A modified sample preparation for acrylamide determination in cocoa and coffee products

A modified sample preparation for acrylamide determination in difficult matrices such as cocoa and coffee by a liquid chromatography-tandem mass spectrometry method is presented in this work. For the sample pretreatment, different solvents, purification steps, and solid-phase extraction cartridges were evaluated. The analyses were carried out on a µ-Bondapak C18 column using acrylamide-D3 as internal standard. For identification and confirmation of acrylamide, relative retention time and two diagnostic ions were monitored. Good performance of the method was achieved by introducing a protein precipitation step with Carrez I and II solutions and a liquid-liquid extraction with ethyl acetate in combination with solid-phase extraction during the sample clean-up. A limit of detection of 10 µg/kg, a limit of quantitation of 20 µg/kg, mean recoveries ranging from 93 to 99%, coefficients of variation of 3.4% for repeatability, and from 1.7 to 10.8% for within-laboratory reproducibility were obtained during a laboratory validation procedure.