N-doped biomass-derived carbon dots nanozymes with photo-enhanced activity for dual-mode detection of tert-butylhydroquinone in food.

Synthesis of highly active carbon dots nanozymes remains challenging. Using fresh garlic and ethylenediamine as precursors, nitrogen-doped carbon dots nanozymes (N-CDs) were fabricated in this study. The N-CDs exhibited light-responsive oxidase-like activity and blue fluorescence. For comparison, the carbon dots (CDs) without ethylenediamine doping demonstrated remarkable catalytic activity. Following doping with ethylenediamine, the maximum reaction rate and specific activity of N-CDs were approximately 1.4 times and 2 times those of CDs, respectively, indicating that nitrogen doping significantly enhanced the catalytic activity. Based on the catalytic performance and fluorescence properties of N-CDs, a dual-mode sensor was constructed for the detection of tert-butylhydroquinone (TBHQ), achieving detection limits of 0.19 μM and 0.05 μM for the colorimetric and fluorescence methods, respectively. Portable on-site detection of TBHQ in real samples was realized by integrating the sensing platform with a smartphone, providing a new strategy for the preparation of high-performance nanozymes.