Problems and Solutions in Pesticide Analysis Using Solid-phase Extraction (SPE) and Gas Chromatography Ion-trap Mass Spectrometry Detection (GC-MS)

Abstract

In the present study an analytical method was tested for the determination of selected pesticides and metabolites using solid-phase extraction (SPE) and gas chromatography ion-trap mass spectrometry (GC-MS). The extraction efficiency of C18, Isolut ENV+, and Lichrolut EN for SPE was compared for trifluralin, fenitrothion, endosulfan, propargite, 2,4-D, 3-methyl-4-nitrophenol, 2-(4-tert-butylphenoxy)cyclohexanol, endosulfan sulfate, and 2,4-dichlorophenol. Isolut ENV+ and C18 showed good results as sorbents and acetone as an elution solvent for SPE for the selected pesticides. Recoveries varied between 36% and 176% with a relative standard deviation of 2...18%. Because of coextracts from the SPE materials, recovery values higher than 100% were obtained for fenitrothion, endosulfan sulfate, and 2,4-D with C18 as well as for endosulfan sulfate and 3-methyl-4-nitrophenol with Isolut ENV+. A standard addition method was used to verify the occurrence of coextracts in the sample after SPE.