CLEANUP AND CONFIRMATION PROCEDURES FOR GAS-CHROMATOGRAPHIC DETERMINATION OF PESTICIDE-RESIDUES IN CONTAMINATED WATERS .1.

The effects of sulphuric acid, potassium hydroxide and chromic acid on eleven organochlorine and ten organophosphorus pesticides were invest igated. The treatments destroy some pesticides totally or partially, l eave others unaltered and have a clean-up effect. These reactions can be used to confirm the presence of an identified pesticide. The clean- up extracts in the environmental samples facilitate the identification of the organochlorine and organophosphorus pesticides and their quant itative analysis. The results obtained for contaminated surface waters show the usefulness of these methods for multi-residue capillary gas chromatography without the need for other additional separative chroma tographic steps to avoid interferences or the use of a highly sensitiv e mass spectrometer for confirmation.