Development of Nanosensors for Arsenic Detection in Drinking Water

Arsenic (III) poisoning is among the most significant public health concerns worldwide, and arsenic is among the WHO’s top ten most toxic chemicals. Millions of people in more than 50 countries are consuming arsenic polluted water. Long term exposure to arsenic-contaminated water or food may cause cancer (e.g., kidney and lungs) and skin diseases. The WHO and EPA recommended the maximum contaminant limit to 10 μg/L (10ppb) in drinking water. Traditionally, High-tech lab instruments such as ICP-MS, atomic fluorescence spectroscopy (AFS), and atomic absorption spectroscopy (AAS) are used. However, these instruments are highly expensive and cannot be used for on-site detection. Nanomaterials based sensors are cheaper, robust, portable, sensitive, and selective. Gold nanoparticles (AuNPs) based materials are the best candidates for developing sensors due to their optical properties and better conductivity. We report an efficient and user-friendly sensitive and selective AS (III) colorimetric sensor to screen contaminated water samples. AuNPs change the color from red to blue, and this shift is proportional to the amount of arsenic present in the water. The detection limit with the naked eye is 50 μg/L, whereas, with UV/Vis spectroscopy, it is 3 μg/L.