GQDs@ZIF-8-based "turn off" molecularly imprinted fluorescence sensor for the detection of histamine in aquatic products.

Strict monitoring of histamine (His) is essential for evaluating aquatic product spoilage and ensuring food safety. Therefore, developing on-site detection techniques featuring rapid response, cost-effectiveness and high accuracy has grown increasingly imperative. In this work, a "turn-off" molecularly imprinted fluorescence sensor (GQDs@ZIF-8@MIPs) for detecting His was designed, integrating luminescent metal-organic frameworks (GQDs@ZIF-8) with molecularly imprinted polymers (MIPs). Briefly, MIPs acted as the specific recognition element to achieve selective binding of His, while GQDs@ZIF-8 served as both the carrier matrix and signal output element. When His was specifically adsorbed by MIPs, the fluorescence of GQDs@ZIF-8 was quenched by His via the photoinduced electron transfer (PET) mechanism. Herein, quantification of His could be realized by establishing the relationship between the target concentration and the degree of fluorescence quenching. The experimental results revealed that this sensor had excellent performance, with its linear range covering 0.5-40 μM and an ultralow limit of detection of 0.016 μM. The successful construction of this sensor provides an innovative technical path and theoretical support for the detection of His in aquatic products.