FeCuCe trimetallic nanoalloys exhibiting superior peroxidase activity for colorimetric detection of total antioxidant capacity

Total antioxidant capacity (TAC) serves as a valuable parameter for evaluating the quality of natural foods and plants. We report the synthesis of FeCuCe nanoalloys with a high density of uniformly distributed catalytic sites that function as efficient peroxidase-like nanozymes for sensitive colorimetric TAC detection. Kinetic analysis demonstrated strong FeCuCe nanoalloy affinities for both 3,3,5,5-tetramethylbenzidine (TMB) and H₂O₂ substrates, with <i>K</i> _m values of 3.29 ± 0.23 mmol/L and 0.17 ± 0.01 mmol/L, respectively. This enabled the development of a sensitive ascorbic acid (AsA) colorimetric detection platform with a detection limit of 0.69 μmol/L. FeCuCe nanoalloy efficacy for antioxidant assessment was further validated using cysteine (Cys) and glutathione (GSH). The assay successfully evaluated TAC in several fruits and fruit juice beverages, demonstrating potential for rapid, cost-effective on-site TAC screening.