Nanostructured Ni-Zeolite Y and Carbon Nanohorns Electrode for Sensitive Electrochemical Determination of B-Group Vitamins.

This work presents the fabrication and analytical application of nanostructured Ni-zeolite (NiZY) and carbon nanohorns (CNHs) modified glassy carbon electrode (NiZY/CNHs-GCE) in the differential pulse voltammetric (DPV) determination of vitamin B2 (VB2) molecules. The synergistic combination of NiZY and CNHs significantly enhances the electrochemical performance of the sensor, as confirmed by structural, textural, morphological, and electrochemical studies. The redox behavior of VB2 on NiZY/CNHs-GCE was found to be adsorption-controlled, involving a two-electron, two-proton reversible reduction process. Under optimized conditions, the DPV response of NiZY/CNHs-GCEs in McIlvaine buffer solution (pH 3.4) exhibited a linearity in the VB2 concentration range of 0.01 to 0.20 mg L-1 (r = 0.9993) with a detection limit of 3.2 µg L-1 (8.6 × 10-9 mol L-1). Furthermore, well-resolved reduction peaks of vitamins B2 and B9 (VB9) enabled their simultaneous and selective detection, with linear ranges of 0.01 to 0.20 mg L-1 for VB2 and 0.01 to 0.16 mg L-1 for VB9. The proposed analytical method, characterized by high selectivity and robustness, was successfully applied in the determination of both vitamins in commercially available dietary supplements, achieving relative errors within -6.2% to 2.7%.