Production of toxaphene enantiomers by enantioselective HPLC after isolation of the compounds from an anaerobically degraded technical mixture

Enantiomers of 12 chlorobornanes were separated on a chiral stationary HPLC phase. The investigated compounds included relevant chlorobornanes in tech nical toxaphene (Toxicant A and an unknown heptachlorobornane), anaerobical ly mediated media such as sediment, soil, and sewage sludge (B6-923, B7-100 1), as well as eight persistent compounds of technical toxaphene (CTTs) fre quently detected in biological samples (B7-1000, B7-1453, B8-1412, B8-1413 or P-26; B8-1414 or P-40, B8-1945 or P-41, B8-2229 or P-44, and B9-1679 or P-50). Sufficient amounts of these 12 CTTs were not commercially available and had to be produced in our lab. Eight CTTs were obtained from sewage slu dge that was spiked with technical toxaphene and kept under anaerobic condi tions for four weeks. The samples were extracted with hexane followed by RP -HPLC fractionation. The resulting toxaphene pattern was significantly simp ler than that of the technical mixture. CTTs that showed intense fragmentat ion in GC/ECNI-MS were preferably metabolized. Moreover, only one of the di astereomers that make Toxicant A (B8-806/B8-809 or P-42a/b) resisted degrad ation in sewage sludge. We found that the persistent component of Toxicant A is 2,2,5-endo,6-exo,8,9,9,10-octachlorobornane (B8-809 or P-42b). B9-1679 (P-50), B7-1453, and B8-1412 were earlier isolated from biological samples , and B7-1000 was isolated from naturally contaminated sediments. The fract ions obtained after these procedures were suitable for enantioselective HPL C separations. The first eluting enantiomer was usually obtained as an enan tiopure standard whereas the second eluting enantiomer also contained the o ther enantiomer. Attempts to determine the optical rotation with the help o f a chiral HPLC detector failed. Elution orders of the enantiomers were est ablished an three GC chiral stationary phases. Only the enantiomers of B7-1 453 and B8-1945 (P-41) eluted in the same order from all CSPs while the oth ers showed different enantiomer elution orders or were not resolved on one of the chiral GC stationary phases. The knowledge and consideration of thes e results is important for the interpretation of enantiomer ratios found in biological samples and comparison of literature data.