Voltammetric sensor based on tin dioxide nanoparticles for the determination of taxifolin

A voltammetric sensor based on a glassy carbon electrode (GCE) modified with tin dioxide nanoparticles dispersed in N-hexadecylpyridinium bromide (NPs SnO2) was developed for the determination of taxifolin. Modification of the electrode surface provides an increase in the reversibility of the electrode reaction, as well as a significant increase in the redox currents compared to GCE (2.3 and 3.3 times for the anodic and cathodic peaks, respectively). The morphology of the electrode surface according to scanning electron microscopy data is represented by uniformly distributed on the electrode surface SnO2 NPs of spherical shape with a diameter of 20-40 nm, which leads to a 3.9-fold increase in the effective area of the electrode and a 143-fold increase in the heterogeneous electron transfer rate constant. The electrooxidation of taxifolin was found to proceed with the participation of protons. Mixed control with diffusion and adsorption contributions was confirmed for the electrode reaction. In differential pulse mode against Britton-Robinson buffer with pH 6.0, the range of determined taxifolin contents is 0.075-25 μM with a detection limit of 70.7 nM. The obtained characteristics are comparable to other electrochemical approaches, but the proposed approach is simpler and more rapid, and does not require complex modification of the electrode. The developed sensor was successfully applied in the analysis of dihydroquercetin (taxifolin) based bioadditives. The results obtained were compared with the data of coulometric titration by electrogenerated bromine.