Optimization of matrix solid phase dispersion coupled with gas chromatography electron capture detection for determination of chlorinated pesticides in soil.

A fast, simple and efficient technique based on matrix solid phase dispersion has been presented for extraction and clean-up of some chlorinated pesticides and derivative products; α-BHC, β-BHC, γ-BHC, δ-BHC, heptachlor, aldrin, dieldrin, endrin, endosulfan 1, endosulfan 2, 4,4'-DDT, 4,4'-DDE, 4,4'-DDD, heptachlor epoxide, endrin aldehyde, endosulfan sulfate. Box-Behnken response surface methodology was employed for optimization of the extraction efficiency. As the optimized procedure, 0.5 g of dried and sieved soil samples were mixed with 2.0 g of 10% C18 in silica (w/w) as dispersant and after transferring into the extraction tube they were extracted with 8 mL of dichloromethane-n-hexane (1:1, v/v). Gas chromatography with electron capture detector was used for selective and sensitive determination of the analytes. Recoveries for the extraction of the proposed analytes were calculated and were satisfying (more than 75%), except for endrin aldehyde (59%) and endosulfan sulfate (62%). Also the method was linear over the calibration range (R(2)>0.991) and the quantitative results were reasonably reproducible and sensitive (LODs ranged between 0.3 and 1.8 ng g(-1)).