DETERMINATION OF HYPOCHLORITE IN WATERS BY STOPPED-FLOW CHEMI-LUMINESCENCE SPECTROMETRY

The reaction of hypochlorite with luminol was investigated by stopped-flow chemiluminescence spectrometry. The emission was observed by using a conventional fluorescence detector with its shutter off and set at 425 nm. Methods based on direct rate measurements on the formation and decay steps of the chemiluminescence process were used in addition to those involving conventional peak-height or peak-area measurements, which were evaluated comparatively. The methods yield linear responses over three orders of magnitudes with an RSD of about 1%. The proposed method, which is highly selective and rapid (80 samples h-1), was applied to the routine determination of hypochlorite in waters. The results were in good agreement with those obtained by the classical N,N-diethyl-p-phenylendiamine spectrophotometric method. © 1990.