Magnetic molecularly imprinted polymers for selective extraction and determination of naphthols

The authors describe a magnetic molecular imprinted polymer (MMIP) for the extraction and detection of naphthols synthesized by surface imprinting technology using 1-naphthol as the template. The MMIPs were characterized by FT-IR spectroscopy, X-ray diffraction, thermogravimetric analysis and vibrating sample magnetometry. They are shown to be viable magnetic adsorbents for various naphthols. The effects of sample volume, pH value, ionic strength, adsorption time, and desorption solvent, volume and time were optimized. Following elution with methanol, the naphthols were quantified by HPLC. Under optimal experimental conditions, the MSPE-HPLC method exhibits a linear range from 0.02–25 mg·kg −1 for naphthols. The limits of detection (LODs) are 6 μg·kg −1 for both naphthols. The method was applied to the determination of 1-naphthol and 2-naphthol in hair coloring products. Recoveries are in the range of 88.8–101.6% with relative standard deviations of less than 9.3%. Graphical abstract Schematic of the preparation of magnetic molecularly imprinted polymers (MMIPs) using 1-naphthol as the template.