Photoelectrochemical amperometric sensing of cyanide using a glassy carbon electrode modified with graphene oxide and titanium dioxide nanoparticles

The authors describe a modified glassy carbon electrode (GCE) for the amperometric determination of cyanide ions. First, the surface of TiO₂ nanoparticles was modified with aminopropyltriethoxysilane (AS). These were then deposited, along with graphene oxide (GO) nanosheets, on the surface of the GCE. The modification steps were followed by reductive deposition of reduced 4-nitrophenol (rNPh). The GO/TiO2-AS-rNPh electrode was used to design a photoelectrochemical amperometric cyanide assay which works in pH 7 solution, best at 0.35 V (vs. Ag/AgCl). Characteristics of merit include a 0.1 μM detection limit, a 165.5 nA·nM⁻¹·cm⁻² sensitivity, and a dynamic linear range extending from 0.1 μM to 60 μM. The selectivity of the assay was tested by recording the response of the modified GCE to potentially interfering anions and was found to be very good. The inherent photocatalytic activity, good stability, wide linear analytical range, short response time, low detection limit and good selectivity make this assay highly advantageous .