Abstract
Methods for the identification and determination of dichloroacetic acid (DCA), trichloroacetic acid (TCA) and chloral hydrate (CH) in water have been studied. DCA, TCA, and CH in a tap water were preconcentrated by the use of XAD-column adsorption and diethyl ether elution technic followed by the methyl ester derivatization. The solution obtained was analyzed for DCA, TCA, and CH by GC/MS in negative ion detection mode. Results indicated clearly the presence of above compounds in the tap water. The mass fragmentograms obtained were similar to those obtained in analysis of the chlorinated aqueous solution of humic acid.
For the routine method of determining DCA, TCA, and CH in tap water, an electron capture gas chromatography preceded by the solvent extraction technic was developed and applied to the analysis of selected tap water samples. Results showed that minimum determination limits (unit μg·1-1) were 1.0, 0.5, and 0.2 for DCA, TCA, and CH respectively with 50ml sample taken, and that the totals of DCA, TCA, and CH concentrations in tap waters were found to be comparable to that of trihalomethanes except the cases of tap waters which were subjected to the activated carbon adsorption process.
