Flow-injection analysis with chemiluminescent detection of sulphite using Na2CO3-NaHCO3-Cu2+ system

A simple flow-injection system with chemiluminescent detection for selective determination of sulphite is described. The light accompanying the reaction between sodium carbonate and copper(II) mixture solution with sulphite is detected. The concentration of sulphite is proportional to the chemiluminescence intensity in the range of 1.0 x 10(-6)-5 x 10(-4) mol l(-1). The limit of detection is 5 x 10(-7) mol l(-1) and the relative standard deviation is 4.6% for the 5 x 10(-6) mol l(-1) sulphite solution in nine repeated measurements. This method has been successfully applied to the determination of sulphite in wines. The possible reaction mechanism is also discussed.