Magnetic dummy molecularly imprinted polymer nanoparticles as sorbent for dispersive solid-phase microextraction of phthalate monoesters in human urine samples

Abstract

In this work, a simple and efficient dispersive solid-phase microextraction (DSPME) method based on magnetic dummy molecularly imprinted polymer nanoparticles (MMIPs) was developed for the extraction of five phthalate monoesters (mPAEs) from human urine samples. The MMIPs synthesized by sol–gel reaction and surface imprinting were analyzed by transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometry, and thermogravimetric analysis. The obtained results demonstrate that the MMIPs prepared herein are characterized by high selectivity, good adsorption capacity (124.5 mg/g), excellent reusability (over five sorption–desorption cycles), and fast adsorption rates (about 30 min to equilibrium) with respect to five mPAEs. In addition, the MMIPs can be easily separated from the sample solutions due to their good magnetic susceptibility (34.0 emu/g). Using MMIPs as sorbent material in DSPME, five mPAEs in three human urine samples were extracted, and then analyzed by high-performance liquid chromatography (HPLC). Based on the obtained results, this method shows good linearity in the range of 1–100 mg/L for monomethyl phthalate, monoethyl phthalate, and monobutyl phthalate, in the range of 1–80 mg/L for monobenzyl phthalate, and in the range of 1–50 mg/L for monoethylhexyl phthalate. Moreover, good recovery (80.0%–101.0%) of all five mPAEs was observed at three spiked level with relative standard deviations of 0.6–6.6%. Overall, the results reported herein indicate that the prepared MMIPs can be used as sorbent material for the dispersive solid-phase microextraction of phthalate monoesters in human urine samples.