A New LC/MS-Method for the Quantitation of Acrylamide Based on a Stable Isotope Dilution Assay and Derivatization with 2-Mercaptobenzoic Acid. Comparison with Two GC/MS Methods

Acrylamide (AA) was found to form a stable thioether in reasonable yields (45-50%) when reacted with 2-mercaptobenzoic acid at 20 °C for 3 h. On the basis of this finding and using [¹³C₃]-acrylamide as the internal standard, a sensitive and selective new stable isotope dilution analysis for AA quantitation in food samples was developed based on single stage LC/MS. Comparison of the quantitative results obtained by applying the new method to potato chips, crispbread or butter cookies with data obtained by two stable isotope dilution analysis, using direct measurement of AA by GC/ MS, but differing in the workup procedure, revealed detection limits in the same order of magnitude (6.6 μg/kg). Quantitative data obtained by application of the three methods on the same samples of potato chips or cookies, respectively, were also in very good agreement. Quantitation of AA in crispbreads treated with an amylase/protease mixture did not show increased AA levels, thereby indicating that inclusion of AA in starch/protein gels is not very probable during breadmaking.