Determination of humic acid in natural waters by flow injection analysis with chemiluminescence detection

A fast and sensitive direct chemiluminescence flow injection procedure for determination of humic acid in natural waters was developed. N-bromosuccinimide (NBS) after on-line hydrolysis was used as a reagent evolving chemiluminescence by the oxidation of humic acid. Use of glycine as a sensitizer enhances the signal magnitude about 100 times. The detection limit is 0.012mgl-1 and 180 samples per hour can be determined. Almost all substances occurring in typical fresh water at normal level do not disturb the determination. Only phenols with one hydroxyl group are serious interferents, which were removed by evaporation.