Improvement of Standard Method for Determination of Organochlorine Pesticide Residue in Tobacco

In order to increase the detectable number and test speed of organochlorine pesticide residue in tobacco, the standard method for determination of organochlorine pesticide residue in tobacco from ISO 4389:2000(GB/T 13596-2004) was improved. Soxhlet extraction and n-hexane (extracting solvent) were replaced by accelerated solvent extraction (ASE) and component solvent of w-hexane and acetone (1:1, v/v) f respectively, and extracting temperature was optimized. The residues of organochlorine pesticides in 65 domestic and imported tobacco samples were determined with the improved method and ISO 4389:2000 method, the results showed that:1) β -endosulfan was detected in 10 samples by the improved method, but not found by ISO 4389:2000; 2) the organochlorine pesticides detectable by both methods were almost the same except for β-endosulfan, quantitatively, their coefficients of variation were below the acceptable limits for trace pesticide determination of 20%; 3) no organochlorine pesticide was detectable in 17 samples t which accounted for 26.2% of total samples; 4) the detection rate of o, p' -DDT was the highest (up to 43. 1%), neither Dieldrin nor Endrin was detected in all samples;5) the numbers of detectable organochlorine pesticides were 47 and 43 in domestic and imported cigarette samples, respectively; organochlorine pesticides were detected in all of the imported samples, particularly α-endosulfan, β-endosulfan, and o, p'一DDT,while these pesti-cides were detectable only in 4 domestic samples; 6) the numbers of detectable pesticides in domestic leafsamples were slightly higher than that in imported samples, which happened mainly in a couple of domestic samples; 7) the residues of organochlorine pesticides in all samples were lower than CORESTA recommendedlimits. The improved method could replace ISO 4389:2000 in fast detection of the residues of organochlorinepesticides in tobacco samples.