Identification and Quantification of Urinary Metabolites From Short Term Exposure to Acrylamide

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SAB3-PD-02 Introduction: It is known that heat treated carbohydrate rich foods may contain high levels of acrylamide (AA), and concentrations up to 4000 μg/kg in potato crisps and 2000 μg/kg in french fries have been reported. In order to get more information on human exposure to AA and its metabolism, a method for determination of known urinary metabolites from dietary exposure to AA has been developed, utilizing solid phase extraction and liquid chromatography with positive electrospray MS/MS detection. Methods: The urinary metabolites were synthesized and their structures were determined by NMR and MS. To test the method, a pilot study was conducted, in which all urine from 6 volunteers (1 smoker) was collected during 48 hours starting with 24-hour fasting. The chromatography was performed on a graphitized (Hypercarb) column with dimensions 2.1 × 50 mm and 5-μm particles size. For detection, a triple quadrupole mass spectrometer operated in multiple reaction monitoring mode was used. Results: The assay was validated in the range from 8.6 μg/L to 342.9 μg/L. The 2 urinary metabolites, N-acetyl-S-(3-amino-2-hydroxy-3-oxopropyl)cysteine (MA-GA3) and N-acetyl-S-(3-amino-3-oxopropyl)cysteine (MA-AA), were found above the detection limit. Fasting during 1 day caused about a 50% decrease in the total level of the metabolites. However, after 1 day of a normal diet, the urinary metabolite levels had returned to prefasting levels. The total amount of acrylamide excreted over the period acrylamide in the form of urinary metabolites was estimated to be about 40 μg AA per day for the average nonsmoker. Discussion and Conclusions: The urinary metabolites were baseline separated on HPLC, and the use of tandem mass spectrometry resulted in high selectivity and sensitivity. The significance of fasting on the reduction of the urinary metabolites makes it plausible that the major part of the AA, excreted as urinary metabolites, originates from the diet. It has been demonstrated that the method has potential for biomonitoring the short-term exposure to acrylamide in humans.