Uniformly distributed Cu2O/Cu nanoparticles supported on graphite phase carbon: An enhanced peroxidase mimic for total antioxidant capacity assay

The measurement of total antioxidant capacity (TAC) is vital for evaluating the nutrient content of foods and beverages. The development of novel mimetic enzyme materials with high catalytic activity has led to the creation of highly sensitive methods for TAC assessment. In this study, we introduce a simple and efficient approach for preparing uniformly distributed Cu 2 O/Cu nanoparticles supported on graphite-phase carbon (g-C@Cu 2 O/Cu NPs). These g-C@Cu 2 O/Cu NPs demonstrate excellent peroxidase-like (POD-like) enzymatic activity and exhibit a strong binding affinity for TMB, with a K m value of 0.24 mM. A colorimetric analytical platform for TAC assessment was developed, utilizing g-C@Cu 2 O/Cu NPs, TMB, and H 2 O 2 as the chromogenic system. The method achieved a limit of detection for ascorbic acid as low as 0.15 μM, with a linear range from 0.5 to 100 μM. Furthermore, this method was successfully applied to evaluate TAC in real samples, highlighting its significant potential for food nutritional analysis.