Flow-injection chemiluminescence sensor for the determination of free chlorine in tap water

A novel chemiluminescence(CL) sensor combined with flow-injection analysis has been developed for deternlining free chlorine in tap water. The analytical reagent luminol was immobilized on an anion exchange resin column. While a volumn of sodium hydroxide passed through the column. luminol was eluted from the resin in alkaline aqueous solution and then mixed with a sample stream to react and produce CL. The CL emission intensity was correlated with the standard ClO- concentration in the range 1x10(-8) to 4x10(-5) g ml(-1). and the detection limit was 8x10(-9) g ml(-1) ClO-. Interfering metal ions present in water were effectively separated by a pre-column cation exchanger. A complete analysis, including sampling and washing, could be performed in 1 min with a relative standard deviation of less than 5%. The sensor was stable for over 200 times and has been applied successfully to the determination of ClO- in tap water.