Determination of eight pesticides in Lycium barbarum by LC-MS/MS and dietary risk assessment

Abstract

A LC-MS/MS method for determination of eight pesticides (triadimefon, sulfoxaflor, flusilazole, tebuconazole, difenoconazole, amitraz, azoxystrobin, and thiophanate-methyl) in Lycium barbarum was established. The samples were extracted with acetonitrile, and then cleaned up by primary secondary amine. The extracts were diluted with 0.1% formic acid in water. The results showed that at the fortified levels of 0.01-10mg/kg, the average recoveries of these pesticides ranged from 82.1% to 96.2% with the relative standard deviations lower than 7%. The half-lives of eight pesticides were 1.3-5.0days in Lycium barbarum fruits. The pre-harvest interval of all pesticides mentioned above were investigated. Tebuconazole (14days), sulfoxaflor (14days) and flusilazole (28days) have longer pre-harvest interval than the others which have 7days. The dietary risks, assessed as hazard quotients, were far below 100%. The results showed that the eight pesticides applied to Lycium barbarum were comparably safe for the consumer.

Keywords: Amitraz (PubChem CID: 36324); Azoxystrobin (PubChem CID: 3034285); Carbendazim (PubChem CID: 25429); Dietary risk assessment; Difenoconazole (PubChem CID: 86173); Dissipation; Flusilazole (PubChem CID: 73675); Lycium barbarum; N-2,4-dimethylphenyl-N′-methylformamidine (PubChem CID: 36326); Pesticides; Sulfoxaflor (PubChem CID: 16723172); Tebuconazole (PubChem CID: 86102); Thiophanate-methyl (PubChem CID: 3032791); Triadimefon (PubChem CID: 39385).