Methylamine-modified graphene-based solid phase extraction combined with UPLC-MS/MS for the analysis of neonicotinoid insecticides in sunflower seeds

In this paper, methylamine modified graphene (CH3NH-G) was synthesized and used as solid-phase extraction (SPE) sorbent to cleanup the acetonitrile extract of sunflower seeds for the determination of neonicotinoid insecticides by UPLC-MS/MS. The effects of the type of extraction solvent, pH, the amount of CH3NH-G sorbent as well as the type and volume of eluent on the extraction efficiency were evaluated. Good linearity was obtained for the analytes with coefficient of determination (R-2) in the range of 0.9986-0.9998. LOD (S/N=3) and LOQ (S/N=10) were below 6 and 20 ng kg(-1), respectively. Method recoveries were between 74.3% and 119.1%. Relative standard deviations (RSD) for eight replicate determinations were in the range of 1.7-2.9%. The proposed method has been applied to the analysis of 3 kinds of sunflower seed samples from local market.