Posted by Accurate on-site analysis of food quality is of great significance for ensuring public health. Among them, ascorbic acid (AA) is an essential micronutrient widely used as an additive in juices and drugs to improve food quality and human health. In this work, we developed food-grade Fe-β-Cyclodextrin(Fe-β-CD) nanozymes based on inexpensive and readily available β-cyclodextrin and iron ions for the detection of AA. Fe-β-CD confirmed excellent peroxidase-like activity and oxidized colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to oxide TMB. AA could inhibit the oxidation reaction and cause blue to fade. Based on the above principles, Fe-β-CD nanozymes exhibited a low detection limit (3.4 μM) for detecting AA, with a wide linear range (10–300 μM). This method had been successfully used for the detection of AA in fruits and vitamin C tablets, and the results were consistent with the specified values. More importantly, an integrated smartphone-assisted Fe-β-CD@test strip colorimetric application platform constructed by one-pot method, the test strip also had better stability, and could be combined with smartphones to achieve convenient AA detection without using any instruments, which showed enormous potential for rapid and low-cost colorimetric detection of AA.
Jun Li, Jie Zhang, Xianling Yang, Ao Kong, Nan Wang, Jie Tang, Xiaoqi Yu (2025) One-pot synthesis smartphone-assisted test strip based on food-grade Fe-β-Cyclodextrin nanozymes for rapid colorimetric analysis of ascorbic acid in foods and supplements. Food Chemistry 466, 142158.
https://doi.org/10.1016/j.foodchem.2024.142158
Caption of featured image: (A) Schematic diagram of smartphone-assisted detection of AA by Fe-β-CD@test strip; (B) Plots of RGB values and different concentrations of AA (10–300 μM). Inset is the corresponding photographs; and (C) The detection AA values tested by colorimetric and smartphone-assisted methods, compared the label values.