II. Mitt.: Verhalten in Tomatenpflanzen

The metabolism of dimethoate and its N-butyl homologues in tomato plants has been studied by use of ³²P and ³⁵S labelled initial products. The preparation of thiol-³⁵S-labelled dimethoate is described. Formation and break down of dimethoxon and N-tert.-butyl-dimethoxon have been measured by radio-thin layer chromatography. The calculated biological half times have been compared with those in aqueous buffer solutions; remarkable differences between dimethoate and dimethoxon derivatives have been observed. The extension of the N-alkyl chain causes a more rapid biological breakdown. The technique described is also useful for the comparison of other organophosphorus compounds (OPC).