Determination of Cr(VI) in Water with Amperometric Detection at Conductive Polymer Electrodes

摘要

Electrochemical sensors can provide sensitive detection for monitoring of contaminant leakage from storage areas, plume movement in ground and surface water, and residual contamination following cleanup using inexpensive, portable equipment. While hexavalent chromium, Cr(VI), exhibits slow electron transfer kinetics at most electrodes, it is catalytically reduced by the reduced form of polyaniline (PANI). In the present device, the reduction of PANI oxidized by Cr(VI) provides an analytical signal proportional to Cr(VI) concentration in aqueous samples, allowing amperometric detection of Cr(VI) with ppb detection limits. Arrays of PANI-coated microelectrodes exploiting this electrocatalytic scheme provide significant improvements in S/N and limit of detection over larger electrodes. Calibration curves, limits of detection, S/N ratios, and effects of interferences on the sensor response in a flow injection analysis configuration are presented.