A sensitive gas chromatographic–tandem mass spectrometric method for detection of alkylating agents in water: Application to acrylamide in drinking water, coffee and snuff

Abstract

A sensitive analytical method for the analysis of acrylamide and other electrophilic agents in water has been developed. The amino acid L-valine served as a nucleophilic trapping agent. The method was applied to the analysis of acrylamide in 0.2–1 mL samples of drinking water or Millipore-filtered water, brewed coffee, or water extracts of snuff. The reaction product, N-(2-carbamoylethyl)valine, was incubated with pentafluorophenyl isothiocyanate to give a pentafluorophenylthiohydantoin (PFPTH) derivative. This derivative was extracted with diethyl ether, separated from excess reagent and impurities by a simple extraction procedure, and analyzed by gas chromatography-tandem mass spectrometry. (²H₃)Acrylamide, added before the reaction with L-valine, was used as internal standard. Acrylamide and the related compound, N-methylolacrylamide, gave the same PFPTH derivative. The concentrations of acrylamides were ≤0.4 nmol L⁻¹ (≤0.03 µg acrylamide L⁻¹) in water, 200 to 350 nmol L⁻¹ in brewed coffee, and 10 to 34 nmol g⁻¹ snuff in portion bags, respectively. The precision (the coefficient of variation was 5%) and accuracy of the method were good. The detection limit was considerably lower than that of previously published methods for the analysis of acrylamide.