Iron Determination in Deep Groundwater Wells by Anodic Stripping Voltammetry at an Iodine-Coated Platinum Electrode

Abstract

The presented work was pivoted on iron (II) determination in deep groundwater wells samples by using anodic stripping technique at an iodine-coated platinum electrode. The developed method was based on a preconcentration step for five min., followed by the potential scanning of an iodine-coated platinum electrode between the limit of hydrogen evolution (-0.25 V) and the beginning of iodine desorption from the electrode surface (+0.85 V). The anodic peak of the deposited iron to iron (II) oxidation was clearly centered at ca. 0.74 V. The anodic peak current showed an excellent linear response (R 2 = 0.996), within an iron (II) concentration range from 1 to 100 ppm. The obtained limit of detection (LOD) was 0.26 ppm and the limit of quantification (LOQ) was 0.85 ppm. Within the iodine-coated platinum electrode potential window the possible interferences by several ions were evaluated. The developed method was examined by iron (II) concentration determination in deep groundwater wells. The statistical comparisons between the two methods showed the absence of any significant difference between the obtained Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) values and our voltammetric method results, at P = 0.05. iron (II) determination; deep groundwater; stripping voltammetry and iodine-coated platinum electrode.