A novel electrochemical sensor based on a P2W15V3@CNTs composite for the sensitive determination of baicalin

Abstract

Developing a rapid and accurate method for determining baicalin (Bn) content is of great significance for the quality control, pharmacological research, and clinical application of Scutellaria baicalensis. Herein, we fabricated a novel electrochemical sensor based on a composite material of a V-substituted Dawson-type polyoxometalate (POM, P₂W₁₅V₃) and carbon nanotubes (CNTs) for the sensitive detection of Bn. The P₂W₁₅V₃@CNTs composite was successfully prepared and characterized by transmission electron microscopy (TEM), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical techniques. Benefiting from the synergistic effect between P₂W₁₅V₃ and CNTs, the P₂W₁₅V₃@CNTs/GCE exhibited excellent analytical performance for Bn detection. Within the concentration range of 2.6–8.2 µM, the proposed electrode achieved a sensitivity of 2.843 µA µM⁻¹ and a detection limit of 26.4 nM (S/N = 3), coupled with favorable selectivity, reproducibility and stability. Moreover, we employed the P₂W₁₅V₃@CNTs-based sensor to detect Bn content in Scutellaria baicalensis samples, and the recoveries ranged from 101.2% to 106.3%, revealing its suitability for practical applications. This study presented a novel strategy for constructing a POM-based electrochemical sensing platform to monitor Bn.