Micelle bound redox dye marker for nanogram level arsenic detection promoted by nanoparticles

The reduction of an SDS micelle bound dye (λmax at 660 nm), methylene blue (MB), by arsine gives a quantitative measure of arsenic concentration in the sub parts per million levels for a test sample. Arsine (AsH3) is generated in situ by NaBH4 from arsenic containing samples while present along with the other reagents. The extent of the micelle bound dye reduction was facilitated in the presence of Ag or Au nanoparticles. The micelle, in turn, helps to increase the collision probability between the dye and arsine and nanoparticles help the electron relay from AsH3 to the micelle bound dye. This physical effect has been depicted as a micelle catalyzed reaction. The calibration graph is valid for a wide range of concentrations. The linear dynamic range (LDR) is 0–0.11 ppm with the limit of detection (LOD) being 0.03 ppm. This method offers a simple, reproducible and cost effective technique for quantification of arsenic, free from phosphate and silicate interferences and applicable to real sample analysis.