Determination of polycyclic aromatic sulfur heterocycles in fossil fuel-related samples.

An analytical method is described for the separation, identification, and quantification of a number of polycyclic aromatic sulfur heterocycles (PASHs) in three fossil fuel-related samples including two Standard Reference Materials (SRMs), SRM 1597 (coal tar) and SRM 1582 (petroleum crude oil), and a decant oil. The compounds measured include the 3 possible naphtho[b]thiophenes; dibenzothiophene and selected methyl-, ethyl-, dimethyl-, and trimethyl-substituted isomers; the 3 possible benzo[b]naphthothiophenes; and the 30 methylbenzo[b]naphthothiophenes isomers. Because of the occurrence of polycyclic aromatic hydrocarbons and PASHs together with their large number of possible alkyl-substituted isomers, the analytical method described requires a number of prerequisites: effective sample cleanup, selective stationary phases, and selective methods of detection. The sample cleanup involves solid-phase extraction using aminopropylsilane cartridges with different solvent mixtures followed by normal-phase liquid chromatographic isolation of the PASHs based on the number of aromatic carbons. These aromatic ring fractions are then separated by capillary gas chromatography using two stationary phases with different selectivities, 5% phenyl-substituted methylpolysiloxane stationary phase and 50% phenyl-substituted methylpolysiloxane stationary phase, and analyzed with mass-selective detection and atomic emission detection. A liquid crystalline stationary phase was also used to separate the methylbenzo[b]naphthothiophene isomers in the crude oil sample. Advantages and limitations of each chromatographic and detection technique are discussed.

Marine mammals as global pollution indicators for organochlorines.

Blubber tissues of the following marine mammals differing in their geographic distribution (North Atlantic, North Pacific, Bering Sea/Arctic Ocean), trophic level, and feeding habits were analyzed for their organochlorine contents: two seal species (harbor seals--Phoca vitulina, northern fur seals--Callorhinus ursinus), three toothed whale species (belukha whales--Delphinapterus leucas, one common dolphin--Delphinus delphis, one pilot whale--Globicephala melaena), and one baleen whale species (a bowhead whale--Balaena mysticetus). As xenobiotics were quantified the seven indicator congeners of the polychlorinated biphenyls (PCB 28, 52, 101, 118, 138, 153, and 180), three isomers of the hexachlorocyclohexanes (alpha-, beta- and gamma-HCH) as well as six components of the DDT-group (4,4'-DDT, 4,4'-DDD, 4,4'-DDE, 2,4'-DDT, 2,4'-DDD, and 2,4'-DDE). When comparing the xenobiotic levels of these marine mammals, it showed that the animals from the western North Atlantic were contaminated about 15 times more with organochlorines than the animals from the eastern North Pacific and the Bering Sea/Arctic Ocean. The total organochlorine burden, the 4,4'-DDE-percentage as well as the metabolic PCB patterns correlate with the trophic levels of the marine mammals studied. The quantitative analyses were done by high-resolution capillary gas chromatography with electron capture detection (HRGC/ECD) whereas the analyses of the metabolic PCB patterns were done by high-resolution capillary gas chromatography and mass selective detection (HRGC/MSD).

Interlaboratory comparison study for PCB congeners and chlorinated pesticides in beluga whale blubber.

Three laboratories participated in an interlaboratory comparison exercise for the determination of polychlorinated biphenyl (PCB) congeners and chlorinated pesticides in Standard Reference Material (SRM) 1588 (Organics in Cod Liver Oil) a whale blubber control material, and six beluga whale (Delphinapterus leucas) blubber samples. The results are generally in good agreement. The minor disagreement of some of the results may be attributed to differences in detector calibrations, differences in chromatographic separation selectivity for specific compounds, or both. The SRM and control material help to validate the analytical procedures and to verify that these procedures remain in control.