A shikimic acid derived carbon dots (SACNDs-FITC) for multi-modal detection and removal of Hg²⁺: Probe design, sensing performance, and applications in food analysis

The first shikimic acid derived fluorescent carbon dots (SACNDs-FITC) for multi-modal detection and simultaneous removal of Hg²⁺ is revealed. The fluorescence of SACNDs-FITC centered at 520 nm can be selectively quenched by Hg²⁺, while the emission centered at 420 nm remains constant which can be used for self-calibration. Naked-eye distinguishable color change from yellow to colourless under daylight and from green to blue under UV light could be observed for SACNDs-FITC in the real-time detection of Hg²⁺. Novel approaches that combine smartphone automated color hue (RGB and HSV) readout for intelligent Hg²⁺ analysis was developed. Moreover, SACNDs-FITC could work as an effective absorbent for Hg²⁺ with an adsorption capacity of 19.24 mg/g. Mechanism studies revealed the success of the post-modification strategy and the crucial role of -NCSN- groups in detecting and adsorbing Hg²⁺. Most importantly, multi-modal analysis of Hg²⁺ in celery cabbage and apples was performed using this analytical platform.