Voltammetric determination of iron(III) using sputtered platinum thin film

A sputtered platinum thin film was fabricated by using photolithography, sputtering, and a lift-off method. The sputtered Pt grains were uniformly dispersed in the film as observed from FE-SEM images to form a compact film with fairly homogeneous size. Square wave voltammetry was used to directly detect Fe(III) with this electrode, typically at a working potential of 0.63 V (vs. Ag/AgCl). The method had a 90 ppb detection limit and worked in the 0.3-5 ppm concentration range. This value meets the requirements set by the World Health Organization. In addition, the stability and reproducibility of the electrode were superior (with RSDs of 3.363% for 5 repetitive measurements). For real tap and well water samples, the electrode gave the well-defined peak for Fe(III) without showing any enrichment in Fe(III). The results from real water analyses were in agreement with those obtained by the UV-Vis method. (C) 2019 Elsevier Ltd. All rights reserved.