GC-MS/MS Determination of Residual Amounts of 41 Pesticides in Dendrobium Candidum with Dispersive Solid Phase Extraction

The dendrobium candidum sample soaked with appropriate amount water was extracted ultrasonically with acetonitrile accompanied by high speed vortex. After centrifugation, the supernatant was purified with dispersive solid phase extraction. C₁₈ and PSA were used as adsorbents. GC-MS/MS was applied to the determination of residual amounts of 41 pesticides in purified liquid with dispersive solid phase extraction. Agilent VF-5MS chromatographic column was used for GC separation and the multiple reaction monitoring mode was adopted in MS/MS determination. cis-Heptachlor epoxide was used as internal standard. Detection limits (3S/N) of the 41 pesticides were in the range of 0.001-0.024 mg·kg^-1. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 75.1%-115%, with RSDs (n=6) of determined values in the range of 0.40%-11%.