Spectrophotometric determination of arsenic via arsine generation and in-situ colour bleaching of methylene blue (MB) in micellar medium

A new spectrophotometric method has been developed to determine arsenic in parts-per-million (ppm) level. It is based on the colour bleaching of methylene blue (MB) in anionic micellar medium. Arsine gas was formed by borohydride reduction of arsenite/arsenate. Arsine generation and colour bleaching (quantification of arsenic) could be done in one-pot. The presence of silver or gold nanoparticles makes the determination faster. Different calibration graphs at the three different ranges of arsenic concentration such as 0–8.63, 0–1.11 and 0–0.11 ppm were constructed and limit of detection (LODs) were found to be 1.3, 0.53 and 0.03 ppm, respectively. The method is simple, rapid, reproducible (relative standard deviations lies within ±5%) and eco-friendly. It is free from phosphate and silicate interferences and applicable for real sample analysis.