Structural characterization of 5,6‐dichlorotetradecanoic acid, an isolated metabolite of 9,10‐dichlorooctadecanoic acid, by studying picolinyl esters, pyrrolidides and methyl esters with electron ionization mass spectrometry

Abstract

A method is presented for identification of positional isomers of dichlorinated fatty acids, based on derivatization to picolinyl esters prior to gas chromatographic/mass spectrometric analysis in the electron ionization mode. The mass spectra of the picolinyl esters showed structure-specific fragmentation patterns. By using the picolinyl ester, 5,6-dichlorotetradecanoic acid was identified as a metabolite from a cell-culture medium obtained by culturing human cell lines in media supplemented with threo-9,10-dichlorooctadecanoic acid. This indicates that dichlorinated fatty acids are degraded by beta-oxidation. It is also possible to locate tentatively the position of chlorine atoms in 5,6-dichlorotetradecanoic acid as its methyl ester or pyrrolidide.

Characterization and sources of extractable organochlorine in white sucker downstream from bleached kraft pulp mills

“…Analytical evidence for these -oxidative products was recently shown in our work on identification of chlorinated fatty acids in freshwater fish sampled downstream from bleached kraft pulp mills [19][20][21]. Thereafter, Å kesson-Nilsson and Wese´n identified 5,6-dichlorotetradecanoic acid as a metabolite of 9,10-dichlorooctadecanoic acid in human cell lines, which also suggests -oxidation [22].…”

Preparation of Dimethyl Disulfide Adducts from the Mono‐Trans Octadecadienoic Acid Methyl Esters

“…However, the double‐bond positions cannot be determined by comparing the similarity between the mass spectrum and the library data. Conventionally, the derivatives such as pyrrolidide or picolinyl ester are used in determining the double‐bond positions of unsaturated fatty acid with GC/MS (Åkesson‐Nilsson & Wesén, ; Andersson, Heimermann, & Holman, ; Andersson & Holman, ; Christie, , ; Christie, Brechany, & Holman, ; Christie & Han, ; Destaillats & Angers, ; Dobson & Christie, ; Dubois, Barnathan, Gouygou, & Bergé, ; Dubois, Barthomeuf, & Bergé, ; Wretensjö, Svensson, & Christie, ). With the aforementioned method, the double‐bond positions can be determined by the difference of fragment ions in which cleavage occurs between the double‐bond carbons is 12u, and the difference of fragment ions in which cleavage occurs between the single‐bond carbons is 14u.…”