Smartphone-assisted mobile fluorescence sensor for self-calibrated detection of anthrax biomarker, Cu2+, and cysteine in food analysis

Dipicolinic acid (DPA), as a biomarker for Bacillus anthracis , is highly toxic at trace levels. Rapid and on-site quantitative detection of DPA is essential for maintaining food safety and public health. This work develops a dual-channel self-calibrated fluorescence sensor constructed by the YVO 4 :Eu and Tb- β -diketone complex for rapid visual detection of DPA. This sensor exhibits high selectivity , fast response time, excellent detection sensitivity, and the detection limit is as low as 4.5 nM in the linear range of 0–16 μM. A smartphone APP and portable ultraviolet lamp can assemble a mobile fluorescence sensor for on-site analysis. Interestingly, adding Cu 2+ ions can quench the fluorescence intensity of Tb 3+ . In contrast, the addition of cysteine can restore the fluorescence, allowing the accurate detection of Cu 2+ ions and cysteine in environmental water and food samples. This work provides a portable sensor that facilitates real-time analysis of multiple targets in food and the environment.