Stable iridium-modified boron-doped diamond electrode for the application in electrochemical detection of arsenic (III)

Preparation of stable iridium-modified boron-doped diamond electrodes through electrodeposition was studied. The electrode was prepared by wet chemical seeding and thermal annealing that performed before and after the electrodeposition process in order to get a homogeneous deposition. The modified electrode from each step was characterized using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Raman and X-Ray photoelectron spectroscopy (XPS) to understand the surface topography and its elemental composition. In addition, cyclic voltammetry for arsenic (III) was performed to examine the electrochemical behavior of the modified diamond. At an optimum condition in a phosphate buffer solution pH 3 and a scan rate of 50 mV/s, a linear calibration curve in the concentration range of 1–100 μM with a detection limit of 4.64 μM was achieved. Excellent stability and repeatability were also observed with relative standard deviations of 2.6% and <0.4%, respectively. Additionally, the electrode exhibited good linearity and sensitivity towards the measurement of arsenic (III) in both arsenic (III)-added tap water and lake water samples.