Real-Time Process Control Sensor for Measuring Arsenic Concentration in Water

Arsenic contamination in drinking water is a severe health risk to populations throughout the world. In recognition of this risk, the U.S. Environmental Protection Agency recently lowered its water standard for arsenic from 50 ppb to 10 ppb. To comply with the new standard, there is an urgent need to develop new, simple, and effective treatment/monitoring systems that can be qualified to monitor and remove this toxic substance from water. Currently, accurate measurement of arsenic in drinking-water at levels impacting health currently requires laboratory analysis with sophisticated facilities, expensive techniques, and a trained staff not easily available or affordable in many parts of the world. The objective of this research is to develop and demonstrate an easy-to-use reliable, field deployable, and practical real-time sensor device for rapid on-site quantitative determination (at ppb levels) of dissolved arsenic metals in drinking water. The proposed monitor will employ fabricated thin-film boron-doped diamond microelectrodes arrays utilizing differential pulse anodic stripping voltammetry (DPASV) and select microarrays to detect both arsenate and arsenite in water. The combination of DPASV methods with microelectrode technology conveys a number of advantages for the rapid on-line measurement of arsenic in water without addition of supporting electrolyte while requiring little or no maintenance. Phase I will investigate the optimal design configuration, electrode material, and the operating conditions which will enhance sensitivity and enable reproducible detection or arsenic at low ppb levels with negligible interference. A compact packaged prototype instrument, including the sensor hardware and the corresponding electronic circuitry, will be developed in Phase II.