Determination of total 3-chloropropane-1,2-diol (3-MCPD) in edible oils by cleavage of MCPD esters with sodium methoxide

A method for the determination of total 3-chloropropane-1,2-diol (3-MCPD) in edible fats and oils was presented. 3-MCPD was released from 3-MCPD fatty acid esters by transesterification with NaOCH3/methanol. After derivatization with phenylboronic acid, 3-MCPD was determined by GC-MS. Deuterium-labeled 3-MCPD was used as internal standard. In a model experiment, it was shown that acidic hydrolysis with methanol/sulfuric acid, which is normally used for the release of 3-MCPD from its esters, can cause problems because under acidic conditions additional 3-MCPD can be formed. No additional 3-MCPD was formed using NaOCH3/methanol for transesterification. Eleven samples of cold-pressed and refined safflower oils were analyzed with this method. Levels of total 3-MCPD were in the range from < 100 up to 3200 mu g/kg.