Lead(II) ion detection in purified drinking water by nickel hexacyanoferrate-modified n-Si electrode in presence of dihydroxybenzene

To develop feasible probes for heavy metal ions has been considered as one of the most important research topics, due to the significance in monitoring and evaluating the toxicity of environmental water system, especially for the drinking water. This work provided a probe for Pb(II) ion detection in purified drinking water. Nickel hexacyanoferrate (NiHCF) films were prepared by vacuum evaporating nickel fine wire and transforming in a potassium ferricyanide solution on the front surface of platinum coated n-silicon. The transformed NiHCF film shows a reversible insertion electrochemistry and possesses electrocatalytic activity under illumination. The NiHCF-modified electrode was used as photoelectrode and dihydroxybenzene as photocurrent mediators to make up photoelectrochemical (PEC) sensor for Pb(II) ion detection in purified drinking water based on a two-electrode cell in absence of reference electrode and operated at zero working voltage. We have investigated the effects of Pb(II) ions on the photocurrent of hydroquinone or catechol in the purified water. The assay demonstrated good photocurrent responses by adding different concentrations of Pb(II) ion into purified drinking water with a linear range of 20–1560 nM and the limit of determination (based on S/N = 3) is 4.8 nM and 5.3 nM for the presence of hydroquinone and catechol, respectively.