Gas Chromatographic Determination of Insecticide Residues in Dried and Fermented Tobacco Samples of Field Trials and Vegetation Studies/Gaschromatographische Bestimmung von Insektizid-Rückständen an getrockneten und fermentierten Tabakproben aus Feld- und Vegetationsversuchen

From the chlorinated hydrocarbons aldrin and heptachlor, applied to the soil for the control of insects, no aldrin or heptachlor could be found in the tobacco leaves. Small quantities of dieldrin (0.01-0.09 ppm) and heptachlor epoxide (0.28-3.5 ppm) were, however, detected. The roots contained remarkable quantities of aldrin and dieldrin, heptachlor I + II + III, and heptachlor epoxide. Other metabolites were not found in tobacco. If lindane was applied to the soil only traces of this insecticide (0.01.-0.16 ppm) were taken up by the tobacco plants and could be identified in the lower and upper leaves. On application after transplanting, aldrin (0.3-3.6 ppm) and heptachlor I + II and heptachlor epoxide (0.1-28 ppm) were found in the middle and top leaves. From the insecticides of organic phosphorous compounds (parathion, metasystox, malathion and bromophos) usually no residues could be found in air-cured tobacco when they were applied 2 weeks before harvesting. On tobacco with high content of resins (dry climate) we found small quantities of organic phosphorous compounds (0.3-5 ppm) if these were applied as dust