Construction of a tri-channel sensing array based on multimetal-doped CDs nanozymes for fingerprint pattern recognition of food antioxidants.

Simultaneous and accurate detection of structurally similar food antioxidants remains challenging. Existing nanozyme arrays, which focus on external conditions rather than intrinsic catalytic properties, exhibit limited signal diversity and discriminative power. This study developed three CDs with tailored peroxidase-like activities via controlled metal doping. Under identical conditions, they displayed intrinsic kinetic differences, serving as a multi-channel fingerprint source. A three-channel colorimetric sensor array constructed from these CDs enabled simultaneous qualitative (0.5-50 μM) and quantitative detection of 6 representative antioxidants covering diverse structural classes as model analytes. Response patterns were resolved using principal component and hierarchical cluster analyses. Integrated into a smartphone-assisted portable platform, the method demonstrated high accuracy, robustness, and anti-interference capability in juice and tea analysis. This work establishes a new design paradigm for high-performance sensor arrays based on programmable intrinsic fingerprints and provides a reliable tool for portable multiplexed antioxidant analysis in complex systems.