Urchin-like Bi₂S₃ modified disposable SPCE for vanillin detection: Experimental and DFT insights into the oxidation...

Vanillin, a synthetic flavoring compound extensively used in the food and pharmaceutical industries, has drawn increasing attention due to potential health concerns associated with its artificial origin and high intake levels. In this work, we report the development of a highly sensitive and selective electrochemical sensor based on urchin-like Bi₂S₃-modified SPCE for detecting vanillin. A simple hydrothermal approach was utilized to synthesize Bi₂S₃, then systematically characterized using structural, spectroscopic, morphological, and electrochemical techniques to assess properties. The modified electrode was employed for vanillin quantification using differential pulse voltammetry, which offered a remarkable limit of detection of 7 nM with a broad linear detection range spanning from 1 nM to 99 μM. The proposed sensor reveals excellent practical applicability, as evidenced by high recovery rates (98-99%) in real food sample analysis. In addition to this, the computational investigation was utilized to understand the chemistry of vanillin oxidation during the electrochemical process.