2022]
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14
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Zellner BD, Bicchi C, Dugo P, Rubiolo P, Dugo G, Mondello L. Linear retention indices in gas chromatographic analysis: a review. FLAVOUR FRAG J 2008. [DOI: 10.1002/ffj.1887] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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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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16
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Lebrón-Aguilar R, Quintanilla-López JE, Tello AM, Santiuste JM. Isothermal retention indices on poly(3,3,3-trifluoropropylmethylsiloxane) stationary phases. J Chromatogr A 2007; 1160:276-88. [PMID: 17537449 DOI: 10.1016/j.chroma.2007.05.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Revised: 05/09/2007] [Accepted: 05/10/2007] [Indexed: 11/25/2022]
Abstract
Isothermal retention indices (I) of 56 solutes of varied chemical nature and polarity were determined by a well-proven accurate method on poly(3,3,3-trifluoropropylmethylsiloxanes) with trifluoropropyl group percentages between 0 and 50% within the 353-413 K temperature range. The column temperature effect on the retention index for a representative set of solutes was studied. The linear model and the recent expression I = a + bT(-1) + c ln T were discussed. The retention index dependence on the polymer polarity was also investigated. Principal component analysis and multiple linear regression (MLR) were applied to obtain retention models relating the I values to physicochemical and molecular properties of the solutes chromatographed. The best model of prediction of the retention in these fluorinated stationary phases was obtained by using the Abraham's descriptors.
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Affiliation(s)
- Rosa Lebrón-Aguilar
- Department of Structure and Molecular Dynamics, Institute of Physical Chemistry Rocasolano (CSIC), Serrano 119, 28006 Madrid, Spain
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Babushok VI, Linstrom PJ, Reed JJ, Zenkevich IG, Brown RL, Mallard WG, Stein SE. Development of a database of gas chromatographic retention properties of organic compounds. J Chromatogr A 2007; 1157:414-21. [PMID: 17543315 DOI: 10.1016/j.chroma.2007.05.044] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 05/01/2007] [Accepted: 05/03/2007] [Indexed: 11/21/2022]
Abstract
A comprehensive database of gas chromatographic retention properties of chemical compounds has been developed using multiple literature sources. The National Institute of Standards and Technology (NIST) database of retention data for non-polar and polar stationary phases currently contains 292,924 data records for 42,888 compounds. The database includes data for Kováts indices, linear indices, Lee indices, retention times and retention volumes. The first release of this database for non-polar stationary phases is available with NIST/US Environmental Protection Agency (EPA)/National Institutes of Health (NIH) Mass Spectral Database (June 2005) and through the internet (NIST Chemistry WebBook). The paper describes the database and the process by which it has been compiled. The format of data presentation and the quality control procedures are described. Data sources of gas chromatographic retention data are also discussed.
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Affiliation(s)
- V I Babushok
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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18
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Zhu XH, Wang W, Schramm KW, Niu W. Prediction of the Kováts Retention Indices of Thiols by Use of Quantum Chemical and Physicochemical Descriptors. Chromatographia 2007. [DOI: 10.1365/s10337-007-0237-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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19
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Stein SE, Babushok VI, Brown RL, Linstrom PJ. Estimation of Kováts retention indices using group contributions. J Chem Inf Model 2007; 47:975-80. [PMID: 17367127 DOI: 10.1021/ci600548y] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have constructed a group contribution method for estimating Kováts retention indices by using observed data from a set of diverse organic compounds. Our database contains observed retention indices for over 35,000 different molecules. These were measured on capillary or packed columns with polar and nonpolar (or slightly polar) stationary phases under isothermal or nonisothermal conditions. We neglected any dependence of index values on these factors by averaging observations. Using 84 groups, we determined two sets of increment values, one for nonpolar and the other for polar column data. For nonpolar column data, the median absolute prediction error was 46 (3.2%). For data on polar columns, the median absolute error was 65 (3.9%). While accuracy is insufficient for identification based solely on retention, it is suitable for the rejection of certain classes of false identifications made by gas chromatography/mass spectrometry.
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Affiliation(s)
- Stephen E Stein
- Physical and Chemical Properties Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899-8380, USA.
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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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21
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Sun L, Siepmann JI, Klotz WL, Schure MR. Retention in gas–liquid chromatography with a polyethylene oxide stationary phase: Molecular simulation and experiment. J Chromatogr A 2006; 1126:373-80. [PMID: 16814798 DOI: 10.1016/j.chroma.2006.05.084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 05/20/2006] [Accepted: 05/30/2006] [Indexed: 11/16/2022]
Abstract
Configurational-bias Monte Carlo simulations in the isobaric-isothermal Gibbs ensemble were carried out to investigate the partitioning of normal alkanes, primary and secondary alcohols, symmetric alkyl ethers and arenes between a helium vapor phase and a polyethylene oxide stationary phase (M(W)=382 g mol(-1)). The united-atom version of the transferable potentials for phase equilibria force field was used to model all solutes, polyethylene oxide and helium. The Gibbs free energies of transfer and Kovats retention indices of the solutes were calculated directly from the partition constants at two different temperatures, 353 and 393 K. Chromatographic experiments on a Carbowax 20M retentive phase were performed for the same set of solutes and temperatures ranging from 333 to 413 K. The predicted retention indices for alcohols, ethers and arenes are overestimated by about 120, 70 and 20 retention index units, respectively, pointing to an overestimation of the first-order electrostatic interactions in the model system. Molecular-level analysis shows that hydrogen-bonding and dipole-dipole interactions lead to orientational ordering for the alcohol and ether analytes, whereas the weaker dipole-quadrupole interactions for the arene solutes are not sufficient to induce orientational ordering. The retention indices of alcohols and ethers decrease with increasing temperature because of the large entropic cost of hydrogen-bonding and orientational ordering. In contrast, the retention indices for arenes increase with increasing temperature because the entropic cost of cavity formation is smaller for arenes than for comparable alkanes.
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Affiliation(s)
- Li Sun
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
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22
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Vezzani S, Moretti P, Castello G. Classification and comparison of capillary columns by determination of the solution enthalpy of polar and non polar probes. J Chromatogr A 2006; 1101:261-7. [PMID: 16289083 DOI: 10.1016/j.chroma.2005.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Revised: 09/30/2005] [Accepted: 10/05/2005] [Indexed: 10/25/2022]
Abstract
The behaviour and separation characteristics of capillary columns containing different stationary phases (bonded methyl- and methylphenylsiloxanes and polyglycols, and carbon layer and porous polymer) were classified and compared by measuring the values of the solution enthalpy DeltaHs of n-alkanes and 1-alcohols at various temperatures. The difference in DeltaHs values between straight-chain 1-alcohols and n-alkanes with the same number of carbon atom (DeltaDeltaHs) does not change with changing temperature when gas-liquid partition stationary phases are used, but depends on the column composition and polarity and therefore permits to evaluate the influence of polarity on the solute-solvent interaction. The trend of the DeltaDeltaHs values is correlated with that of the DeltaC parameter and with the McReynolds' polarity constants.
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Affiliation(s)
- S Vezzani
- University of Genova, Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31, I-16146 Genova, Italy
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23
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Preliminary study of the retention behavior for different compounds using cryogenic chromatography at different initial temperatures. Microchem J 2005. [DOI: 10.1016/j.microc.2005.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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24
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Sun L, Wick CD, Siepmann JI, Schure MR. Temperature Dependence of Hydrogen Bonding: An Investigation of the Retention of Primary and Secondary Alcohols in Gas−Liquid Chromatography. J Phys Chem B 2005; 109:15118-25. [PMID: 16852913 DOI: 10.1021/jp0512006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Configurational-bias Monte Carlo simulations in the Gibbs Ensemble were carried out to investigate the analyte partitioning of n-pentane, n-hexane, n-heptane, 1-propanol, and 2-propanol into a dioctyl ether retentive (stationary) phase used in gas-liquid chromatography. The united-atom version of the TraPPE (transferable potentials for phase equilibria) force field was used to model all analytes and the solvent. The analyte partition coefficients, Gibbs free energies of transfer, and Kovats retention indexes were calculated at four different temperatures ranging from 303.15 to 348.15 K. Although hydrogen bonding is a major contributor to the retention of the alcohol analytes over the entire temperature range, its importance for the separation factor between the primary and secondary alcohol decreases substantially with increasing temperature. The enthalpies and entropies for hydrogen bond formation were also estimated from the temperature dependence of the corresponding equilibrium constants. In agreement with experimental measurements, it is observed that the hydrogen bond involving 1-propanol is enthalpically favored, but entropically disfavored compared to 2-propanol.
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Affiliation(s)
- Li Sun
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, USA
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25
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Pérez-Parajón JM, Santiuste JM, Takács JM. Sensitivity of the methylbenzenes and chlorobenzenes retention index to column temperature, stationary phase polarity, and number and chemical nature of substituents. J Chromatogr A 2004; 1048:223-32. [PMID: 15481260 DOI: 10.1016/j.chroma.2004.07.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Retention indices of methylbenzenes and chlorobenzenes on two fused silica capillary columns, HP-5 (diphenylsiloxane 5% diphenyldimethylsiloxane) and ZB-WAX (polyethylene glycol), have been calculated at various isothermal temperatures and compared with literature data. The retention index temperature effect was studied for each solute, finding greater retention index the higher the column temperature. A comparison between the straight line fit and the fit to the recently proposed equation I = A + B/T +C ln T was carried out. The effect of the stationary phase polarity on the retention index was checked. In general, a greater retention index was found for the more polar stationary phase. The retention indices of the chlorobenzenes are greater than the retention indices of the methylbenzenes, irrespective of the stationary phase and the column temperature. In addition, the influence of the methyl/chlorine substitution on the benzene molecule was investigated at each temperature. The retention indices increased as the number of substituents (methyl/chlorine) increased. The retention index increments of methyl and chloro derivatives are also discussed, which permits to compare the effect of both, methyl or chlorine, chemical functions, for a fixed substituent number in the benzene molecule.
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Affiliation(s)
- Juan M Pérez-Parajón
- Department of Structure and Molecular Dynamics, Instituto de Química Física Rocasolano, CSIC, C Serrano 119, 28006-Madrid, Spain
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26
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Temperature dependence of the Kovats retention indices for alkyl 1, 3-diketones on a DB-5 capillary column. JOURNAL OF THE SERBIAN CHEMICAL SOCIETY 2004. [DOI: 10.2298/jsc0410759m] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A series of alkyl 1,3-diketones were used to study the temperature dependence of the Kovats retention indices in the temperature range 130?190 ?C (403?463 K). The temperature dependence is described by the empirical equation I = B B/T + ClnT. On the basis of this equation, the activation enthalpy, ?H?, and the chemical potential of the partitioning of one methylene group between the two phases of the chromatographic system, ??p(CH2), were calculated. Also the Kovats retention indices ? boiling point correlations (linear and reciprocal) for alkyl 1,3-diketones were studied and ??p(CH2) was calculated.
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27
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Miller KE, Bruno TJ. Isothermal Kováts retention indices of sulfur compounds on a poly(5% diphenyl-95% dimethylsiloxane) stationary phase. J Chromatogr A 2003; 1007:117-25. [PMID: 12924557 DOI: 10.1016/s0021-9673(03)00958-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Isothermal Kováts retention indices of 21 sulfur compounds relevant to the fuel gas and food industries are reported on a poly(5% diphenyl-95% dimethylsiloxane) capillary column stationary phase. Measurements were performed at four temperatures and the temperature dependence of the values modeled with Antoine-type equations. Indices were calculated using a non-linear technique, and the predicted values were found to agree with values obtained using traditional logarithmic predictions. We demonstrate that there is sufficient separation between retention indices to predict the identity of a compound by its retention index.
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Affiliation(s)
- Keith E Miller
- Chemical Science and Technology Laboratory, Physical and Chemical Properties Division, National Institute of Standards and Technology (NIST), 325 Broadway, Boulder, CO 80305, USA
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28
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Abstract
For the fast gas chromatographic identification of separated components the retention index is still one of the most often used tools, although mass spectrometry is available in almost all analytical laboratories. For the calculation of the retention indices it is not necessary to use n-alkanes or any other homologous series. If the analyte contains some compounds, not necessarily belonging to a homologous series, with well-known retention indices those compounds can be used as index references and the index of the other compounds can be calculated as is done using n-alkanes. The only difference is that instead of the carbon number of the n-alkanes, virtual carbon numbers of the reference compounds should be used. The method of calculation, and the effect of this method of calculation on the reproducibility are discussed in this paper, and analyses of some halogenated compounds and marjoram oil are used as experimental examples.
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Affiliation(s)
- János Harangi
- Agilent Technologies GmbH, European Field Support Center, Hewlett-Packard Strasse 8, D-76337 Waldbronn, Germany.
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29
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Görgényi M, Héberger K. Minimum in the temperature dependence of the Kováts retention indices of nitroalkanes and alkanenitriles on an apolar phase. J Chromatogr A 2003; 985:11-9. [PMID: 12580465 DOI: 10.1016/s0021-9673(02)01842-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Kováts retention indices (I) of 1-nitroalkanes and alkanenitriles were determined on polydimethylsiloxane and Innowax (polyethylene glycol) columns in a wide temperature range. The temperature dependence of the retention indices exhibits a definite minimum for the early members of the homologous series. The position of the minimum shifts to lower temperatures with increasing carbon atom number of the solute. The thermodynamic explanation of an extreme in the I vs. T function is the higher solvation heat capacities of nitroalkanes and alkanenitriles relative to those of the reference n-alkanes, owing to the deviation from the ideal state in the solution. A novel equation was derived which describes the minimum in the I vs. T function, too.
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Affiliation(s)
- Mikiós Görgényi
- Department of Physical Chemistry, University of Szeged, P.O. Box 105 H-6701 Szeged, Hungary.
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30
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Héberger K, Görgényi M, Kowalska T. Temperature dependence of Kováts indices in gas chromatography revisited. J Chromatogr A 2002; 973:135-42. [PMID: 12437171 DOI: 10.1016/s0021-9673(02)01198-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Temperature dependence of the Kováts retention index (I) was measured for some aliphatic ketones and aldehydes on a poly(dimethyl siloxane) (HP-1) stationary phase. An interesting minimum (non-linearity) was observed for the I versus isothermal column temperature (T) relationships. A novel empirical model is proposed: I=A+B/T+C ln T, where A, B and Care equation constants and B/C = T(min). A detailed statistical analysis clearly shows superiority of the extended model (i.e., of this containing the logarithm of the temperature (ln T) term) over the earlier established Antoine-type reciprocal equation. The minimum temperature (and the energy like quantity=RT(min), where R is the gas constant) changes in a systematic manner. The factors effecting the (RT(min)) term are as follows: (i) this term decreases with the increase of the molecular mass of the respective oxo compounds; (ii) ketones have higher absolute values of (RT(min) than aldehydes; (iii) branching of the carbon chain lowers the mentioned (RT(min)). This enthalpy term is unambiguously bound to the polarity of solutes.
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Affiliation(s)
- Károly Héberger
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest.
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31
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Wick CD, Siepman JI, Klotz WL, Schure MR. Temperature effects on the retention of n-alkanes and arenes in helium-squalane gas-liquid chromatography. Experiment and molecular simulation. J Chromatogr A 2002; 954:181-90. [PMID: 12058902 DOI: 10.1016/s0021-9673(02)00171-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments and molecular simulations were carried out to study temperature effects (in the range of 323 to 383 K) on the absolute and relative retention of n-hexane, n-heptane, n-octane, benzene, toluene and the three xylene isomers in gas-liquid chromatography. Helium and squalane were used as the carrier gas and retentive phase, respectively. Both the experiments and the simulations show a markedly different temperature dependence of the retention for the n-alkanes compared to the arenes. For example, over the 60 K temperature range studied, the Kovats retention index of benzene is found to increase by about 16 or 18+/-10 retention index units determined from the experiments or simulations, respectively. For toluene and the xylenes, the experimentally measured increases are similar in magnitude and range from 14 to 17 retention index units for m-xylene to o-xylene. The molecular simulation data provide an independent method of obtaining the transfer enthalpies and entropies. The change in retention indices is shown to be the result of the larger entropic penalty and the larger heat capacity for the transfer of the alkane molecules.
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Affiliation(s)
- Collin D Wick
- Department of Chemistry, University of Minnesota, Minneapolis 55455, USA
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32
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Lebrón-Aguilar R, Quintanilla-López JE, García-Domínguez JA. Improving the accuracy of Kováts' retention indices in isothermal gas chromatography. J Chromatogr A 2002; 945:185-94. [PMID: 11860135 DOI: 10.1016/s0021-9673(01)01463-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Isothermal Kováts' retention indices are currently reported as whole numbers, and are frequently deduced from a linear least mean squares fitting of the logarithms of adjusted retention times of a number of n-alkanes versus carbon number, following an iterative method that minimises errors. The currently accepted accuracy is about one retention index unit for apolar stationary phases, and lower for polar stationary phases. This paper presents results that show how the accuracy of the retention index may be safely reported to one-tenth of a retention index unit by the use of a non-linear equation, with present day gas chromatographs without electronic flow controllers. Results are presented that prove the correctness of the retention indices found for several substances on one particular capillary column. Hints on the minimum retention times needed to achieve the 0.1 retention index accuracy are mentioned, for retention times recorded in minutes and in seconds. According to results of this paper, two chromatograms, run under the appropriate conditions, are sufficient to obtain the desired accuracy. The method proposed in this paper does not require knowledge of the hold-up time of the chromatogram.
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Affiliation(s)
- Rosa Lebrón-Aguilar
- Departamento de Química Analítica y Análisis Instrumental, Facultad de Ciencias, Universidad Autónoma de Madrid, Spain
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33
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Tarján G, Bitter I, Strasser B, Szatmáry M. Data for the gas-liquid chromatographic analysis of essential oils. Determination of the composition of the essential oil of Marjoram. Chromatographia 2002. [DOI: 10.1007/bf02494130] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Wick CD, Siepmann JI, Schure MR. Influence of Analyte Overloading on Retention in Gas−Liquid Chromatography: A Molecular Simulation View. Anal Chem 2001. [DOI: 10.1021/ac0108717] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Collin D. Wick
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, and Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Spring House, Pennsylvania 19477
| | - J. Ilja Siepmann
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, and Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Spring House, Pennsylvania 19477
| | - Mark R. Schure
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, and Theoretical Separation Science Laboratory, Rohm and Haas Company, 727 Norristown Road, Spring House, Pennsylvania 19477
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35
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Prediction of GC retention values under various column temperature conditions from temperature programmed data. Chromatographia 2001. [DOI: 10.1007/bf02491619] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Chapter 11D Analysis of chemicals related to the chemical weapons convention. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1567-7192(00)80065-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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37
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Martin MG, Siepmann JI, Schure MR. Simulating Retention in Gas−Liquid Chromatography. J Phys Chem B 1999. [DOI: 10.1021/jp9932822] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marcus G. Martin
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431
| | - J. Ilja Siepmann
- Departments of Chemistry and of Chemical Engineering and Materials Science, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431
| | - Mark R. Schure
- Theoretical Separation Science Laboratory, Rohm and Haas Company,727 Norristown Road, Spring House, Pennsylvania 19477
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38
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Tudor E. Analysis of the equations for the temperature dependence of the retention index. I. Relation between equations. J Chromatogr A 1999; 858:65-78. [PMID: 10544892 DOI: 10.1016/s0021-9673(99)00802-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The relation between the parameters of several equations for the retention index temperature dependence was established, taking the hyperbola deduced from the retention theory as starting point. The transformation factors depend only on methylene contributions to the thermodynamic functions of solution and temperature. Their evolution with the mean temperature of the range was illustrated for SE-30 and Carbowax-20M glass capillary columns. On this basis the post-run standardisation of dI/dT values at a reference mean temperature is possible. Examples and statistical correlation between series of parameters from different equations for perfumery solutes were shown.
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Affiliation(s)
- E Tudor
- Institute of Physical Chemistry I.G. Murgulescu, Romanian Academy, Bucharest, Romania
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39
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Tudor E, Moldovan D. Temperature dependence of the retention index for perfumery compounds on a SE-30 glass capillary column. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00412-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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40
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Tudor E, Oncescu T. Influence of temperature and n-alkane pair on the methylene increments to the thermodynamic functions of solution on SE-30 and Carbowax-20M capillary columns. J Chromatogr A 1999. [DOI: 10.1016/s0021-9673(99)00336-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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41
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42
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Lebrón-Aguilar R, Garcı́a-Domı́nguez JA, Quintanilla-López JE. Hold-up time in gas chromatography. J Chromatogr A 1998. [DOI: 10.1016/s0021-9673(98)00037-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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43
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44
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Didaoui L, Touabet A, Meklati BY. Comparison of mathemical methods for the calculation of retention indices at high temperature in gas chromatography. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/jhrc.1240201107] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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45
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46
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Tudor E. Temperature dependence of the retention index for perfumery compounds on a SE-30 glass capillary column I. Linear equations. J Chromatogr A 1997. [DOI: 10.1016/s0021-9673(97)00453-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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47
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Wang W, Zhang* X, Deng J, Lu P. Correlation of Kováts Retention Indices on Polar Stationary Phase with That on Non-polar Stationary Phase. ANAL LETT 1997. [DOI: 10.1080/00032719708001710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Wenling Wang
- a Department of Chemistry , Fudan University , Shanghai , 200433 , People's Republic of China
| | - Xiangmin Zhang*
- a Department of Chemistry , Fudan University , Shanghai , 200433 , People's Republic of China
| | - Jiaqi Deng
- a Department of Chemistry , Fudan University , Shanghai , 200433 , People's Republic of China
| | - Peichang Lu
- a Department of Chemistry , Fudan University , Shanghai , 200433 , People's Republic of China
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48
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Elvebak LE, Knowles V, Gray GR. Authentic standards for the reductive-cleavage method. The positional isomers of partially methylated and acetylated or benzoylated 1,5-anhydro-d-xylitol. Carbohydr Res 1997. [DOI: 10.1016/s0008-6215(97)00009-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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49
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Elvebak LE, Wittmeyer P, Gray GR. Authentic standards for the reductive-cleavage method. The positional isomers of partially methylated and acetylated or benzoylated 1,5-anhydro-l-rhamnitol. Carbohydr Res 1997. [DOI: 10.1016/s0008-6215(97)00008-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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50
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Evaluation of theoretical models of non electrolyte solutions in the prediction of Kováts retention indices of branched alkanes in alkane stationary phases. J Chromatogr A 1996. [DOI: 10.1016/s0021-9673(96)00568-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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