Determination of traces of iron by thin-layer spectroelectrochemistry

Abstract

The complex of iron with Chrome Azurol S (CAS) was studied using a long path-length thin-layer spectroelectrochemical cell with dual working electrodes. A method for the determination of traces of iron proposed, based on the variation in the absorbance between the oxidized and reduced state of the complex (Δ A), Δ A was proportional to iron concentration over the range 0–3 μg ml −1. Compared with the conventional spectrophotometric determination of iron using CAS, the selectivity was improved because the analytical signal here depended on both the spectral and the electrochemical behaviour of the tested species. Iron was determined in water samples by this method. A concept characterizing the sensitivity of the spectroelectrochemical signals is also presented.