The effect of continued use on the condition and sensitivity of screen-printed electrodes in the detection of total As under acidic conditions.

Increasing surface roughness of the working electrode due to the deposition of nanoparticles (a) before and (b) after continued use under acidic conditions, whereupon the charge of the reduction peak increased from 3.49 μC to 23.9 μC. (c) The increase in the intensity of the reduction peak with repeat CV measurements (including deposition at -2 V). (d) The relationship between the intensity of the reduction peak and the sensitivity of the electrode towards the detection of total As. The CV scans in clean 0.5 M H₂SO₄ and total As detection (167 μg L^-1 As(V), 0.1 M HCl, 60 s deposition) were performed consecutively, repeatedly alternating between the two measurements.