Towards safer foods: a high-performance quercetin-based potentiometric sensor for aluminum detection

Growing concerns about dietary aluminum exposure and associated health risks necessitate reliable detection methods. We developed an eco-friendly, screen-printed potentiometric sensor using quercetin as a natural ionophore for selective aluminum detection in foods and beverages. Among tested ionophores (quercetin, morin, calix[4]arene, and di-iodohydroxyquinoline), quercetin demonstrated superior Al³⁺ recognition. Incorporation of multi-walled carbon nanotubes (MWCNTs) enhanced sensor stability and performance. The optimized sensor exhibited a Nernstian response (21.9 ± 0.4 mV/decade) across 0.023-1070 μM with rapid 3-s response, maintaining stable performance within pH 3.0-5.0. Exceptional selectivity against interfering cations was achieved, with negligible interference effects. Practical validation using food samples and biological fluids confirmed real-world applicability. Density Functional Theory calculations substantiated the strong Al³⁺-quercetin binding affinity, providing molecular-level insight into the recognition mechanism. This sensor offers a sensitive, selective, and sustainable alternative to conventional aluminum detection methods, demonstrating significant potential for food safety monitoring and quality control applications.