Design of photoelectrochemical sensor based on mixed metal oxide modified TiO2-NTs for determination of galantamine in real sample

Photoelectrochemical (PEC) sensors are a kind of electrochemical methods which includes a light source and a suitable photoactive modified electrode. The light source excites a photoactive modified electrode to generate a photocurrent signal. Various active species, such as organic small molecules, metal complexes graphene nanocomposites and semiconducting nanoparticles have been investigated for PEC study [1]. Among them, nanoscale TiO2 has been widely considered one of the most promising photocatalytic materials due to its low cost, nontoxic, photostable properties and strong photooxidation ability [2]. Ti-nanotubes (NTs) were grown on titanium foils by electrochemical anodization in water-ethylene glycol solution containing ammonium fluoride. The anodization was conducted in the constant 25 V for 2 h. Then the as-prepared Ti-NTs electrode was calcinated at 450 ○C for 150 min [3]. Cobalt-copper alloy was electrodeposited on the TiO2 NTs using electrochemical coating method for 30 s under an applied potential of –1.0 V [4]. The photoelectrocatalytic oxidation behaviour of galantamine (Gal) was studied in the present work using the Co3O4-CuO modified TiO2-NTs electrode. The results showed remarkable enhanced UV light photoelectrochemical response of the Co3O4-CuO modified TiO2-NTs in comparison with TiO2-NTs and Co3O4/TiO2-NTs. The photocurrent of Gal oxidation (under the UV irradiation) was assessed using the hydrodynamic photoamperometric method in buffer solution. The optimum conditions for Gal determination were studied and citrate buffer solution (pH=4.2) and E=2.0 V (vs. Ag/AgCl reference electrode) were selected as an optimum supporting electrolyte and applied bias potential. It was found that the photocurrent of Gal was linearly dependent on the concentration of Gal in the range of 10 nM to 10 µM, and the detection limit of Gal determination was found to be 7.60 nM.