Triarylmethane dyes on polymer film as optical sensors of atmospheric sulphur dioxide

A new method of atmospheric sulphur dioxide determination based on the reaction of sulphite ions with triarylmethane dye on polymer film has been developed. The addition of sulphite to aqueous solutions of triarylmethane dyes causes bleaching of the dye by formation of the sulphite complex. On the polymer film different aspects of the reaction such as the type of polymer, polymer film thickness, and atmospheric sulphur dioxide concentration have been studied. It was found that the process of diffusion has great influence on the reaction rate. That is why the most important thing for optimizing reaction conditions is choosing the polymer and plasticizer.