Preparation of a functionalized magnetic metal–organic framework sorbent for the extraction of lead prior to electrothermal atomic absorption spectrometer analysis

Abstract

Dithizone functionalized magnetic metal–organic frameworks (Fe₃O₄/Cu₃(BTC)₂–H₂Dz) were successfully synthesized for the determination of trace levels of lead based on magnetic solid-phase extraction. The properties of the hybrid nanoparticles were characterized in detail by Fourier transform infrared spectroscopy, X-ray diffraction spectrometry, vibrating sample magnetometry, and scanning electron microscopy. The sorbents were conveniently separated from the complicated matrix easily with an external magnetic field. The metals were quantitatively desorbed and quantified by electrothermal atomic absorption spectrometry. The factors affecting the extraction process such as pH, sorbent amount, sample volume, eluent concentration and volume, and interfering ions were investigated and optimized. The adsorption capacity of Fe₃O₄/Cu₃(BTC)₂–H₂Dz was found to be 1.67 mg g⁻¹ for lead. The method had a linear calibration plot over the range of 0.01 to 5.0 μg L⁻¹ with a relative standard deviation of 3.2% at 0.5 μg L⁻¹ (n = 10). The detection limit was as low as 0.0046 μg L⁻¹. The results indicated that the proposed method based on Fe₃O₄/Cu₃(BTC)₂–H₂Dz was a novel, rapidly analysed, highly selective, and reliable assay for lead detection.