Dual-mode fluorometric and colorimetric sensor based on prunella vulgaris derived carbon dots for Co2+ detection in real water and food

Heavy metals exert adverse impacts on human health, ecosystems, and the environment. Accumulated Co 2+ poses severe threats to human health, consequently, the development of portable and reliable Co 2+ detection methods has become an urgent demand in the fields of environmental monitoring and food safety. Here, Chinese herbal medicine (CHM)-inspired carbon dots (P-CDs) were fabricated using prunella vulgaris as a carbon source and o -phenylenediamine (OPD) as a nitrogen source. The yellow emissive P-CDs enabled dual-mode (colorimetric and fluorometric) detection of Co 2+ , with a limit of detection (LOD) of 1.94 μM and 0.57 μM, respectively. The portable smartphone-based RGB mode strategy was also developed and achieved on-site effective detection with visible and intelligent treatment. The recoveries ranged from 90.3%–105.7% and were attained from the practical test in real water and food samples, demonstrating excellent sensing reliability and environmental tolerance. This study advanced the promising systematic development of functional CHM-derived CDs, and provided an innovative dual-modal strategy for the portable detection of heavy metals. This strategy offers a novel perspective for Co 2+ detection in real environmental and food samples; it is of great significance for investigating CHM-derived carbon active sites from unique insights.