Gas Chromatographic Enantiomer Separation of Polychlorinated Biphenyls (PCBs): Methods, Metabolisms, Enantiomeric Composition in Environmental Samples and their Interpretation

Vetter, Walter

doi:10.1002/ijch.201600089

Cited by 9 publications

(5 citation statements)

References 117 publications

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“…Chromatographic stopped-flow techniques have been used to monitor enantiomerization studies [168]. All the works with GC described direct enantioselective methods using cyclodextrin-based CSP, the CSP most often applied in enantioselective analysis of organochlorine compounds [169,170]. Enantioselective LC-MS/MS methods performed direct chiral analysis, mostly using polysaccharide-based CSP [21,123,130,152,153], although the utilization of a cyclodextrin-based CSP was also described [131].…”

Section: Biodegradation Studies Of Chiral Pesticidesmentioning

confidence: 99%

Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

et al. 2017

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Abstract:The importance of stereochemistry for medicinal chemistry and pharmacology is well recognized and the dissimilar behavior of enantiomers is fully documented. Regarding the environment, the significance is equivalent since enantiomers of chiral organic pollutants can also differ in biodegradation processes and fate, as well as in ecotoxicity. This review comprises designed biodegradation studies of several chiral drugs and pesticides followed by enantioselective analytical methodologies to accurately measure the enantiomeric fraction (EF). The enantioselective monitoring of microcosms and laboratory-scale experiments with different environmental matrices is herein reported. Thus, this review focuses on the importance of evaluating the EF variation during biodegradation studies of chiral pharmaceuticals, drugs of abuse, and agrochemicals and has implications for the understanding of the environmental fate of chiral pollutants.

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Section: Biodegradation Studies Of Chiral Pesticidesmentioning

confidence: 99%

Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

et al. 2017

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“… 13 , 16 , 24 , 25 In addition, chiral OH-PCBs can theoretically be formed by oxidation of axially prochiral PCB congeners with three or four ortho chlorine substituents. 21 Axially prochiral PCB congeners have one phenyl ring with an unsymmetrical chlorine substitution pattern and a second phenyl ring with a symmetrical chlorine substitution pattern (i.e., 2,6; 3,5; 2,4,6; 3,4,5; 2,3,5,6; and 2,4,3,4,5,6). Introduction of a hydroxyl group in the meta or ortho position breaks the symmetry of this ring, thus resulting in axially chiral molecules.…”

Section: Introductionmentioning

confidence: 99%

“…Like their parent compounds, OH-PCBs with three or four ortho chlorine substituents and an unsymmetrical substitution pattern in both phenyl rings relative to the phenyl–phenyl bond are axially chiral. − These OH-PCBs and other PCB metabolites exist under ambient conditions as stable rotational isomers, or atropisomers, that are non-superimposable mirror images of each other . Chiral OH-PCBs can be formed by the oxidation of a chiral PCB congener.…”

Section: Introductionmentioning

confidence: 99%

“…Considerable evidence demonstrates that plants, such as poplar, , and mammals ,, metabolize chiral PCBs in a congener and species-dependent manner to chiral OH-PCBs. P450 enzyme-mediated metabolism in mammals, such as rats and mice, results in nonracemic chiral signatures of these OH-PCB metabolites in vitro and in vivo. ,,, In addition, chiral OH-PCBs can theoretically be formed by oxidation of axially prochiral PCB congeners with three or four ortho chlorine substituents . Axially prochiral PCB congeners have one phenyl ring with an unsymmetrical chlorine substitution pattern and a second phenyl ring with a symmetrical chlorine substitution pattern (i.e., 2,6; 3,5; 2,4,6; 3,4,5; 2,3,5,6; and 2,4,3,4,5,6).…”

Section: Introductionmentioning

confidence: 99%

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Microsomal Metabolism of Prochiral Polychlorinated Biphenyls Results in the Enantioselective Formation of Chiral Metabolites

Uwimana

Maiers

et al. 2017

Environ. Sci. Technol.

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Polychlorinated biphenyl (PCB) congeners with multiple ortho chlorine substituents and their metabolites exist as stable rotational isomers, or atropisomers, that are nonsuperimposable mirror images of each other. Additionally, the oxidation of certain axially prochiral PCBs, such as 2,2′,4,6′-tetrachlorobiphenyl (PCB 51) and 2,2′,4,5,6′-pentachlorobiphenyl (PCB 102), in the meta position of the symmetrically substituted phenyl ring is expected to form axially chiral hydroxylated metabolites (OH-PCBs); however, the formation of chiral OH-PCBs from prochiral PCBs has not been demonstrated experimentally. Here, we investigate if the oxidation of PCB 51 and PCB 102 by different microsomal preparations results in the formation of chiral OH-PCBs. Gas chromatographic analysis revealed that PCB 51 and PCB 102 were metabolized to 2,2′,4,6′-tetrachlorobiphenyl-3′-ol (OH-PCB 51) and 2,2′,4,5,6′-pentachlorobiphenyl-3′-ol (OH-PCB 102), respectively, by liver microsomes from male rats pretreated with different inducers; untreated male monkeys, guinea pigs, rabbits, and hamsters; and female dogs. The formation of both metabolites was inducer- and species-dependent. Both OH-PCB 51 and OH-PCB 102 were chiral and formed enantioselectively by all microsomal preparations investigated. These findings demonstrate that axially chiral PCB metabolites are formed from axially prochiral PCB congeners, a fact that should be considered when studying the environmental fate, transport, and toxicity of OH-PCBs.

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“…In an achiral environment, enantiomers have identical properties except for their chiroptics (polarimetry, circular dichroism (CD) and optical rotatory dispersion (ORD)). The stereogenic unit is frequently generated by a tetrahedron carbon include liquid chromatography (LC) [42], GC [43,44], capillary electrophoresis (CE), supercritical fluid chromatography (SFC), among others [45][46][47]. Among these technologies, chromatography has been the most used technique for the analysis of chiral pollutants, by two different approaches: direct and indirect methods [48,49].…”

Section: Basic Concepts Of Chiralitymentioning

confidence: 99%

Occurrence of Chiral Bioactive Compounds in the Aquatic Environment: A Review

Ribeiro

Maia

et al. 2017

Symmetry

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Abstract:In recent decades, the presence of micropollutants in the environment has been extensively studied due to their high frequency of occurrence, persistence and possible adverse effects to exposed organisms. Concerning chiral micropollutants in the environment, enantiomers are frequently ignored and enantiomeric composition often neglected. However, enantioselective toxicity is well recognized, highlighting the need to include enantioselectivity in environmental risk assessment. Additionally, the information about enantiomeric fraction (EF) is crucial since it gives insights about: (i) environmental fate (i.e., occurrence, distribution, removal processes and (bio)degradation); (ii) illicit discharges; (iii) consumption pattern (e.g., illicit drugs, pharmaceuticals used as recreational drugs, illicit use of pesticides); and (iv) enantioselective toxicological effects. Thus, the purpose of this paper is to provide a comprehensive review about the enantioselective occurrence of chiral bioactive compounds in aquatic environmental matrices. These include pharmaceuticals, illicit drugs, pesticides, polychlorinated biphenyls (PCBs) and polycyclic musks (PCMs). Most frequently analytical methods used for separation of enantiomers were liquid chromatography and gas chromatography methodologies using both indirect (enantiomerically pure derivatizing reagents) and direct methods (chiral stationary phases). The occurrence of these chiral micropollutants in the environment is reviewed and future challenges are outlined.

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Gas Chromatographic Enantiomer Separation of Polychlorinated Biphenyls (PCBs): Methods, Metabolisms, Enantiomeric Composition in Environmental Samples and their Interpretation

Cited by 9 publications

References 117 publications

Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

Chiral Analysis of Pesticides and Drugs of Environmental Concern: Biodegradation and Enantiomeric Fraction

Microsomal Metabolism of Prochiral Polychlorinated Biphenyls Results in the Enantioselective Formation of Chiral Metabolites

Occurrence of Chiral Bioactive Compounds in the Aquatic Environment: A Review

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