A novel paper-based sensor for determination of halogens and halides by dynamic gas extraction.

A new chemosensor in the form of indicator paper, which is sensitive to chlorine and bromine concentrations, is proposed. A simple technique of sensor preparation in a laboratory without expensive reagents is described. The method provides uniform and reproducible distribution of the reagent. A possibility to use the sensor for chemical analysis when combining with dynamic gas extraction with the application of scanner technologies and color image processing is demonstrated. Sensitive and selective techniques of chlorine, bromine, chloride, and bromide determination have been developed. The limits of detection of bromine, chlorine, bromide, and chloride have been found to be 0.06, 0.28, 0.5 and 1.4 µmol L-1 respectively. A scheme of successive determination of these analytes in the same sample including selective halides oxidation is proposed. In the simple and available set-up used for dynamic gas extraction, sample decomposition, oxidation of halide-ions and extraction of the formed halogen take place simultaneously while the color reaction of halogen interaction with the sensor is conducted out of the analyzed solution with reagents. This approach provides high selectivity and good analytical characteristics of analysis of such complex samples as foods, pharmaceutical formulations, and different water objects. The method is easy-to-use, cost-effective, time-efficient and promising for determination of other volatile compounds.