Aquasift: A low-cost, hand-held potentiostat for point-of-use electrochemical detection of contaminants in drinking water

The difficulty of detecting small quantities of contaminants in water supplies currently threatens the health of millions of people worldwide, as consumption of contaminated water has been associated with both cancerous and noncancerous health risks. Existing technologies make it possible to very accurately quantify contaminant levels in water; however the expense, extensive training, and off-site analysis required by these methods prevent wide scale use. Electrochemical detection offers many advantages, such as portability, minimal use of instrumentation, and ready integration with electronics. With a goal of water quality interventions, we have presented an affordable and point-of-use platform capable of detecting small amounts of arsenic in water samples. Our electrochemical system utilizes a three-electrode sensor integrated with a handheld, self-designed potentiostat called Aquasift. Aquasift's hardware is simplified as much as possible to maintain affordability and relies on firmware complexity to provide functionality comparable to more expensive bench top potentiostats. Several optional on-board digital filters are available for signal conditioning. The Aquasift can sample at a rate up to 1KSPS and the output data rate is adjustable from 1KSPS down to 1 sample per second. The board uses 12-bit data converters to provide a voltage resolution of 806 micro volts. The Aquasift is powered directly from the USB port and requires no additional power source. We compare the results obtained from the Aquasift of arsenic testing to those obtained from a commercially available bench top potentiostat. The results show Aquasift's comparable accuracy to the commercial analyzer, and demonstrate that our proposed system is a more affordable, portable alternative to laboratory testing.