Gas Chromatography/Electron-Capture Negative Ion Mass Spectrometry for the Quantitative Determination of 2- and 3-Hydroxy Fatty Acids in Bovine Milk Fat
- 21 June 2008
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of Agricultural and Food Chemistry
- Vol. 56 (14), 5500-5505
- https://doi.org/10.1021/jf800647w
Abstract
2- and 3-hydroxy fatty acids (2- and 3-OH-FAs) are bioactive substances reported in sphingolipids and bacteria. Little is known of their occurrence in food. For this reason, a method suitable for the determination of OH-FAs at trace levels in bovine milk fat was developed. OH-FAs (and conventional fatty acids in samples) were converted into methyl esters and the hydroxyl group was derivatized with pentafluorobenzoyl (PFBO) chloride to give PFBO- O-FA methyl esters. These derivatives with strong electron affinity were determined by gas chromatography interfaced to mass spectrometry using electron-capture negative ion in the selected ion monitoring mode (GC/ECNI-MS-SIM). This method proved to be highly sensitive and selective for PFBO-O-FA methyl esters. For the analysis of samples, two internal standards were used. For this purpose, 9,10-dideutero-2-OH-18:0 methyl ester (ISTD-1) from 2-OH-18:1(9 c) methyl ester as well as the ethyl ester of 3-PFBO-O-12:0 (ISTD-2) was synthesized. ISTD-1 served as a recovery standard whereas ISTD-2 was used for GC/MS measurements. The whole-sample cleanup consisted of accelerated solvent extraction of dry bovine milk, addition of ISTD 1, saponification, conversion of fatty acids into methyl esters by use of boron trifluoride, separation of the methyl esters of OH-FAs from nonsubstituted FAs on activated silica, conversion of OH-FAs methyl esters into PFBO-O-FA methyl esters, addition of ISTD-2, and measurement by GC/ECNI-MS-SIM. By this method, ten OH-FAs were quantified in bovine milk fat with high precision in the range from 0.02 +/- 0.00 to 4.49 +/- 0.29 mg/100 g of milk fat.This publication has 20 references indexed in Scilit:
- Highly selective and sensitive gas chromatography–electron-capture negative-ion mass spectrometry method for the indirect enantioselective identification of 2- and 3-hydroxy fatty acids in food and biological samplesJournal of Chromatography A, 2007
- A Gas Chromatography/Electron Ionization−Mass Spectrometry−Selected Ion Monitoring Method for Determining the Fatty Acid Pattern in Food after Formation of Fatty Acid Methyl EstersJournal of Agricultural and Food Chemistry, 2005
- 3-Hydroxy fatty acids in saliva as diagnostic markers in chronic periodontitisJournal of Microbiological Methods, 2005
- The 3-hydroxy fatty acids as biomarkers for quantification and characterization of endotoxins and Gram-negative bacteria in atmospheric aerosols in Hong KongAtmospheric Environment, 2004
- Fatty acid and 3‐hydroxy fatty acid composition of two Hypericum species from TurkeyEuropean Journal of Lipid Science and Technology, 2004
- Hydroxy fatty acids in marine dissolved organic matter as indicators of bacterial membrane materialOrganic Geochemistry, 2003
- Gas chromatographic and mass spectrometric methods for the characterisation of long-chain fatty acids: Application to wool wax extractsAnalytica Chimica Acta, 2002
- Gas–liquid chromatography–mass spectrometry of hydroxy fatty acids as their methyl esters tert.-butyldimethylsilyl ethersJournal of Chromatography A, 1998
- Gas chromatography-mass spectrometry methods for analysis of 2- and 3-hydroxylated fatty acids: Application for endotoxin measurementJournal of Microbiological Methods, 1993
- Gas chromatography-mass spectrometry of lipopolysaccharide 3-hydroxy fatty acids: comparison of pentafluorobenzoyl and trimethylsilyl methyl ester derivativesJournal of Chromatography A, 1992