Sensitive electrochemical determination of hydrogen peroxide in milk and water utilizing AgNPs@Sn MOF nanozyme

The detection of H₂O₂ by a non-enzymatic electrochemical sensor is demonstrated using the deposition of silver nanoparticles on a tin metal-organic framework (AgNPs@Sn MOF). Coupling Sn MOF with the AgNPs significantly amplifies the electro-analytical performance due to the higher porosity, synergistic effect, and enhanced active surface area for the analyte interaction, entailing the faster interfacial transfer of electrons. The synthesized material was explored using different characterization techniques, revealing the surface morphology, crystalline size and nature, and availability of different functional groups. Additionally, AgNPs@Sn MOF nanozyme effectively oxidizes 3,3',5,5'-tetramethylbenzidine (TMB) to oxidized-TMB(oxTMB) and o-phenylenediamine (OPD) to oxidized-OPD(oxOPD) product along with the generation of •OH radicals posing an excellent peroxidase-like activity in an acidic medium. Under the optimized experimental conditions, the colorimetric detection and the electrochemical sensing of H₂O₂ are facilitated with the LOD of 70 nM in the linear range 0.1-50 µM and 37 nM in the linear range of 0.1-30 µM, respectively. Notably, the practical utility of the sensor was demonstrated by sensing H₂O₂ in a real sample, achieving a recovery range of 97-106% and 96-106% for milk and water, respectively.