Paper-based manganese and β-cyclodextrin sensors for colorimetric sulfur dioxide detection.

Reported herein is a novel detection method for sulfur dioxide in aqueous solutions, in which the presence of sulfur dioxide leads to color changes of filter paper modified with both β-cyclodextrin and manganese. This detection method is rapid (less than 5 min required for complete color change), sensitive (limits of detection as low as 33 ppm), broadly applicable (tolerant of a range of pH values), and practical (color changes can be observed via naked eye detection and quantified via straightforward color analysis). Extensive optimization of each component provides insight into the unique stabilizing effect of cyclodextrin in preventing the filter paper from permanganate-induced degradation, and mechanistic analysis points to an oxidation-reduction reaction as responsible for the observed color changes. Overall, these results lay the groundwork for the development of practical sulfur dioxide sensors for use in the food and beverage industry, and provide precedent for the use of cyclodextrin as a stabilizing force in paper-based chemical sensors.