Rapid determination of free active chlorine in water by diffuse reflectance spectroscopy after reaction with polyurethane foams Original Research Article

A simple and sensitive method for the determination of free active chlorine in waters has been proposed. It is based on the reaction of surface toluidine groups of polyurethane foams (PUF) with chlorine under acid conditions. A yellow-colored product of the reaction is determined immediately in the PUF using diffuse reflectance spectroscopy. The calibration curve is linear over 0.2–6 μg/ml or 5–150 μg in 25 ml of final aqueous solution. Interference from various foreign substances has been examined and the method has been successfully applied to the determination of free residual chlorine in water.