Dummy molecularly imprinted magnetic nanoparticles for dispersive solid-phase extraction and determination of bisphenol A in water samples and orange juice

A novel dummy molecularly imprinted magnetic nanoparticle (MI-MNP) was prepared by a hybrid imprinting technique for dispersive solid-phase extraction (d-SPE) and determination of bisphenol A (BPA). 2,2'-Bis(4-hydroxyphenyl)-hexafluoropropane was used as the template molecule and Fe3O4 nanoparticle as the magnetic core. The MI-MNPs were characterized by FT-IR spectroscopy, thermo-gravimetric analysis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer. The adsorption tests showed that the MI-MNPs had a high binding ability for BPA and presented a fast binding kinetics. When used as a d-SPE sorbent, the MI-MNP showed high extraction efficiency, high enrichment factor and good reusability for BPA, and it can be easily recycled by a magnet. Furthermore, the dummy imprinting strategy can completely avoid the interference of the residual template in sorbent to determination of BPA. Using the MI-MNPs as sorbent, a d-SPE-HPLC-UV method was developed and successfully applied to the analysis of BPA spiked in water samples and orange juice and that in a certified sample with recoveries of 95.0-106.2% (RSD=2.5-4.5%), 93.3-100.0% (RSD=1.2-5.0%) and 100.3% (RSD=3.5%), respectively. The limit of detection (S/N=3) for all samples was 0.3 ng mL(-1). The new MI-MNPs can be utilized as a good d-SPE sorbent for BPA in environmental water samples and beverages.