Thin-film polymeric sensors for detection and quantification of multivalent metal ions

Chemical sensors that reversibly respond to multivalent metal ions are described. These sensors consist of a thin polymeric sensing element that changes size upon reversibly binding analyte ions, particularly heavy-metal ions. The polymeric sensing elements have been bonded to thin metal-foil strain gauges to form sensors. In laboratory evaluations these sensors exhibit high sensitivity to Ba(II), Cd(II), Pb(II), Cr(III), and Cr(VI). Sensor response time is fast, ranging from several seconds to a few minutes. The selectivity and repsonse characteristics of these sensors depend on the composition of the polymeric sensing element. This paper describes the sensitivity and selectivity demonstrated by sensors containing three chemically different polymeric sensing elements. Potential applications of these sensors include in situ real-time monitoring of the heavy-metal content of ground and surface water, municipal water supplies, and household tap water.