A novel field deployable filter paper based amperometric gas sensor for the measurement of arsenic in water

• A novel electrochemical AsH3(g) sensor and system were developed.
• A field portable potentiostat was developed to measure arsenic in drinking water.
• The sensor is easy to fabricate using carbon fiber and silver foil.

The presence of toxic levels of inorganic arsenic in drinking water is a worldwide problem. Measurement of millions of samples in the field for arsenic is an analytical challenge and the first step to solve the problem. Here, we developed a novel electrochemical arsine sensor and system based on the cell: C(s)/I3−I2, AsH3(g/aq)//I3−, I2 AgI(s)/Ag(s), where I3−/I2 mediated AsH3(g/l) oxidation which occurred on the C(s) electrode. The sensor system requires 50 μL of 10 mM iodine solution and a small piece of filter paper placed inside a novel electrochemical cell. The cell exhibited highly efficient arsine mass transport with a limit of detection of 15 μg/L As(III) in water. A mathematical model of mass transfer of AsH3(g/aq) and following electrochemical reaction was developed and applied to explain the experimental data. Groundwater samples containing arsenic were measured to prove its utility in a field deployable instrument.