Correlation and digital signal processing techniques for the reduction of detection limits of bromate and bromide in model water samples by ion chromatography with direct ultraviolet detection

Bromate is a well known by-product produced by the ozonation (disinfection) of drinking water, of which the concentration is considered to be regulated to a low mu g/l level, Successful ion chromatographic methods of determination involve the implementation of concentration columns. As an alternative to concentration, it is demonstrated that the low mu g/l level can easily be attained using a simple and foolproof experimental arrangement of direct pseudo random injections of large quantities of the sample and ultraviolet (UV) detection at 204 nm with subsequent decorrelation of the detector signal. The approach, known as correlation chromatography, makes high demands to the reproducibility and other properties of the injection system. Although correlation chromatography is less sensible to spikes and baseline drift compared with normal chromatography, optimum results will be achieved by applying digital detector processing prior to decorrelation, combined with a proper modification of the eluent. This is demonstrated here. (C) 1997 Elsevier Science B.V.