Dissipation, Residue, and Dietary Risk Assessment of Methoxyfenozide, Chlorantraniliprole, Indoxacarb, Lufenuron, and Chlorfenapyr in Spinach Using a Modified QuEChERS Method Combined with a Tandem Mass Spectrometry Technique

Spinach is a frequently consumed vegetable worldwide. Chemical pesticides are widely used to produce spinach with high yield and quality. However, the unregulated use of pesticides negatively impacts human and environmental health. A simple and efficient method using dispersive solid-phase extraction (d-SPE) combined with field experiments was conducted to study the residue dissipation of methoxyfenozide, chlorantraniliprole, indoxacarb, lufenuron, and chlorfenapyr in spinach under different planting conditions. The results showed that the half-lives of methoxyfenozide, chlorantraniliprole, indoxacarb, lufenuron, and chlorfenapyr in spinach were 1.1-3.0 d, 2.6-4.0 d, 1.7-4.2 d, 3.4-4.4 d, and 2.8-4.3 d, respectively. The five pesticides rapidly degraded without significant differences between the open and greenhouse fields. The final residue of indoxacarb in spinach was not higher than the maximum residue limit (MRL) in China (3 mg kg(-1)); the highest residual value was 1.0 mg kg(-1). Although the MRLs of methoxyfenozide, chlorfenapyr, and lufenuron for spinach are yet to be formulated in China, the long-term dietary risk for the four pesticides was acceptable, with an RQ < 100%, according to the international and national assessments. These results are necessary to provide guidance for the proper and safe use of these pesticides.