Abstract
Gas chromatographic methods using selective detectors have been applied successfully to the determination of haloforms, herbicides and chlorophosphate esters in water extracts. Electron capture detection has been used for the determination of the four haloforms, CHCl 3, CHCl 2Br, CHClBr 2 and CHBr 3 in pentane extracts. The very low detection limits render both the extracts and calibration solutions highly susceptible to contamination, and precautions necessary for their handling and storage are described. Mass spectrometric single ion monitoring of gas chromatographic effluents has been used for the determination of the herbicides MCPA, MCPB and Mecoprop in methylated ether extracts. Possible interference from other components of the water extracts is discussed, and it is concluded that more than one ion should be monitored for each herbicide to minimise the interference. A flame photometric method involving detection at 528 nm has been developed for the determination of chlorophosphate esters in dichloromethane extracts. The method is extremely specific for phosphorus compounds, but some interference from sulphur compounds may be observed. This can be minimised by the use of high efficiency capillary columns. Detection limits and linear response ranges for the methods are given, and detector selectivities are discussed. Typical chromatograms are shown, and representative results for raw and treated waters are also given.
Published Version
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