with regard to the enantiomeric distribution profile (ER) of B8-1413 (Parlar26),
B9-1679 (Parlar50) and B8-2229 (Parlar44). For all animals, the second eluting
enantiomer of B8-2229 was below 40% of the first eluting one (Table 8.13). Vetter
et al. also isolated B7-1453 from a Baltic cod (Gadus morhua L.) liver extract and
determined the ER with 1.0. This value has to be compared with the isolate from the
technical Melipax
® mixture, which exhibited an ER value of 1.26 Æ 0.03, as
mentioned above. In this special case, that is, application of an enantiomer-enriched
toxaphene congener, the alteration of the ER was owing to a faster transformation of
the first eluting enantiomer, which finally led to an ER of 1.0. According to the
authors’ conclusions, this spectacular result, enantioselective transformation leading
to equal amounts of both enantiomers, is the result of biotransformation of enantiomers with different reaction speeds, which accidentally led to an ER of 1.0. The
interpretation of this result would be erroneous, if synthetic (racemic) standards had
been used as a reference instead of the B7-1453 isolate from Melipax. It cannot be
excluded that a similar situation may be encountered in connection with other
toxaphene congeners. Therefore, caution has to be applied, when interpreting enantiomeric ratios of toxaphene congeners determined from environmental samples. In a
subsequent investigation, Vetter and co-workers confirmed the enantiomeric ratios
published for the four toxaphene congeners B7-1453 (Vetter et al. 1998a, b),
B8-1413 (Vetter et al. 1997a, b, c, d, e, f, B8-2229 (Vetter et al.
1997a, b, c, d, e, f) and B9-1679 (Vetter et al. 1997a, b, c, d, e, f) by carefully
studying and excluding co-elution effects and other artefacts that may have been
caused, for example, at least in the case of cGC/ECNI-MS application, as already
discussed in Chap. 7 (Vetter and Luckas 1998).
Klobes et al. succeeded in separating the enantiomers of toxaphene congener
B8-1412, a major component in biota, using a 30-m long column coated with 35%
heptakis(6-O-tertbutyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin diluted in
OV1701 (Klobes et al. 1998a, b, c). In all Atlantic cod liver samples from different
areas of the Baltic Sea, enantiomeric ratios of B8-1412 were significantly <
1 (Table 8.13). Both in blubber extracts from a grey seal grypus (FABR.) from
Iceland and in blubber extracts from a Weddell seal (Leptonychotes Weddeli LES.),
an ER of 0.4 was found. Although the number of samples investigated thus far is
low, the results obtained by Klobes et al. clearly indicate an enantioenriched
B8-1412 in all samples.
A Norwegian-Russian study reported the successful isolation and synthesis of a
major enantiomerically pure Toxaphene
® -related compound from the former soviet
pesticide Polychloropinene
® (Hansen et al. 2004). This enantiomerically pure potential congener (C 10 H 9 C l9 ) has been isolated from a reaction mixture obtained by the
free radical chlorination of (1S)-2-endo-chlorobornane and its absolute configuration
determined after crystallisation with X-ray crystallography. It crystallises in the
monoclinic space group C2 with two molecules in the asymmetric unit. This was
the first report of the preparation of a single enantiomer of a synthetic
polychloroterpene on a multi-milligram scale (Hansen et al. 2004).
As earlier reported, Garrison and co-workers were not able to verify any
enantioselectivity for the transformation of o,p-DDT to o,p
0 -DDD using the Elodea-water reaction medium (Garrison et al. 1997). By way of contrast,
8.2 Transformation/Accumulation of Chiral Xenobiotics in Higher Organisms
163
B9-1679 (Parlar50) and B8-2229 (Parlar44). For all animals, the second eluting
enantiomer of B8-2229 was below 40% of the first eluting one (Table 8.13). Vetter
et al. also isolated B7-1453 from a Baltic cod (Gadus morhua L.) liver extract and
determined the ER with 1.0. This value has to be compared with the isolate from the
technical Melipax
® mixture, which exhibited an ER value of 1.26 Æ 0.03, as
mentioned above. In this special case, that is, application of an enantiomer-enriched
toxaphene congener, the alteration of the ER was owing to a faster transformation of
the first eluting enantiomer, which finally led to an ER of 1.0. According to the
authors’ conclusions, this spectacular result, enantioselective transformation leading
to equal amounts of both enantiomers, is the result of biotransformation of enantiomers with different reaction speeds, which accidentally led to an ER of 1.0. The
interpretation of this result would be erroneous, if synthetic (racemic) standards had
been used as a reference instead of the B7-1453 isolate from Melipax. It cannot be
excluded that a similar situation may be encountered in connection with other
toxaphene congeners. Therefore, caution has to be applied, when interpreting enantiomeric ratios of toxaphene congeners determined from environmental samples. In a
subsequent investigation, Vetter and co-workers confirmed the enantiomeric ratios
published for the four toxaphene congeners B7-1453 (Vetter et al. 1998a, b),
B8-1413 (Vetter et al. 1997a, b, c, d, e, f, B8-2229 (Vetter et al.
1997a, b, c, d, e, f) and B9-1679 (Vetter et al. 1997a, b, c, d, e, f) by carefully
studying and excluding co-elution effects and other artefacts that may have been
caused, for example, at least in the case of cGC/ECNI-MS application, as already
discussed in Chap. 7 (Vetter and Luckas 1998).
Klobes et al. succeeded in separating the enantiomers of toxaphene congener
B8-1412, a major component in biota, using a 30-m long column coated with 35%
heptakis(6-O-tertbutyldimethylsilyl-2,3-di-O-methyl)-β-cyclodextrin diluted in
OV1701 (Klobes et al. 1998a, b, c). In all Atlantic cod liver samples from different
areas of the Baltic Sea, enantiomeric ratios of B8-1412 were significantly <
1 (Table 8.13). Both in blubber extracts from a grey seal grypus (FABR.) from
Iceland and in blubber extracts from a Weddell seal (Leptonychotes Weddeli LES.),
an ER of 0.4 was found. Although the number of samples investigated thus far is
low, the results obtained by Klobes et al. clearly indicate an enantioenriched
B8-1412 in all samples.
A Norwegian-Russian study reported the successful isolation and synthesis of a
major enantiomerically pure Toxaphene
® -related compound from the former soviet
pesticide Polychloropinene
® (Hansen et al. 2004). This enantiomerically pure potential congener (C 10 H 9 C l9 ) has been isolated from a reaction mixture obtained by the
free radical chlorination of (1S)-2-endo-chlorobornane and its absolute configuration
determined after crystallisation with X-ray crystallography. It crystallises in the
monoclinic space group C2 with two molecules in the asymmetric unit. This was
the first report of the preparation of a single enantiomer of a synthetic
polychloroterpene on a multi-milligram scale (Hansen et al. 2004).
As earlier reported, Garrison and co-workers were not able to verify any
enantioselectivity for the transformation of o,p-DDT to o,p
0 -DDD using the Elodea-water reaction medium (Garrison et al. 1997). By way of contrast,
8.2 Transformation/Accumulation of Chiral Xenobiotics in Higher Organisms
163