Smart fluorometric sensing of metal contaminants in canned foods: a carbon dot-based dual-response system for quantifying aluminum and cobalt ions

초록

The leaching of aluminum and cobalt ions into canned foods, such as aluminum from canned tomato sauce and cobalt from canned tuna, raises concerns about potential health risks, making their accurate detection essential for food safety. In this study, we developed a novel ratiometric fluorometric sensor based on dual-emission carbon dots capable of selectively detecting aluminum (Al3+) and cobalt (Co2+) ions after a single excitation. The sensor exhibits distinct fluorescence responses: cobalt ions enhance the emission at 403 nm due to interactions with nitrogen and sulfur groups on the carbon dot surface, while Al3+ enhance the emission at 532 nm through binding with oxygen-rich groups such as carboxyl and hydroxyl. This differential response stems from the varying affinities of these metal ions for different functional groups, as confirmed through mechanistic studies and comprehensive characterization of the carbon dots, including TEM, UV-Vis, FTIR, and fluorescence lifetime analyses. The method demonstrates excellent sensitivity, with limits of detection (LOD) of 0.012 mu M for Co2+ and 0.06 mu M for Al3+. The sensor's performance was validated with real food samples, successfully determining Al3+ in canned tomato sauce and Co2+ in canned tuna. The method exhibited high selectivity with minimal interference, achieving recovery rates of 97.50-100.67% for Al3+ and 97.01-98.02% for Co2+. These findings underscore the robustness and practical applicability of the proposed sensor as a reliable tool for monitoring Al3+ and Co2+ in canned foods, ensuring food safety and compliance with regulatory standards.

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