Determination of sulphur- and chlorine-containing pesticides with an electrolytic conductivity detector

Abstract

The response of a number of sulphur-containing compounds, some of which also contained chlorine and nitrogen, were investigated using both the pyrolytic and oxidative modes of operation of the Coulson electrolytic conductivity detector. The effects of variation in furnace temperature and oxygen flow were studied. Half-scale responses for thirty-six sulphur compounds obtained in the pyrolytic mode at 850°, were in the 6–100 ng range which compared favourably with flame photometric detection in the sulphur mode. Also in the pyrolytic mode, a similar range of responses was obtained from a study of thirteen organochlorine insecticides. Responses were found to be linear in the range 2 to 1000 ng of sulphur with as low as 0.5 ng of sulphur and/or chloine being detected. In the pyrolytic mode nitrogen-containing compounds produced interference. The use of silver scrubbers for chloride removal in the oxidative mode although imparting selectivity also resulted in decreased sulphur response and lack of reproducibility.