Rapid Determination Of Trace Bisphenol A Using A Fluorescent Molecularly Imprinted Polymer

Objective: Bisphenol A （BPA） is used as a primary raw material to make polycarbonateplastics and epoxy resins which are wildly used in a variety of products of daily life, suchas food storage containers and food packaging. BPA can leach from these products withester bonds subject to hydrolysis and non-polymerized monomer residues. And BPA maycontaminate the food stored in these products. Thus, BPA has been a potential threat tohuman health. As one of the most ubiquitous environmental estrogen, BPA can causeadverse health effects on human being by mimicking and interfering with hormonalactivities to affect growth, development, and reproduction. In order to protect human health,it is essential to monitor the concentration of BPA in food. Until now, the widely usedmethods for determination of BPA in food often require time-consuming samplepretreatment and expensive instrumentations, which are not suitable for rapid processing ofmultiple food samples. In this study, a fluorescent molecularly imprinted polymer（fluorescent MIP） which has specific recognition and binding sites for BPA was preparedby using a new fluorescent chemical dansyl methacrylate as the functional monomer. And anew method for determination of trace BPA was established based on the fluorescent MIP,with simple operation, time saving, high sensitivity and high-throughput.Methods: In this study, BPA was chosen as the template and dansyl methacrylate as thefunctional monomer to synthesize fluorescent MIP by precipitation polymerizationmethod. Morphology, selectivity, binding characteristics and fluorescent characteristics ofthe fluorescent MIP were evaluated. A new method for determination of trace BPA wasestablished based on the fluorescent MIP applied to microplate reader. Results: The main results are summarized as follows:1. The functional monomer was confirmed as dansyl methacrylate and its molecularformula was C18H22N2SO4.The prepared fluorescent MIP was polymeric microspheres witha mean diameter of208±33nm. The Bmax（the maximum number of binding sites） of theMIP and NIP were2.53×10^-6and1.99×10^-6mol/g, respectively. The fluorescent MIP hadmaximal excitation at348nm and maximal emission at515nm. The fluorescence offluorescent MIP was rapidly quenched upon BPA addition, with the degree of quenchingcorrelating with the concentration of BPA. In the presence of several analog compounds（BPC, BPZ and E2）, the fluorescent MIP can still bind BPA selectively and showdose-dependent fluorescence quenching in response to the added BPA.2. Under the optimum conditions, the calibration graph of established method was linearwith R²=0.9972in the ranges from0.1-1mg/L BPA standard solution. The intra-day and theinter-day RSD were both less than4.2%. The intra-day and the inter-day recoveries ofdifferent concentrations of BPA for the spiked samples （milk and fish） ranged from91.2%to110.1%with RSD less than13.2%.Conclusions: Trace BPA in complex food samples can be rapidly and accurately detectedby the established method based on the fluorescent MIP.