A portable, disposable, and low-cost optode for sulphide and thiol detection

In this study, a portable, disposable, and low-cost ionophore-based optical sensor is presented for the monitoring of sulphides and thiols. This sensor was obtained by fixing a classical dye, 5,5 '-dithiobis(2-nitrobenzoic acid) (Ellman's reagent, ELL), on an unusual solid support. Indeed, we decided to anchor the dye on the commercial paper sheet known as the "Colour Catcher (R)" (herein, named under the acronym CC), commonly used in the washing machine to prevent colour run problems. The device obtained can be regarded as an optical sensor since the indicator dye fixed on the solid material changes its spectral properties (colour and hence the UV-vis spectrum) upon contact with the analyte. The relationship between the analyte content and changes in the UV-vis spectrum of the sensor has been provided using partial least squares regression (PLS).