Chlorine sensing by optical techniques

Techniques of diffuse reflectance and fluorescence spectroscopy have been utilized for the development of new quantitative methods for the analysis of chlorine. The reflectance method involves the use of a dry reagent chemistry, prepared by immobilizing (sigma) -tolidine on a nylon 66 membrane, which is interrogated by means of optical fibers. Chlorine concentrations in the range 0-5 ppm can be measured with a limit of detection of 0.043 ppm. The fluorescence technique is demonstrated by the measurement of quenching of 9-vinylanthracene by chlorine. Efficient quenching of fluorescence of this dye is observed with a Stern-Volmer constant of 8667 M-7. The findings demonstrate the possibility of developing an analytical method for the determination of chlorine based on fluorescence quenching and optical fibers.