Multiresidue analysis of 18 organochlorine pesticides in traditional chinese medicine.

A simple and efficient method for simultaneous gas chromatographic (GC) determination of 18 organochlorine pesticides [tecnazene, hexachlorobenzene, alpha-benzenehexachloride (BHC), pentachloronitrobenzene (PCNB), gamma-BHC, heptachlor, aldrin, methyl pentachlorophenyl sulfide, beta-BHC, delta-BHC, heptachlor epoxide, alpha-endosulfan, trans-chlorodane, cis-chlorodane, p,p'-dichlorodiphenyl dichloroethylene, o,p'-DDT, p,p'-DDD, and p,p'-DDT] in Traditional Chinese Medicine (TCM) is described. The procedure involves ultrasonic extraction and sulphuric acid treatment as the cleanup method. Detection of the sample is performed by GC-electron capture detection. A series of experiments are conducted to optimize the final pretreatment conditions [acetone-petroleum ether (1:1) as the extract solvent, ultrasonication for 15 min, three steps, concentrated sulphuric acid with 10% water for sulphuric acid treatment]. Recovery studies are performed at 10, 50, and 100 parts-per-billion (ppb) fortification levels of each organochlorine pesticide, except for alpha-endosulfan, which are 20, 100, and 200 ppb. The percentage recoveries range from 77.9% +/- 6.4% to 114.0% +/- 8.1% (average +/- standard deviation). The simple and rapid method may be used to routinely determine organochlorine pesticides in TCM.