Determination of chlorine by fluorescence quenching

Chlorine is used extensively in the chemical industry and for disinfection of drinking water. Many methods have been reported for the determination of chlorine species. Fluorescence quenching to determine chlorine is a promising method because of its high sensitivity and selectivity. This study focuses on development of a sulfonamide-based collection system for low levels of chlorine in air. Quantitation of chlorine is based on the quenching of the fluorescence signal observed when chlorine reacts with the fluorescent sulfonamide compound. Both a direct fluorimetric and a fluorescence-HPLC method have been established. Linear relationships are found between the fluorescence intensity or HPLC peak area and the amount of chlorine. Detection limits are in the ppb range or better. These methods have been applied to water samples. Experiments have also shown that sulfonamide-treated dihydroxypropylated silica can effectively collect gas-phase chlorine