Enantioselective analysis of a heptacholorbornane isolated from the technical product melipax by gas chromatography/mass spectrometry
1997
Vetter, W. | Krock, B. | Klobes, U. | Luckas, B.
A heptachloro compound of technical toxaphene (CTT), recently isolated from the technical mixture Melipax, was enantioseparated by application of gas chromatography/mass spectrometry (GC/MS) with a chiral stationary phase. Using tert-butyldimethylsilylated beta-cyclodextrin and two different ionization techniques, the first eluted enantiomer of 2-exo,3-endo,5-exo,9,9,10,10-heptachlorobornane (B7-1453) was found in significantly more abundance. Furthermore, the enantiomeric ratio (ER) of 1.26 +/- 0.03 was reproduced after GC-ECD analysis on another chiral stationary phase, heptakis-(6-O-tert-butyldimethylsilyl- 2,3-di-O-methyl)-beta-cyclodextrin. This confirms that B7-1453 was not present in racemic composition in the technical product. At present it is not clear if other technical products also contain B7-1453 and other compounds in nonracemic composition. Several synthesized CTT standards, however, showed racemic composition. An ER of 1.0 for B7-1453 was determined in a cod liver extract. Assuming that B7-1453 was present in nonracemic composition in the source of contamination, the ER of 1.0 in the cod liver would have been the result of a faster degradation of the first eluted enantiomer, which finally led to an ER of 1.0. If the source of contamination contained B7-1453 in racemic composition, the cod did not degrade B7-1453 enantioselectively. In this case, enantioselective analysis of CTTs in biota may be used to find the source of contamination.
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