A Long-Term Stable Sensor Based on Fe@PCN-224 for Rapid and Quantitative Detection of H(2)O(2) in Fishery Products

Hydrogen peroxide (H(2)O(2)) has been reported to be used for the illegal treatment of fishery products in order to obtain “fake” freshness. Residues of H(2)O(2) in food may be of toxicology concern. In this study, a nonenzymatic sensor was developed based on Fe@PCN-224 metal–organic frameworks wrapped by Nafion to detect H(2)O(2) concentration. The hybrid structure of Fe@PCN-224 was fabricated by incorporated free Fe(III) ions into the center of PCN-224, which was ultra-stable due to the strong interactions between Zr(6) and the carboxyl group. Scanning electron spectroscopy images exhibited that Nafion sheets crossed together on the surface of Fe@PCN-224 nanoparticles to form a hierarchical and coherent structure for efficient electron transfer. Electrochemical investigations showed that the Fe@PCN-224/Nafion/GCE possessed good linearity from 2 to 13,000 μM (including four orders of magnitude), low detection limits (0.7 μM), high stability in continuous monitoring (current remained nearly stable over 2300 s) and in long-term measurement (current decreased 3.4% for 30 days). The prepared nanohybrid modified electrode was effectively applied to H(2)O(2) detection in three different fishery products. The results were comparable to those measured using photometrical methods. The developed electrochemical method has a great potential in detecting the illegal management of fishery products with H(2)O(2).