Enantiomeric fractions

Warner, N.A., Norstrom, R.J., Wong, C.S. and Fisk, A.T. (2005) Enantiomeric fractions of chiral polychlorinated biphenyls provide insights on biotransformation capacity of Arctic biota. Environ Toxicol Chem, 24, 2763-2767. 

Fisk, A.T., Moisey, J., Hobson, K.A., Karnovsky, N.J., Norstrom, R.J., 2001. Chlordane components and metabolites in seven species of Arctic seabirds from the Northwater Polynya relationships with stable isotopes of nitrogen and enantiomeric fractions of chiral components. Environ. Pollut. 113, 225-238. 

Bordajandi, L. R., Ahad, E., Gonzalez, M. J. (2008) Occurrence of PCBs, PCDD/Fs, PBDEs and DDTs in Spanish hreast milk enantiomeric fraction of chiral PCBs. Chemosphere, 70 567-575. 

Figure 4.12 Reductive dechlorination of PCB 132 enantiomers and products in laboratory microcosms of Lake Hartwell sediments over time concentrations (A-C), enantiomer fractions for PCBs 132 (D) and 91 (E). Autoclaved control with racemic PCB 132 added (open circles, crosshatched bars), live treatments with racemic 132 added (filled circles, filled bars). Racemic value of EF —0.5 denoted by dashed line. (Reproduced with permission from Environmental Science and Technology, Changes in Enantiomeric Fractions during Microbial Reductive Dechlorination of PCB 32, PCB 149, and Arocior 1254 In Lake Hartwell Sediment Microcosms, by Usarat Pakdeesusuk, W. jack Jones et al., 37(6), 1100-1107. Copyright (2003) American Chemical Society)...

Harju, M. Bergman, A. Olsson, M. Roos, A. Haglund, P, Determination of atropisomeric and planar polychlorinated biphenyls, their enantiomeric fractions and tissue distribution in grey seals using comprehensive 2D gas chromatography J. Chromatogr. A 2003,1019, 127-142. 

Marvin, C.H. Macinnis, G. Alaee, M. Arsenault, G. Tomy, G.T., Factors influencing enantiomeric fractions of hexabromocyclododecane measured using liquid chromatography/ tandem mass spectrometry Rapid Commurt. Mass Spectrom. 2007, 21, 1925-1930. 

G6mara, B. Gonzalez, M.J., Enantiomeric fractions and congener specific determination of polychlorinated biphenyls in eggs of predatory birds from Donana National Park (Spain) Chemosphere 2006, 63, 662-669. 

The thermal stability and degradation rate of PLA and the formation rate, total yield and enantiomeric fractions of LA depend on a variety of factors (i) the molecular structure, (ii) the type and concentration of initiator, co-initiator, catalyst, and additive, (iii) the concentration of LA and water in PLA, and (iv) the method and reaction conditions including the pressure of the surrounding gas, temperature, and time [157, 273-278]. 

Wong et al. [33] studied the enantiomeric composition of polychlorinated biphenyl (PCB) enantiomers in rivers from selected sites throughout the United States. Nonracemic enantiomeric fractions (EFs) were observed for PCBs 91, 95, 136 and 149 in aquatic samples. Bromocyclen, a new insecticide with a low toxicity to mammals, is currently in use in Europe for the treatment of domestic animals against ectoparasites. Therefore, bromocyclen has been reported in the waters of the Stor river, a tributary of the River Elbe in northern Germany [34-36]. Franke et al. [37] reported chlorinated bis(propyl)ethers in the waters of the River Elbe. Three isomers of bis(propyl)ethers have been reported in different parts of the river, and the authors identified an epichlorohydrin production site, close to the Czech border, as the source of this contamination. Many toxic pesticides, such as BHC, aldrin, dieldrin, DDT and so on, have been detected in the Yamuna River, which is a very important river in India [38], Similarly, DDT, BHC, aldrin, dieldrin, malathion and so on have also been detected in another very famous river, the Ganges [39]. Recently, Ali and Jain [40] have reported the presence of lindane, malathion, BHC, p,p -DDD, o,p -DDT and methoxychlor in the Hindon River, also in India. 

To examine the influence of diet and age on organochlorine (OC) contaminant concentrations in two closely related ringed seal populations, enantiomeric fractions of chiral contaminants and stable isotopes of nitrogen ( N) and carbon ( C) were measured along with OCs in ringed seals collected from the east and west sides of the Northwater Pol5mya by Fisk etal. [120]. Seals from these two locations were allowed to feed at the same trophic level, based on values in muscle, but had slightly different sources of carbon, based on measurements in muscle. After removal of... 

Koppen et al. [131] determined HBCD enantiomers in fish samples obtained from fish farms in Etnefjorden, Norway. Levels of HBCDs were detectable in the fish, and the enantiomeric ratios were observed to differ among different fish species. Several recent reports describe the measurement of HBCD enantiomers in marine mammals [122], fish [130,131], human serum[132], and, marine sediment [133]. In certain cases where non-racemic enantiomeric fractions were observed, biotransformations have been attributed to cytochrome P450 metabolism. 

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