Dual-mode strategy for the determination of vanillin in milk-based products based on molecular-imprinted nanozymes

The inclusion of artificial food additives such as vanillin in infant formula should be strictly monitored to mitigate potential negative impacts on the dietary habits and health of infants. This raises a necessity of an accurate inspection and prompt feedback of vanillin in infant foods. In this study, colorimetric and fluorescent dual-mode assays based on CuNS/Fe₃O₄@MIPs were established to detect vanillin selectively and sensitively. Quantification of vanillin could be achieved with linear detection ranges of 1-100 μM and 1-150 μM for the colorimetric and fluorescent assays respectively. The corresponding detection limits were 0.11 and 0.10 μM respectively. The CuNS/Fe₃O₄@MIPs-based dual-mode assays exhibited good selectivity and stability for vanillin detection in infant formula and milk-based foods. Hence, this method can serve as a reliable tool for the cost-saving, effective and quantitative determination of vanillin in infant foods, with the potential to replace conventional instrumental analysis.