Magnetic graphene oxide as a convenient nanosorbent to streamline matrix solid-phase dispersion towards the extraction of pesticides from vegetables and their determination by GC-MS

This study describes the employment of magnetic graphene oxide under the principle of matrix solid-phase dispersion, as a convenient and streamlined variant of the procedure for the development of an analytical method towards the extraction and determination of pesticides from vegetables. The properties of the magnetic graphene oxide make feasible the magnetic separation of the sorbent, directly after the blending step. This negates the need for additional steps commonly employed in the classical matrix solid-phase dispersion procedure, thus, resulting in a simpler sample preparation procedure. The excellent sorption properties of the nanosorbent were reaped to extract 45 multi-class pesticides from vegetables (cabbage, leek, and radicchio), prior to their separation and detection by gas chromatography-mass spectrometry. The hydrophilic nature of the sorbent allows the efficient blending with high-water content vegetables and, as a consequence, excellent recoveries of the pesticides (89-106% from all three examined vegetables), accompanied by good precision (relative standard deviation: 5.1-8.5%), are achieved. The limits of quantification are nearly 10 times lower (0.4-4.0 mu g kg(-1)) than the maximum residue limit established by the European Council (i.e. 10 mu g kg(-1)). All of the above, along with the negligible interference from matrix components bestow excellent merits on the developed analytical method, which can be exploited for the routine analysis of pesticides in relevant matrices.