Tailoring nanostructured Zr-doped ZnO and β-cyclodextrin on a carbon sensor for ultra-sensitive electrochemical detection of vitamin B6-pyridoxine hydrochloride

Water-soluble vitamin B6 (VB6), also known as pyridoxine, is essential for various metabolic and physiological functions. In this work, a β-cyclodextrin-modified carbon paste electrode incorporating zirconium-doped zinc oxide nanoparticles (Zr–ZnO/β-CD@BCPE) was developed for the sensitive electrochemical detection of VB6. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Electrochemical investigations using cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) revealed excellent electrocatalytic activity toward VB6 oxidation, with optimal response at pH 4.2 within the potential range of 0.7–1.2 V. The SWV analysis exhibited a linear detection range of 0.6–10 µM, a limit of detection (LOD) of 1.16 nM, and a limit of quantification (LOQ) of 3.88 nM, demonstrating the high sensitivity of the proposed sensor. The Zr–ZnO/β-CD@BCPE also showed good reproducibility, stability, and selectivity, enabling reliable determination of VB6 in pharmaceutical and water samples.