Nanoporous films of different metal oxides were coated onto a titanium support (sputter coated with platinum or non-sputtered) and submitted to electrochemical impedance spectroscopy (EIS) testing. The arsenic (V) concentration (in an aqueous solution) was varied during the EIS testing to determine how each composite (metal oxide coating + support) would electrochemically respond to arsenic in solution and whether it would be a suitable material for an arsenic (V) sensor electrode. It was found that increasing the amount of metal oxide deposited (film thickness) did not always equate to greater sensitivity for arsenic detection and the support used (sputtered with platinum vs. non-sputtered) also influenced the sensing ability of the composite electrodes. Moreover, factors such as poor repeatability of the fabrication process (acidic SiO2 sol) and instability of the EIS curves at constant arsenic concentrations occurred with select metal oxide coatings (Fe2O3, TiO2 and Al2O3) and would be detrimental to the performance of the sensor. Of the coatings tested, the titanium support sputtered with platinum and coated with ZrO2 showed the most promise as an arsenic (V) sensor because of the separation and stability of its EIS curves with different arsenic concentrations and the high frequencies for which this occurred. (C) 2018 The Electrochemical Society.