Evaluation of silica nanoparticles coated by imprinted polymer for enzymatic determination of hypoxanthine using ferroin as freshness sensor in fish samples

In this study, the Hx (hypoxanthine) imprinted polymer was synthesized, and xanthine oxidase (XOD) oxidized the Hx on the surface of the imprinted polymer. Enzymatic production yielded uric acid (UA) and hydrogen peroxide (H₂O₂), which reacted with the ferroin reagent to form the red color in situ on the imprinted polymer. SEM and FTIR spectroscopy were used to characterize the synthesized polymer. Subsequently, the effects of different interference ions and parameters such as pH and time were optimized. The newly prepared adsorbent was found to be highly efficient and selective for extracting Hx based on the results. To investigate the applicability of the new method, fish samples were allowed to stand at room temperature for durations ranging from 0 to 24 h. During this time, Hx levels were measured at various intervals, and color differences were examined. Additionally, the approach was quantitatively optimized. Hx determination was verified using HPLC-DAD after the color was adsorbed with ethylene glycol following elution.