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 (R2) in the range of 0.9986-0.9998. LOD (S/N=3) and LOQ (S/N=10) were below 6 and 20ngkg-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.