Logische Datenstrukturen

Vetter, Max

doi:10.1007/978-3-322-80156-2_7

Cited by 1 publication

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“…ERs were rounded to five or zero for the second decimal digit. Five degrees of chlorination were monitored to ensure that no components were missed and to identify coeluting components that could result in artifacts (16). One sample of each species except striped mullet was fractionated on silica for elimination of possible coeluting organochlorine contaminants such as PCBs and for detection of lowabundant CTTs.…”

Section: Samplementioning

confidence: 99%

“…Second, enantiomer separations are typically performed isothermally to maximize chiral resolution (15). Lastly, coeluting components may alter the correct ER of target components even when the interferents have different SIM masses (16). Such artifacts may be avoided, however, by improvement of the chromatographic separation of the components either by MDGC (17) or liquid chromatographic fractionation prior to CSP-GC.…”

Section: Introductionmentioning

confidence: 99%

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Congener and Enantioselective Analysis of Toxaphene in Sediment and Food Web of a Contaminated Estuarine Wetland

Vetter

Maruya

2000

Environ. Sci. Technol.

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Enantioselective gas chromatography with electron capture negative ion mass spectrometry (GC/ECNI-MS) was employed to investigate the fate of toxaphene residues in contaminated sediment (source) and biota (receptor) representing several levels of an aquatic food web. Samples were collected from an estuarine marsh that was impacted by discharge from a former toxaphene plant. Several penta- to nonachlorobornanes were identified and enantiomerically resolved on a chiral stationary phase. Additional peak confirmation was obtained after fine fractionation of extracts on silica. Previously identified congeners including B6-923 (Hx-Sed), B7-515 (P-32), B7-1001 (Hp-Sed), B8-806/9 (P-42), B8-1412, B8-1413 (P-26), B8-2229 (P-44), B9-1679 (P-50), and B9-2206 (P-63) were detected, as were several unknown penta- and heptachlorobornanes. The majority of prominent congeners were essentially racemic in marsh sediment (maximum deviation 15%). In contrast, several congeners as well as several unknown hepta-CTTs were enantioselectively depleted in lower food web organisms; the enantiomer ratios (ERs) for B6-923 and B7-1001 in small fish (Fundulus sp.) were ∼2 and 0.6, respectively. These significant alterations of the ERs prove that even low-trophic level biota is able to degrade toxaphene components to some degree. In higher level predators, the ERs for B7-1001 were closer to racemic. Irrespective of trophic level, little or no shift in the ERs for B8-1413 (P-26) and B9-1679 (P-50), two recalcitrant chlorobornanes in mammals, relative to sediment were observed. These results indicate that biochemical transformations within the scope of the estuarine food web studied likely act to alter the residue pattern and the ultimate fate of toxaphene.

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Section: Samplementioning

confidence: 99%