Determination of six amide pesticide residues in vegetables and fruits by solid phase extraction-ultra high performance liquid chromatography-tandem mass spectrometry

A solid phase extraction coupled with ultra high performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) method was developed for simultaneous determination of six amide pesticides, cyantraniliprole, mandipropamid, boscalid, fluopicolide, thifluzamide and flubendiamide, in vegetables and fruits. After extraction with acetonitrile, purification with Florisil SPE cartridges and dissolution with methanol, the targets in the sample solutions were analyzed by UPLC-MS/MS on an Agilent Proshell 120 EC-C18 column with a mixture of 0.1% formic acid solution and methanol as the mobile phases under gradient elution conditions. The mass spectrometer operated in multiple reaction monitoring (MRM) mode with the negative and positive modes. Good linearity was obtained for the six amide pesticides at the mass concentrations of 0.000 5 - 1.00 mg/L with the correlation coefficients more than 0.999. The fortified recoveries were in the range of 72.4% - 119.4% with the concentration levels at 0.01, 0.1 and 1.0 mg/kg for cyantraniliprole, mandipropamid, boscalid, fluopicolide, thifluzamide, and 0.001, 0.01 and 0.1 mg/kg for flubendiamide. The relative standard deviations (RSDs) were less than 15% and the limits of quantification were 0.01 mg/kg for cyantraniliprole, mandipropamid, boscalid, fluopicolide, thifluzamide, and 0.001 mg/kg for flubendiamide. All the above observations indicate that the established analytical method is simple, efficient and sensitive, and suitable for the determination of the six amide pesticides in vegetables and fruits.