Chlorinated triacylglycerols in fish lipids? Chromatographic and mass spectrometric studies of model compounds

✍ Scribed by P. Sundin; P. Larsson; C. Wesén; G. Odham

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 737 KB
• Volume: 21
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/bms.1200211204

✦ Synopsis

Triacylglycerols containing chlorinated fatty acids are tentative components in fish lipids. The determination of relevant model compounds was therefore examined with high-performance liquid chromatography (HPLC) and HPLC/mass spectrometry, and with gas chromatography and gas chromatography/mass spectrometry after releasing the fatty acid moieties. In reversed-phase HPLC, the retention of triacylglycerols containing chlorinated octadecanoic acids decreased with increasing numbers of chlorine atoms. Plasma spray ionization mass spectrometry of the chlorinated triacylglycerols produced abundant chlorinated fragments, but the sensitivity was low. The gas chromatography detection limits of chlorooctadecanoic acid methyl esters were about 1 ng with flame ionization detection and about 0.5 ng with electron capture detection, at a signal-to-noise ratio of 3:l. Electron impact ionization of the methyl esters caused extensive loss of HCI, limiting its value in quantitative determination. Ammonia positive ion chemical ionization mass spectrometry of the chlorooctadecanoic acid methyl esters, and isobutane negative ion chemical ionization mass spectrometry of the pentafluorobenzyl esters, produced spectra with abundant molecular weight-related ions. Detection limits were about 0.1 ng in the selected ion monitoring mode. Acid and base-catalysed hydrolysis and transesterification liberated 100%, and enzymecatalysed hydrolysis 80%, of free acids or methyl esters from tri-9,1bdichlorooctadecanoyIglycerol. Only basecatalysed hydrolysis led to a loss of chlorine, of about 5%, from the released units.