The attempt to replace long-lasting chlorinated hydrocarbon insecticides with less-persistent chemicals has led. to increased use of phosphorus containing and carbamate pesticides. Although numerous analytical procedures are available for determining residues of a particular organochlorine and organophosphate pesticide on food products, there are only a few methods for tobacco. There is a great need for a rapid, accurate, and sensitive procedure capable of determining any of a large number of such pesticide residues. The Mills-Onley-Gaither (1) screening procedure for organochlorine pesticide residues has previously been adapted as a screening procedure for organothiophosphate pesticide residues in fruit and vegetables (2-5). Methods for carbamates are published (6, 7, 8, 9), two of them for tobacco. This paper describes the preliminary de.velopment of a general method for the organochlorine pesticides, water-insoluble and water-soluble organophosphorus pesticides, and metabolites derived from the latter.
A screening method has been developed for the qualitative and quantitative determination of vanillin, ethylvanillin, coumarin and dihydrocoumarin. The compounds are qualitatively determined by thin-layer chromatography after extraction of tobacco and purification of the extract. The quantitative determination is made by gas chromatography: Coumarin and dihydrocoumarin are determined directly and vanillin and ethylvanillin after silylation in the form of trimethylsilyl derivatives. Detection limit: thin-layer chromatography = 1 µg, gas chromatography = 0.02 µg. The coefficient of variation of the results obtained amounts to 2.4 % for vanillin and to 6.7 % for coumarin
Bestimmung von Carbaryl-Riickstanden (1.-Naphthyl-N-methylcarbamat) und Unden-Riickstanden (2-lsopropoxy-phenyl-N-methylcarbamat) wurden zwei Analysenmethoden fiir Carbaryl (1., 2) zur Bestimmung von Carbamat-Riickstanden auf Tabak kombiniert und modifiziert. Das vorliegende Verfahren gestattet die qualitative und quantitative Bestimmung von Carbaryl und Unden in griinem, getrocknetem und fermentiertem Tabak.
The screening procedure for the determination of pesticide residues in tobacco (organochlorine, organophosphorus and carbamate insecticides) published in 1970 has been improved by introduction of the dry-column chromatography as cleanup procedure. A new procedure has been developed for the detection of carbaryl and propoxur by gas chromatography. The extraction and cleanup method developed can be used to determine 11 organochlorine, 11 organophosphorus and 3 carbamate insecticides. The procedure can be applied to determine further insecticides and, in addition, fungicides, herbicides and metabolites. The recoveries of added pesticides at 0.5 ppm level are between 75 and 102 %. The coefficient of variation detected with parathion is 4.4 %
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