Gas chromatographic enantiomer separation of agrochemicals and polychlorinated biphenyls (PCBs) using modified cyclodextrins

Abstract

SummaryThe enantiomers of the polychlorinated polycyclic xenobiotics heptachlor, cis-and trans-chlordane, cis-and trans-heptachlorepoxide, oxychlordane, and bromocyclen have been resolved by gas chromatography with selectively substituted cyclodextrins. The order of elution of these compounds and of a-hexachlorocyclohexane (a-HCH) was determined by comparison with enantiomerically enriched reference compounds obtained by preparative enantioselective gas chromatography.A separation of the eight stereoisomers of the pyrethroid insecticide allethrin into seven peaks was achieved. Both trans-diastereomers were separated into their enantiomers and the order of elution could be determined by comparison with commercially available (S)-bioallethrin and trans-bioallethrin. Also one cis-diastereomer was separated, wheras the other cis-isomer could not be resolved. In addition 15 out of 19 stable atropisomeric polychlorinated biphenyls with 5, 6 and 7 chlorine substituents, some chiral organophosphorus pesticides, including acephate and malaoxon and the herbicide bromoacil were separated.

Gas chromatographic separation of chiral organochlorines on modified cyclodextrin phases and results of marine biota samples

“…The former is an important metabolite of heptachlor in higher organisms. The temperature program which simultanously separated the enantiomers of cis-and transchlordane, oxychlordane, a-HCH, a-PDHCH, p-and y-PCCH partly resolved the heptachlorexopides (see Table 1 and Hardt et al baseline separated standard solutions of heptachlor and cis-heptachlorepoxide on heptakis(2,6-di-O-methyl-3-O-npenty1)-P-cyclodextrin [33]. Recently, the chiral separation of cis-heptachlorepoxide in biota was obtained on the heptakis(2-O-methyl-3,6-di-O-n-pentyl)-~-cyclodextrin by Pfaffenberger et al [34].…”

Chiral analysis for environmental applications

“…Lipodex E a-HCH, trans-chlordane, PCB95, PCB136 [13] Octakis(2,6-methyl-3-pentyl)-g-cyclodextrin (in 80% OV1701) -a-HCH, cis-chlorane, trans-chlordane [9] Heptakis(2,6-methyl-3-pentyl)-b-cyclodextrin (in 80% OV1701) -Heptachlor, cis-heptachlorepoxide [9] Heptakis(2,3,6-trimethyl)-b-cyclodextrin with some tert-butyldimethyl substituents -…”

“…Currently chiral GC is used, for example, to determine whether or not chiral synthetic fragrances such as polycyclic musk fragrances are possibly biodegraded or whether ad- [9], dimethenamid, metalaxyl, metolachlor [6], HHCB, AHTN [10] ATII, AHDI [6] o,p¢-DDT [11], methylated mecoprop [12] Octakis(3-O-butyryl-2,6-di-O-pentyl)-g-cyclodextrin in 50% OV1701…”

Enantiomeric separations of chiral polychlorinated biphenyls on three polysaccharide-type chiral stationary phases by supercritical fluid chromatography

“…All 19 chiral PCBs have been completely or partially separated by GC using a variety of chiral columns [11][12][13][14][15][16][17][18]. All these chiral PCBs except PCB 174 can also be separated by various kinds of cyclodextrin-modified MEKC approaches [5,[19][20][21].…”