Portable detection platform integrated with smartphone-assisted ratiometric fluorescence sensor for visual on-site detection of lead(Ⅱ) in aquatic products

Lead ion (Pb 2+ ) pollution seriously threatens the quality of aquatic products. In this study, a ratiometric fluorescence sensor consisting of tangerine fluorescent Mn:ZnS QDs (T-QDs) and blue fluorescent Fe-MOF (B-MOF) was developed for selective recognition of Pb 2+ . Upon exposure to Pb 2+ , the fluorescence of T-QDs was quenched while the fluorescence of B-QDs was slightly changed, causing the changes of fluorescence colors from tangerine to blue with a detection limit (LOD) of 3.79 nmol/L. The sensor also had the strengths of low cost, easy to operate, excellent sensitivity and selectivity. Significantly, a portable detection platform integrated with the sensor was constructed to achieve on-site visual detection. As expected, the detection platform was successfully applied for testing Pb 2+ with the LOD of 7.78 nmol/L. The strategy may not only provide a great capacity for on-site monitoring of Pb 2+ in aquatic products but also expand application in environmental pollution detection.