Determination of Residues of Six 2,6-Dinitroaniline Pesticides in Tobacco

Abstract

In order to accelerate the detection of 2,6-dinitroaniline pesticide residues in tobacco,a method for determining the residues of 2,6-dinitroaniline pesticides,including flumetralin,pendimethalin,butralin,isopropalin,benfluralin and trifluralin,in tobacco and tobacco products by accelerate solvent extraction (ASE) with florisil and n-hexane as extracting solvent and gas chromatography with an electron capture detector using mirex as an internal standard was developed,and 100 samples of cigarette and tobacco leaf were tested.The results showed that:1) The recoveries of the pesticides ranged from 90.0% to 98.1% with the RSDs of below 7.0% and the limit of detection of 0.003 to 0.006 μg/g.2) 2,6-Dinitroaniline pesticide residues were not detectable in 10 leaf samples and 22 cigarette samples,which accounted for 20% and 44% of leaf samples and cigarette samples,respectively;the pesticide residues were more or less detectable in the other samples,however which were lower than the guidance residue levels recommended by CORESTA.3) The detection rates of flumetralin,pendimethalin,butralin,isopropalin,benfluralin and trifluralin were 45%,30%,8%,3%,1% and 1%,respectively.4) The pesticide residues were detected in 7 domestic cigarette samples and 21 imported cigarette samples,in which flumetralin and pendimethalin were the main residues in imported and domestic cigarette samples,respectively.5) All of six 2,6-dinitroaniline pesticide residues were detected in imported tobacco leaf samples,in which the detection rates of flumetralin,pendimethalin,butralin,isopropalin,benfluralin and trifluralin were 48%,32%,20%,8%,4% and 4%,respectively.6) Three of the 2,6-dinitroaniline pesticide residues were detected in 15 domestic leaf samples,which accounted for 60% of domestic leaf samples,the detection rates of flumetralin,pendimethalin and isopropalin were 40%,32%,and 4%,respectively.