Preparation of Molecularly Imprinted Magnetic Stir Bar for Bisphenol A and Its Analysis on Trace Bisphenol A in Actual Water Samples

Abstract

In this paper, a new method for the preparation of a molecularly imprinted polymer (MIPs)-coated magnetic stir bar for bisphenol A (BPA) is proposed. The MIPs were prepared using BPA as the template molecule, and the sol-gel technique was employed to coat the MIPs onto the surface of a glass tube, which contained an internal magnetic core. The morphology and structure of the MIPs and the coating on the glass stir bar were analyzed using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Parameters affecting the extraction efficiency, such as extraction time, stirring speed, desorption solvent, and desorption time, were optimized. To evaluate the selective adsorption performance of the BPA-MIPs coating, molecularly imprinted stir bar sorptive extraction (MIPs-SBSE) was used in combination with high-performance liquid chromatography (HPLC) for the detection of BPA in deionized water, tap water, bottled water, and reservoir water. The results showed that under the optimized conditions, the MIPs coating exhibited better adsorption capacity and selectivity for BPA compared to the non-imprinted coating. The BPA-MIPs-SBSE could be reused for at least five cycles without a significant decrease in its selective adsorption ability. The recoveries of BPA in the four actual water samples ranged from 70.53% to 93.10%, with relative standard deviations of 4.49% to 8.69%. The practical application demonstrated that this method is simple, convenient, selective, and sensitive, making it suitable for the analysis and detection of trace amounts of BPA in complex samples.