Determination of tocopherols and tocotrienols in cereals and nuts by dispersive solid-phase microextraction-gas chromatography-mass spectrometry†
A modified sensitive, rapid and effective method based on ultrasound-assisted dispersive solid-phase microextraction (dSPME) was developed for the determination of tocopherols and tocotrienols in food samples. In this study, multi-walled carbon nanotubes (MWCNTs) were first used as a dSPME material for the pretreatment of vitamin E congeners. Several experimental parameters, including the extraction solvent, amount of sorbent, extraction time, and desorption conditions, were evaluated. Under optimal experimental conditions, good linearity was observed in the range of 0.01–40 μg mL−1 with correlation coefficients (r) > 0.998. The method was successfully applied to the analysis of tocopherols and tocotrienols in cereal and nut samples, and the recoveries of analytes obtained were in the range of 86.1–102.5%. The present method was compared with the classical saponification pretreatment. The results show that the proposed method was time-saving, convenient, sensitive and suitable for the determination of VE congeners in food samples.