Optimization of QuEChERS sample preparation method for acrylamide level determination in coffee and coffee substitutes

Modification of QuEChERS sample preparation method for the determination of acrylamide (2-propeneamide, AA) in coffee (roasted and instant) and coffee substitutes via silylation has been reported. The AA level after conversion to N,O-bis-(trimethylsilyl)acrylamide (BTMSA) was determined with gas chromatography/ion-trap mass spectrometry in a single ion monitoring mode (GC-SIM-MS). A sample of instant coffee was used to develop an analytical method in the optimisation experiment, which involved the selection of the most suitable sorbents for the dispersive solid phase extraction (d-SPE) clean-up. The usefulness of the method has been verified based on the recovery ratio of acrylamide (fortified samples analysis). Seven variants of the method were tested. The obtained results showed that the best recovery of 95% was obtained using a combination of PSA and SAX sorbents with the addition of hexane in the initial step of extraction. The chosen method was applied for the AA determination in 17 roasted, 10 instant and 8 coffee substitutes samples. The results of acrylamide content ranged from 17.7 ± 1.4 to 776.1 ± 8.8 μg kg− 1 in roasted coffee, from 96.4 ± 1.7 to 346.5 ± 10.9 μg kg− 1 in the case of instant coffee, and finally from 70.0 ± 6.0 to 188.9 ± 0.1 μg kg− 1 in the samples of coffee substitutes. The obtained results are in good agreement with previous literature reports.