A protocol for the measurement of bound 2-chloropropane-1,3-diol (2-CPD) and 3-chloropropane-1,2-diol 3-CPD) in foodstuffs using acid catalysed transesterification and GC/MS/MS has undergone single-laboratory validation. Validation of the method included an assessment of recovery (bias) of 3-CPD from reference 3-CPD mono- and diesters using a range of fortified and unfortified cereal, oil and potato products and participation in a EC proficiency test on 3-CPD-esters. Method repeatability was assessed by measuring bound 2- and 3-CPD present in a processed cereal product. The results indicated that the method was fit for purpose for the measurement of bound 2- and 3-CPD over concentration ranges of 40–10 000 µg/kg for oils, and 4–4000 µg/kg for foodstuffs depending on the fat content. The selectivity/robustness of the method was demonstrated by fortifying samples with ‘free’ 3-CPD, chloride ions, glycerol and glycidyl butyrate: the procedure was found to be selective for ‘bound’ 3-CPD and no adventitious formation of 2- or 3-CPD occurred during analysis.
Practical applications: This method provides a single-laboratory validation of a method to measure amounts of bound 2- and 3-CPD in a wide range food. The method provides the information necessary to assist researchers engaged in the selection and validation of analytical methods to measure these contaminants in foods.