Bimetallic Fe/Ni metal organic framework-based hypoxanthine biosensor for early monitoring of freshness changes of aquatic products

The timely detection of freshness changes of aquatic products is crucial. In this study, we have developed a reliable, cost-effective, and user-friendly method for rapidly detecting hypoxanthine using a xanthine oxidase (XOD)/nanozyme enzymatic cascade system. The nanozyme, derived from the Fe 7 /Ni 3 metal–organic framework (Fe 7 Ni 3 MOF), exhibited good peroxidase-mimetic activity and stability. Our proposed XOD/Fe 7 Ni 3 MOF enzymatic cascade system demonstrated a linear response to hypoxanthine in the range of 3–70 μM, with a low detection limit of 1.39 μM. We also analyzed hypoxanthine in actual aquatic products, achieving spiked recoveries ranging from 90.04 % to 107.37 %. The correlation coefficient between our developed colorimetric method and the HPLC method was 0.98. Importantly, our proposed method holds several advantages over alternative techniques, particularly in terms of cost-effectiveness, precision, and speed. Consequently, this methodology shows great promise for the early detection of freshness changes in aquatic samples.