| Popis: |
A rapid and sensitive thin-layer chromatographic method has been developed for organo thiophosphate residue analysis. Compounds are resolved and identified on plates of aluminum oxide G with methylcyclohexane as mobile solvent and either 15 or 20% N,N-dimethylformamide as immobile solvent. A highly specific and sensitive chromogenic reagent (tetrabromophenolphthalein ethyl ester, AgN03, and citric acid) reacts with sulfur-containing phosphate esters which are detected at 0.05 μg, or less, for 11 of the 14 compounds examined. As little as 0.05 ppm of Diazinon, Trithion, Systox (thiono), malathion, and parathion were identified in the presence of kale, lettuce, and strawberry extracts. The method is approximately 20 times more sensitive than comparable paper chromatographic techniques. |
