LC-MS/MS Determination of 40 Pesticide Residues in Garlic

LC-MS/MS was applied to simultaneous determination of residual amounts of 40 pesticides in garlic. The sample was extracted with H3PO4-acidified acetonitrile and then purified by QuEChERS method. The purified solution was separated on Waters HSS T3 C18 chromatographic column, using a mixture of methanol and HCOOH-NH4OH (0.01+0.05+99.94) solution as mobile phase in the gradient elution. ESI and MRM were adopted in MS. Linear relationships were found between values of peak areas and mass concentrations of the 40 pesticides in the same range of 5.0-400 μg·L-1, with lower limits of determinaiton (10S/N) in the range of 0.1-5 μg·kg-1. Values of recovery obtained by standard addition method were in the range of 70.1%-129%, and RSDs found (n=5) were in the range of 0.6%-9.3%.