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Bizzo HR, Brilhante NS, Nolvachai Y, Marriott PJ. Use and abuse of retention indices in gas chromatography. J Chromatogr A 2023; 1708:464376. [PMID: 37717451 DOI: 10.1016/j.chroma.2023.464376] [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: 05/02/2023] [Revised: 09/07/2023] [Accepted: 09/09/2023] [Indexed: 09/19/2023]
Abstract
The value of the concept of retention indices (RI) to the practice of gas chromatography (GC) is highlighted, where the RI of a compound is one component of the strategy to identify the compound. The widespread reliance on GC and then on mass spectrometry for 'identification', may result in inadequate confirmation of molecular identity. However, RI do provide a useful tentative indication of the possible molecule(s). Thus, the RI value is a useful first measure of the molecule identity, and shown here to be valuable provided limitations are recognised. An author has a responsibility to correctly calculate the index and then use the values for (tentative) identification. Tables of reference RI values are useful in this respect, but finding an 'exact match' RI value does not confirm the identity. Hence, it is necessary to understand how the RI value may be incorrectly used in this respect. The reviewer of written research is charged with ensuring the index values are applied in a rigorous manner. Selected case studies from our own work, support the care that must be exercised when reporting RI values. In terms of advanced GC operations, mention is made of multidimensional gas chromatography and comprehensive two-dimensional gas chromatography to acquire RI values on both the first and second columns in the two-column separation experiment.
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Affiliation(s)
- Humberto R Bizzo
- Embrapa Agroindústria de Alimentos - Avenida das Américas, 29501, Rio de Janeiro, RJ 23020-470, Brazil; Universidade Federal do Rio de Janeiro - Avenida Athos da Silveira Ramos, 149, Rio de Janeiro, RJ 21945-970, Brazil
| | - Nathália S Brilhante
- Universidade Federal do Rio de Janeiro - Avenida Athos da Silveira Ramos, 149, Rio de Janeiro, RJ 21945-970, Brazil
| | - Yada Nolvachai
- CASS Food Research Centre, School of Exercise and Nutritional Sciences, Faculty of Health, Deakin University, Burwood 3125, Victoria, Australia
| | - Philip J Marriott
- Australian Centre for Research on Separation Science, School of Chemistry, Monash University, Wellington Road, Clayton, VIC 3800, Australia.
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Huang Y, Lu JW, Xie Y, Hong C, Shi L, Hai J. Process tracing of PCDD/Fs from economizer to APCDs during solid waste incineration: Re-formation and transformation mechanisms. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 120:839-847. [PMID: 33268046 DOI: 10.1016/j.wasman.2020.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 08/31/2020] [Accepted: 11/11/2020] [Indexed: 06/12/2023]
Abstract
The emission of PCDD/Fs is a crucial factor for the aggravation of the Not-In-My-Back-Yard (NIMBY) syndrome, especially for the incineration plants that fail to meet the emission standard. It is well known that physicochemical processes in the boiler can notably affect the discharge of dioxins, especially under transient, non-steady conditions. However, few studies paid attention to the important operational parameters that influence PCDD/Fs formation and transformation in the boiler when an incinerator is in its daily steady operation. In this study, 36 samples were analyzed to achieve process tracing of PCDD/Fs. The concentration, congener profile and vapor/solid partitions of PCDD/Fs from the economizer to air pollution control devices (APCDs) under two typical steady conditions were investigated. Results indicated that increasing air supply aggravated the formation of PCDD/Fs, disturbed the vapor/solid partitions, and triggered a substandard emission. Quantitative structure-activity relationship (QSAR) modeling was firstly performed for the formation mechanism and orbital energy factors were identified as dominating factors. Besides, the removal rates of PCDD/Fs significantly correlated with the saturated vapor pressure and proportions of different isomers. This study is beneficial for operators to optimize relevant operational parameters of the incineration plants so as to get rid of substandard problems.
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Affiliation(s)
- Yuanqing Huang
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Jia-Wei Lu
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Technology and Equipment, Guangzhou 510330, China.
| | - Yingshi Xie
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Technology and Equipment, Guangzhou 510330, China
| | - Chengyang Hong
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Lizheng Shi
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Jing Hai
- South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; Guangdong Province Engineering Laboratory for Solid Waste Technology and Equipment, Guangzhou 510330, China.
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Experimental determination of thermodynamic properties of terpene and aromatic ketones by gas chromatography. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2020.114531] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Kim HS, Lee DS. Proximity to chemical equilibria among air, water, soil, and sediment as varied with partition coefficients: A case study of polychlorinated dibenzodioxins/furans, polybrominated diphenyl ethers, phthalates, and polycyclic aromatic hydrocarbons. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 670:760-769. [PMID: 30921709 DOI: 10.1016/j.scitotenv.2019.03.286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
To capture the pollutant distribution status among environmental media and to understand how the distribution varies with the pollutants' properties, we assessed a total of 225 fugacity ratios (FRs) of 45 semi-volatile organic compounds (SVOCs) (polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs), polybrominated diphenyl ethers (PBDEs), phthalates, and polycyclic aromatic hydrocarbons (PAHs)) for five medium pairs (air-water, air-soil, water-sediment, soil-water, and soil-sediment) using the nationwide multimedia monitoring data. For many of the pollutants, fugacity was greatest in air (PCDFs and 6 heavy PAHs) and in sediment (PBDEs and 9 light PAHs) while lowest in soil for most of the pollutants. PAHs and phthalates appeared to be farther away from equilibrium than PCDDs/Fs and PBDEs. The ratios of "equilibrium improbable" FRs to all the FRs in each chemical group were 2%, 0%, 33.3%, and 28.9% for PCDDs/Fs, PBDEs, phthalates, and PAHs, respectively. FRwater/air of PAHs, FRsoil/air, and FRsediment/water of the pollutant groups (except for PBDEs) decreased significantly (p < 0.01) with the partition coefficients, 1/Kair/water (1/Kaw), Koctanol/air (Koa), and Koctanol/water (Kow), respectively, even in the field conditions. The findings on FRs values provide valuable clues to identifying the media that would act as sink or source for certain chemicals and to using a more appropriate choice in the coherence test of environmental quality objectives, which should be important considerations in the management of chemical contamination in the environment.
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Affiliation(s)
- Hee Seok Kim
- Department of Environmental Planning & Environmental Planning Institute, Graduate School of Environmental Studies, Seoul National University, Seoul 08826, South Korea
| | - Dong Soo Lee
- Department of Environmental Planning & Environmental Planning Institute, Graduate School of Environmental Studies, Seoul National University, Seoul 08826, South Korea.
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Trinh MM, Tsai CL, Hien TT, Thuan NT, Chi KH, Lien CG, Chang MB. Atmospheric concentrations and gas-particle partitioning of PCDD/Fs and dioxin-like PCBs around Hochiminh city. CHEMOSPHERE 2018; 202:246-254. [PMID: 29571145 DOI: 10.1016/j.chemosphere.2018.03.087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/10/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Atmospheric PCDD/Fs and dl-PCBs samples were collected in Hochiminh city, Vietnam to address the effect of meteorological parameters, especially rainfall, on the occurrence and gas/particle partitioning of these persistent organic pollutants. The results indicate that PCDD/Fs and dl-PCBs concentrations in industrial site are higher than those measured in commercial and rural sites during both rainy and dry seasons. In terms of mass concentration, ambient PCDD/F levels measured in dry season are significantly higher than those measured in rainy season while dl-PCB levels do not vary significantly between rainy and dry seasons. The difference could be attributed to different gas/particle partitioning characteristics between PCDD/Fs and dl-PCBs. PCDD/Fs are found to be mainly distributed in particle phase while dl- PCBs are predominantly distributed in gas phase in both rainy and dry seasons. Additionally, Junge-Pankow and Harner-Bidleman models are applied to better understand the gas/particle partitioning of these pollutants in atmosphere. As a results, both PCDD/Fs and dl-PCBs are under non-equilibrium gas/particle partitioning condition, and PCDD/Fs tend to reach equilibrium easier in rainy season while there are no clear trend for dl-PCBs. Harner-Bidleman model performs better in evaluating the gas/particle partitioning of PCDD/Fs while Junge-Pankow model results in better prediction for dl-PCBs.
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Affiliation(s)
- Minh Man Trinh
- Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan.
| | | | - To Thi Hien
- Faculty of Environment, University of Science, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam.
| | - Ngo Thi Thuan
- Faculty of Environment, University of Science, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam.
| | - Kai Hsien Chi
- Institute of Environmental and Occupational Health Sciences, National Yang Ming University, Taipei, Taiwan.
| | - Chien Guo Lien
- Institute of Environmental and Occupational Health Sciences, National Yang Ming University, Taipei, Taiwan.
| | - Moo Been Chang
- Graduate Institute of Environmental Engineering, National Central University, Chungli, Taiwan.
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Qin Y, Zhu H, Zhang M, Zhang H, Xiang C, Li B. GC-MS Analysis of Membrane-Graded Fulvic Acid and Its Activity on Promoting Wheat Seed Germination. Molecules 2016; 21:molecules21101363. [PMID: 27754395 PMCID: PMC6273670 DOI: 10.3390/molecules21101363] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 09/25/2016] [Accepted: 10/09/2016] [Indexed: 11/16/2022] Open
Abstract
The chemical composition of fulvic acid (FA) with a molecular weight below 500 (FA-500) was analyzed, and its activity on promoting the seed germination of wheat was studied in this paper. The FA-500 was obtained by membrane separation technology and qualitatively and quantitatively analyzed by using gas chromatography-mass spectrometry combined with the retention index. Forty-seven constituents were identified, including structures with ester, acid and alcohol groups, which accounted for 95% of the total composition. The highest relative content of compounds was diethyl succinate and diethyl malonate, accounting for 29% and 17% of the total, respectively. Yannong 19 and Luyuan 301 wheat seeds were steeped with the FA-500 solution of different concentration respectively for two hours. Several markers were assessed: germination rate, coleoptile and radicle length, germination index, vitality index and the activity of α-amylase and (α+β) amylase. The results indicated that FA-500 had a significant effect on promoting seed germination within an appropriate concentration range. The best concentration was 0.5‰, and an inhibiting effect would appear with the increase of concentration. In the process of seed germination, FA-500 may affect the growth of the seed through influencing the amylase activity, which was related to respiration.
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Affiliation(s)
- Yi Qin
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Hui Zhu
- School of Chemistry and Chemical Engineering, Sichuan University of Arts and Science, Dazhou 635000, China.
| | - Mi Zhang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Huifen Zhang
- Food Security Research Institute of Yunnan Province, Kunming University of Science and Technology, Kunming 650500, China.
| | - Cheng Xiang
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
| | - Baocai Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
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Wilczyńska-Piliszek AJ, Piliszek S, Falandysz J. Use of quantitative-structure property relationship (QSPR) and artificial neural network (ANN) based approaches for estimating the octanol-water partition coefficients of the 209 chlorinated trans-azobenzene congeners. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2012; 47:111-128. [PMID: 22251211 DOI: 10.1080/03601234.2012.616779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Polychlorinated azobenzenes (PCABs) can be found as contaminant by products in 3,4-dichloroaniline and its derivatives and in the herbicides Diuron, Linuron, Methazole, Neburon, Propanil and SWEP. Trans congeners of PCABs are physically and chemically more stable and so are environmentally relevant, when compared to unstable cis congeners. In this study, to fulfill gaps on environmentally relevant partitioning properties of PCABs, the values of n-octanol/water partition coefficients (log K(OW)) have been determined for 209 congeners of chloro-trans-azobenzene (Ct-AB) by means of quantitative structure-property relationship (QSPR) approach and artificial neural networks (ANN) predictive ability. The QSPR methods used based on geometry optimalization and quantum-chemical structural descriptors, which were computed on the level of density functional theory (DFT) using B3LYP functional and 6-311++G basis set in Gaussian 03 and of the semi-empirical quantum chemistry method (PM6) of the molecular orbital package (MOPAC). Polychlorinated dibenzo-p-dioxins (PCDDs), -furans (PCDFs) and -biphenyls (PCBs), to which PCABs are related, were reference compounds in this study. An experimentally obtained data on physical and chemical properties of PCDD/Fs and PCBs were reference data for ANN predictions of log K(OW) values of Ct-ABs in this study. Both calculation methods gave similar results in term of absolute log K(OW) values, while the models generated by PM6 are considered highly efficient in time spent, when compared to these by DFT. The estimated log K(OW) values of 209 Ct-ABs varied between 5.22-5.57 and 5.45-5.60 for Mono-, 5.56-6.00 and 5.59-6.07 for Di-, 5.89-6.56 and 5.91-6.46 for Tri-, 6.10-7.05 and 6.13-6.80 for Tetra-, 6.43-7.39 and 6.48-7.14 for Penta-, 6.61-7.78 and 6.98-7.42 for Hexa-, 7.41-7.94 and 7.34-7.86 for Hepta-, 7.99-8.17 and 7.72-8.20 for Octa-, 8.35-8.42 and 8.10-8.62 for NonaCt-ABs, and 8.52-8.60 and 8.81-8.83 for DecaCt-AB. These log K(OW) values shows that Ct-ABs are compounds of relatively low environmental mobility (log K(OW) > 4.5) and of significant bioaccumulation potential.
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Affiliation(s)
- Agata J Wilczyńska-Piliszek
- Research Group of Environmental Chemistry, Ecotoxicology & Food Toxicology, Institute of Environmental Sciences & Public Health, University of Gdańsk, Gdańsk, Poland
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Saçan MT, Ozkul M, Erdem SS. Physico-chemical properties of PCDD/PCDFs and phthalate esters. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2005; 16:443-59. [PMID: 16272043 DOI: 10.1080/10659360500320602] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
QSPR models for water solubility (S), n-octanol/water partition coefficient (K(OW)), and Henry's law constant (H) for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzo-p-furans (PCDFs) and phthalates have been established based on two different sets of parameters. Those parameters were topology based characteristic root index (CRI) and three semi-empirical molecular descriptors, namely--energies of the highest occupied and the lowest unoccupied molecular orbital (E(HOMO) and E(LUMO)), and dipole moment (mu). The best fit equation found by "forward multiple linear regression" showed that the topology based CRI was the most important parameter for the modelling of solubility and n-octanol/water partition coefficient. For n-octanol/water partition coefficient a two-parameter equation including the CRI and E(HOMO) with a correlation coefficient of r = 0.992 was obtained whereas a three-parameter equation for solubility and Henry's law constant including the CRI, E(LUMO) and mu with a correlation coefficient of r = 0.986 and r = 0.933 was obtained, respectively. E(HOMO) and mu didn't appear in the same model because of the collinearity. The results of modified jackknife tests indicated that the three models were statistically robust. Mean deviation of calculated values from experimental data amounted to 0.27, 0.17, and 0.28 log units for the three properties mentioned. The developed models have been used to predict the S, K(OW) and H of compounds not included in the training sets.
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Affiliation(s)
- M T Saçan
- Boğaziçi University, Institute of Environmental Sciences, 34342 Bebek, Istanbul, Turkey.
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Hoskovec M, Grygarová D, Cvaeka J, Streinz L, Zima J, Verevkin SP, Koutek B. Determining the vapour pressures of plant volatiles from gas chromatographic retention data. J Chromatogr A 2005; 1083:161-72. [PMID: 16078703 DOI: 10.1016/j.chroma.2005.06.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The frequently used vapour pressure versus Kováts retention index relationship has been evaluated in terms of its universal applicability, highlighting the problems associated with predicting the vapour pressures of structurally divergent organic compounds from experimentally measured isothermal Kováts retention indices. Two models differing in approximations adopted to express the activity coefficient ratio have been evaluated using 32 plant volatiles of different structural types as a test set. The validity of these models was established by checking their ability to reproduce 22 vapour pressures known from independent measurements. Results of the comparison demonstrated that (i) the original model, based on the assumption of equal activity coefficients for the test and reference substances, led, as expected, to a poor correlation (r2 = 89.1% only), with significantly deviating polar compounds and (ii) the model showed significant improvement after incorporating a new empirical term related to vaporization entropy and boiling point. The addition of this term allowed more than 99% of the vapour pressure variance to be accounted for. The proposed model compares favourably with existing correlations, while having an added advantage of providing a convenient tool for vapour pressure determination of chemically divergent chemicals.
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Affiliation(s)
- Michal Hoskovec
- Department of Natural Products, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
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Ding GH, Chen JW, Qiao XL, Huang LP, Lin J, Chen XY. Comparison of subcooled liquid vapor pressures of polychlorinated dibenzo-p-dioxins and dibenzofurans predicted by QSPR and GC-RI methods. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2005; 16:301-12. [PMID: 16234172 DOI: 10.1080/10659360500204525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Subcooled liquid vapor pressures (P(L)) are of great importance for assessing the persistent behavior of organic pollutants. As P(L) cannot be determined by direct experiments, it is of interest to develop and evaluate various predictive methods. In the current study, gas chromatography retention index (GC-RI) and quantitative structure-property relationship (QSPR) methods were used to develop predictive models for P(L) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). The model development was based on P(L) values converted from consistent experimental solid vapor pressures (P(S)). The P(L) values predicted by the two methods are highly consistent with each other, and in-between sets of values predicted by others. Since the QSPR method can be regarded as independent of experiments, and can be used to interpret intermolecular interactions that govern the magnitude of P(L), it may be superior to the GC-RI method.
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Affiliation(s)
- G H Ding
- Dalian University of Technology, Department of Environmental Science and Technology, Linggong Road 2, Dalian 116024, China
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Zhai Z, Wang Z, Wang L. Quantitative structure–property relationship study of GC retention indices for PCDFs by DFT and relative position of chlorine substitution. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.theochem.2005.03.025] [Citation(s) in RCA: 9] [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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