Chromium(III) ion-selective electrode based on 4-dimethylaminoazobenzene

A PVC-based membrane of 4-dimethylaminoazobenzene reveals a Nernstian potentiometric response (with slope of 19.5±0.6 mV/decade and a correlation coefficient of 0.999) for Cr(III) over a wide concentration range (1.66× 10−6–1.0×10−2 mol dm−3). The potential of this electrode is independent of pH in the range of 3.0–5.5. It has a fast response time of about 10 s and was used for a period of 3 months with good reproducibility. The detection limits of this membrane electrode was 8×10−7 M. the proposed electrode has been used as an indicator electrode in the potentiometric titration of Cr(III) with EDTA. This sensor exhibits a very good selectivities for Cr(III) over a wide variety of metal ions.