Residue determination by SPE-HPLC-MS/MS and risk assessment of flusilazole in the ginseng and soil

【Objective】 To investigate flusilazole residues in ginseng and to conduct risk assessment. 【Method】 A solid phase extraction (SPE) and high performance liquid chromatography coupled with mass spectrometry (SPE-HPLC-MS/MS) method was developed to determine the residual dissipation and final residues of flusilazole 400 g·L^-1 EC in ginseng root and soil at Fusong County and Ji’an City in 2011 and 2012. The dietary risk assessment was also conducted using the calculation of risk quotient (RQ).【Result and conclusion】 The half-lives of flusilazole were 7.85-9.94 d in root and 5.59-7.13 d in soil at spraying dosage of 90 g·hm^-2. Final residues of flusilazole were below 0.043 3 mg·kg^-1 in root and below 0.037 5 mg·kg^-1 in soil, and the risk was very low with 4.59×10^-5 (much less than 1) of a risk quotient, and the residues could be declined to the safe level over 35 days after spraying once or twice at a dosage ranging from 60 to 90 g·hm^-2. It is recommended that the MRL of flusilazole in ginseng should be 0.05 mg·kg^-1 temporarily, and its preharvest interval should be set at 35 days.