Hydrogel-confined fluorescent copper nanoparticles for intelligent, anti-interference mercury ion detection with smartphone-assisted analysis.

The detection of mercury ions (Hg2+) in food is important because Hg2+ is a highly toxic heavy metal ion that can cause severe health risks even at trace levels. The majority of detection techniques, however, are limited in their suitability for on-site testing due to their high equipment and personnel requirements. Here, we introduce a CuNPs@hydrogel bioreactor that is easy to operate and made for precise on-site Hg2+ screening in challenging conditions. The detection kit's high accuracy, stability, and portability, as shown by experimental results, allow for intelligent detection of Hg2+ with a detection limit as low as 0.13 μM and a detection range of 0.01-200 μM. Moreover, when the kit was applied to real samples such as milk and tea, it achieved favorable recovery rates. Notably, by enabling smartphone-based visual detection of Hg2+ without costly instrumentation, this portable detection kit shows potential for on-site environmental and food-safety monitoring.