Indirect Method for Simultaneous Determinations of 3-Chloro-1,2-Propanediol Fatty Acid Esters and Glycidyl Fatty Acid Esters

Recent concerns about potential health risks associated with 3-chloro-1,2-propanediol fatty acid esters (3-MCPD esters) and glycidyl fatty acid esters (GEs) in refined vegetable oils and fats have led to development of various methods for quantitative determinations of these compounds. Among them, indirect methods, which determine total amount of 3-MCPD and glycidol after hydrolysis of the esters, have an advantage over direct methods, which require a reference standard for each of the many possible species of fatty acid esters to be quantified. The existing indirect methods, however, may yield unreliable results or require long hours of alkaline methanolysis. To overcome these shortcomings, the objective of this study was to develop a reliable and rapid indirect method for simultaneous determinations of 3-MCPD esters and GEs. By using Candida rugosa lipase and sodium bromide for a hydrolysis/bromination step, 3-MCPD esters and GEs were transformed within 30 min to 3-MCPD and 3-bromo-1,2-propanediol (3-MBPD), respectively, without interconversion. Gas chromatography-mass spectrometry (GC-MS) analysis of 3-MCPD and 3-MBPD derivatized with phenylboronic acid showed 89-108 % recovery of 3-MCPD-diesters, -monoesters, and GEs from various oils and fats spiked at 2 and 20 mg/kg. The method should be useful for routine analysis of 3-MCPD esters and GEs.