Laboratory Calibration of an Electronic Tongue for the Detection of Lead and Cadmium in Water

Heavy metals such as lead and cadmium in water present a major environmental and health risk. Conventional methods of heavy metal detection in water involve sampling and subsequent transport to a laboratory for testing. Standard spectroanalytical instruments are expensive, bulky and require trained personnel for operation and cannot be implemented for on-site sensing. There is also the risk of exposure of contaminated media to field workers and laboratory personal. This research describes a novel handheld electronic tongue for qualitative and quantitative analysis of lead and cadmium in water. The electronic tongue consisted of a miniature potentiostat, silver/silver chloride reference electrode, platinum counter electrode, and a glassy carbon working electrode. The potentiostat was programed to perform both square wave and differential pulse anodic stripping voltammetry. Laboratory calibration tests were conducted to identify and measure concentrations of lead and cadmium in samples of water. A pretreatment electrolyte solution was used to increase sensitivity. The resulting data was analyzed using regression tree analysis. The device and methodology developed in this research were capable of detecting lead and cadmium at low parts per billion limits.