Immunofluorescence Rapid Analysis of Bisphenol A in Water Based on Magnetic Particles and Quantum Dots

Bisphenol A (BPA) is widely used as a hardener in plastics production and its release and circulation in ecosystems lead to negatively impacts the human endocrine system. Therefore, there is a need for simple and efficient BPA monitoring tools. This paper presents a combination of two approaches for this purpose: the use of magnetic particles (MPs) as antibody carriers and immunochromatographic test strips based on quantum dots (QDs) for recording labeled immune complexes. Initially, free antigen binds to the MP-specific antibody conjugate, concentrating the sample to a final volume of 200 µL. A competitive interaction then occurs in the analytical zone of the test strip with immersion in a QDs solution. The visual detection limit of BPA was 2.7 μg/mL, the instrumental detection limit was 0.03 μg/mL, and the working range of quantification was 0.3-100 μg/mL (reproducibility was 7.7%, R² = 0.985). Concentration using MP reduces the detection limit by 100-fold (0.3 ng/mL). The developed test was used for qualitative control of the presence and quantitative determination of BPA content in samples of drinking and natural water (the detection rate is in the range of 94-110%).