Absorbance‐Based Spectroelectrochemical Sensor for [Re(dmpe)3]+ (dmpe=dimethylphosphinoethane)

Abstract

AbstractA spectroelectrochemical sensor was developed for [Re(dmpe)3]+ as a nonradioactive analog for [Tc(dmpe)3]+. The sensor consists of an optically transparent electrode (OTE) coated with a thin film of sulfonated polystyrene‐block‐poly(ethylene‐ran‐butylene)‐block‐polystyrene (SSEBS). Colorless [Re(dmpe)3]+ was reversibly oxidized to [Re(dmpe)3]2+ (λmax=530 nm). [Re(dmpe)3]+ preconcentrated by ion‐exchange into the SSEBS film, resulting in a 20‐fold increase in peak current compared to a bare OTE after 1 h of exposure to aqueous [Re(dmpe)3]+ solution. Detection of [Re(dmpe)3]+ at concentrations down to 2×10−6 M was accomplished by electrochemical modulation of the complex and monitoring absorbance by attenuated total reflectance (ATR).