Carboxymethyl hexanoyl chitosan drop-coated simple disposable paper electrochemical sensor for quality monitoring of vanillin

The food and pharmaceutical sectors frequently utilize vanillin (VAN), a food ingredient with a pleasing flavor and aroma. However, excessive consumption of VAN causes several health problems, including liver and kidney damage, headaches, skin conditions, nausea, and vomiting. To prevent health problems, it is crucial to identify and control the amount of VAN in food and drugs. Here, we have synthesized carboxymethyl hexanoyl chitosan (CHC), a water-soluble polymer, that has been extensively studied through surface morphological and optical characterizations. Furthermore, because of their affordability, ease of use, and simple manufacturing processes, disposable paper electrodes (PPE) offer several benefits in biosensors. Therefore, to detect VAN electrochemically, CHC has been drop-coated on a PPE. High catalytic activity for the electro-oxidation of VAN in phosphate buffer solution (PBS; pH 7.4) is demonstrated by the CHC-coated PPE. The electrochemical sensor demonstrated the limit of detection (LOD) of 29 nM (S/N = 3), and the peak current for VAN was found to be linear to the concentration ranges between 7.8 μM and 200 μM under ideal conditions. Additionally, in the presence of VAN at 200 μM, the in-house developed sensor demonstrated non-interference towards glucose, citric acid, ascorbic acid, sucrose, and Cu²⁺ at higher concentrations (400 μM). Nonetheless, real sample analysis of commercial VAN (with and without) ice-cream demonstrated the successful detection of the analyte, which further authenticates the potential of the sensor in real world applications. The current study provides a novel method for detecting industrially relevant analytes upon specific CHC based surface modifications of the sensor.