Analytical method of solids for residual organochlorine pesticides with supercritical fluid extraction

Abstract

The authors have developed an analytical method for 13 residual organochlorine pesticides (Aldrin, Dieldrin, Endrin, Heptachlor, Heptachlor epoxide, α-BHC, β -BHC, γ-BHC, δ -BHC, o,p'-DDT, p,p'-DDD, p,p'-DDE and p,p'-DDT) in soil by CO2 supercritical fluid extraction (SFE). 1-Hexanesulfonic acid sodium salt was used as a modifier on SFE in this experiment. The recovery from 81 to 103% under condition where 2 mL of water was added to 2 g of spiked air-dried soil. The extraction efficiency was equivalent to that obtained by Soxhlet extraction. Furthermore, the soil contaminated with Dieldrin and p,p '-DDT was extracted by SFE and Soxhlet extractions so as to validate our SFE method. The result revealed that the recovery rates obtained by SFE were from 100 to 105% of those obtained by Soxhlet. This method has such advantages as simple operation, shorter extraction time (approximately 30 min) and less organic solvent required for extraction. These results suggest that our SFE method is effective to analyze residual organochlorine pesticides in soil. © 2009 The Japan Society for Analytical Chemistry.