Determination of residual dynamics and final residues of pyraclostrobin in the ginseng root, stem, leaf and soil by HPLC-MS/MS

【Objective】To identify the residual dynamics and final residues of pyraclostrobin 250 g·L^-1 EC in the ginseng root, stem, leaf and soil after spraying during the ginseng growth period.【Method】The samples were extracted with acetone, cleaned up with primary secondary amine (PSA) solid phase extraction cartridge, and determined by high performance liquid chromatography coupled with electrospray mass spectrometry (HPLC-MS/MS).【Result and conclusion】The half lives of pyraclostrobin were from 6.35 to 8.75 d in the ginseng root, stem, leaf and soil with a spraying dosage of 666.67 g·hm^-2. Final residues of pyraclostrobin in the ginseng root, stem, leaf and soil were below 0.020 6 mg·kg^-1 over 60 d at a spraying dosage ranging from 333.33 to 666.67 g·hm^-2. It is recommended that the preharvest interval of pyraclostrobin 250 g·L^-1 EC should be set 35 d and sprayed one time at the dosage of no more than 666.67 g·hm^-2.