GC-MS Determination of Residual Amounts of 118 Pesticides in Grape Wine with SPE Pretreatment

Residual amounts of 118 pesticides in sample (10 g) of grape wine were extracted with 20 mL and 15 mL of acetonitrile in succession, centrifuged and the supernatants were collected. After evaporation to dryness at 40 ℃ in a rotary evaporator, the residue was dissolved in 5 mL of a mixture of acetonitrile and toluene (3+1). The solution was purified on the Carb/PSA double layer SPE column. The eluate obtained was evaporated to near dryness. The residue was taken up with 1.0 mL of a mixture of acetone and n-hexane (1+1), and the solution was used for GC-MS analysis, with HP-5MS capillary chromatographic column, and EI as well as SIM in MS determination. An external standard was used for quantitative analysis. Values of lower limit of determination (10S/N) found were ranged from 0.010 to 0.031 mg·kg-1 and values of recovery found by standard addition method were in the range of 67%-124% with RSD′s (n=5) less than 12.2%.