A ratiometric fluorescence sensor based on CuZn quantum dots and FeMn quantum dots embedded imprinted polymer for ultrasensitive detection of bisphenol A with a smartphone analyzer

The hazards of bisphenol A (BPA) represent a significant public health concern, and developing accurate methods for its detection in water is of great importance for both human health and environmental protection. To address this, we have developed a dual-quantum dots fluorescent (FL) probe for highly efficient BPA recognition. This probe is fabricated by embedding iron‑manganese quantum dots (Fe Mn QDs) and copper‑zinc quantum dots (Cu Zn QDs) into a molecularly imprinted polymer matrix using a one-pot synthesis method. The constructed Fe Mn QDs/Cu-Zn QDs@MIPs sensor integrates dual FL emissions at 575 nm (Fe Mn QDs) and 525 nm (Cu Zn QDs) for specific recognition of BPA. Upon interaction with BPA, the sensor exhibits enhanced yellow fluorescence from Fe Mn QDs while the blue-green fluorescence of Cu Zn QDs is quenched. The fluorescence intensity ratio (F575 nm/F525 nm) demonstrates a single-exponential function relationship with BPA concentration. The employment of a dual-signal transduction mechanism enables the sensor to exhibit exceptional selectivity and ultrahigh sensitivity, with a wide linear detection range of 2.283–228.3 μg/L and a low detection limit (LOD) of 1.142 μg/L. To demonstrate its practical applicability, the sensor was employed for the quantitative detection of BPA in commercially bottled water, achieving satisfactory recoveries ranging from 96.0% to 104.4%. This work presents a practical and innovative approach for developing a ratiometric sensing system with dual fluorescence signals integrated with a smartphone-based visual detection platform for monitoring trace-level BPA.