Residues behavior and dietary exposure risk assessment of cyazofamid and its main metabolite CCIM in tomato and grape

The residue and dissipation dynamics of cyazofamid and its main metabolite 4-chloro-5-p-tolylimidazole-2-carbonitrile (CCIM) in tomato and grape were investigated by QuEChERS-high performance liquid chromatography-tandem mass spectrometry (QuEChERS-HPLC-MS/MS) method. Field experiments were conducted in ten sites for one year. And the dietary intake risk of cyazofamid was assessed. At three levels of 0.005 to 2 mg/kg (tomato) or 0.005 to 1 mg/kg (grape), the results showed that the average recoveries of cyazofamid and CCIM in tomato and grape were 86%-105% and 84%-105%, respectively, with RSD less than 10%. The quantitative limits (LOQ) for tomato and grape samples were both 0.005 mg/kg, which met the requirement of max residue limit of cyazofamid. The dissipation dynamics of cyazofamid in tomato and grape matrices fitted the first order kinetic equation, and the half-lives in tomato and grape were 4.9-10.3 d and 8.6-11.9 d, respectively. The dietary intake risk assessment indicated that the dietary exposure risk index of cyazofamid in tomato and grape fruits were less than 100%, which indicated that the dietary exposure risk was at an acceptable level. The level of pesticide exposure was different for different age and gender groups. In general, dietary exposure gradually decreased with the increase of age. Among them, children (2-4 years old) had the highest dietary exposure, and females in the same age groups had slightly higher dietary exposure than men.