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.