Highly selective sensor for trace asenite determination using anodic stripping voltammetry

An arsenite (As (III)) selective membrane of ionophore is deposited on a micro gold electrode surface to determine trace As (III) using anodic stripping voltammetry (ASV). Compared with a sensor without an ionophore membrane ("bare sensor"), the selective sensor's performance is greatly improved due to the membrane's superior As (III) permselectivity. The selective sensor's background current amplitude decreased from 1.375 μA to 0.320 μA, and its standard deviation decreased from 0.150 μA to 0.007 μA, leading to a higher signal-to-noise ratio (S/N). Meanwhile, the sensor's peak current standard deviation also dropped from 0.218 μA to 0.015 μA. Thus, low limit of detection (LOD) of 1.09 ppb is obtained for determining trace As (III). This simple, but highly sensitive selective sensor may lead to wide applications to on-line environmental monitoring.