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.