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Licentiate thesis, 2000

Characterisation of chlorinated fatty acid metabolites in human cells after uptake of dichlorostearic acid, as determined by a halogenspecific detector (XSD)

Åkesson-Nilsson, Gunilla

Abstract

Chlorinated fatty acids (CIFAs) have been found to account for a considerable portion of the extractable organically bo und chlorine in aquatic animals. Methods particularly suitable for the determination of CIFAs have relatively newly been developed, which may explain why these compounds did not come to attention as a potentially hazardous environmental pollutant until during the recent decade. The presence of CIFAs in human tissues has not yet been reported, and it is not known if human cells can incorporate and metabolise these compounds. Recently a new halogen specific detector (XSD) has been introduced. It is described to be a sensitive, selective, and robust detector in the determination of halogenated pesticides. It has been declared to be more stable and easier to maintain than other halogen selective detectors. The XSD operates in an oxidative pyrolysis mode and the sample compounds are converted into their oxidation products. When halogen-containing compounds enter the hot detector, the detector current will increase. CIF As have not earlier been studied by an XSD. The aim of this work was to study i) the XSD, connected to a gas chromatograph, in the determination of CIFA methyl esters (CIFAMEs), and ii) the incorporation and metabolism of CIFAs in human cell lines, as determined by XSD detection. It was shown that the XSD provides a detection limit (0.2 ng of dichlorostearic acid methyl ester) and a selectivity ((response CIFAMEs)/(response unchlorinated fally acid methyl esters)) >> 10⁴ similar to that of the electrolytic conductivity detector (ELCD), commonly used in determination of CIFAMEs. Furthermore, the XSD was found to be very easy and stable to maintain in the analysis of CIFAMEs. In the determination of CIFAs obtained from human cell lines, it was established that human cells can incorporate dichlorostearic acid and degrade it to dichloropalmitic acid and dichloromyristic acid, probably through α3-oxidation. CIFAs were found both in the neutrallipid and in the phospholipid fraction of the cultured cells. Dichloromyristic acid was the shortest CIFAs detected and was found to be released to the culture medium to a higher extent than the other CIFAs. The XSD was found to be a good alternative to the ELCD in the determination of CIFAs and the XSD is suitable for use in continued studies of the turnover of CIFAs in human cells.

Keywords

halogenated fatty acids; halogen-selective detection; phospholipids; neutral lipids; dichloropalmitic acid; dichloromyristic acid; beta-oxidation

Published in

Rapport / Sveriges lantbruksuniversitet, Miljöanalys
2000, number: 2000:9
Publisher: Department of Environmental Assessment, Swedish University of Agricultural Sciences

Authors' information

Åkesson-Nilsson, Gunilla
Swedish University of Agricultural Sciences, Department of Environmental Assessment

UKÄ Subject classification

Organic Chemistry

URI (permanent link to this page)

https://res.slu.se/id/publ/54422