Advancements in Portable Voltammetry: A Promising Approach for Iron Speciation Analysis

Iron, a crucial element in our environment, plays a vital role in numerous natural processes. Understanding the presence and concentration of iron in the environment is very important as it impacts various aspects of our planet&rsquo:s health. The on-site detection and speciation of iron are significant for several reasons. In this context, the present work aims to evaluate the applicability of voltammetry for the on-site determination of iron and its possible speciation using a portable voltammetric analyzer. Voltammetry offers the advantage of convenience and cost-effectiveness. For iron (III) determination, the modification of a glassy carbon electrode (GCE) with an antimony-bismuth film (SbBiFE) using the acetate buffer (pH = 4) as a supporting electrolyte was used. The technique adopted was Square Wave Adsoptive Cathodic Stripping Voltammetry (SW-AdCSV), and we used 1-(2-piridylazo)-2-naphthol (PAN) as the iron (III) ligand. Linearity, repeatability, detection limit, and accuracy were determined using synthetic solutions: then, a Standard Reference Material (SRM) of 1643f Trace Elements in Water (iron content: 93.44 &plusmn: 0.78 &micro:g L&minus:1) was used for validation measurements in the real matrix. the accuracy of this technique was found to be excellent since we obtained a recovery of 103.16%. The procedure was finally applied to real samples (tap, lake, and seawater), and the results obtained were compared via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). The amount of iron found was 207.8 &plusmn: 6.6 &micro:g L&minus:1 for tap water using voltammetry and 200.9 &plusmn: 1.5 &micro:g L&minus:1 with ICP-OES. For lake water, 171.7 &plusmn: 3.8 &micro:g L&minus:1, 169.8 &plusmn: 4.1 &micro:g L&minus:1, and 187.5 &plusmn: 5.7 &micro:g L&minus:1 were found using voltammetry in the lab both on-site and using ICP-OES, respectively. The results obtained demonstrate the excellent applicability of the proposed on-site voltammetric procedure for the determination of iron and its speciation in water.