Extraction of lead in human blood serum using functionalized metal-organic framework-coated glass magnet as adsorbent through stir bar sorptiven extraction

Abstract

In this work, a glass magnet coated with a thiol-functionalized metal-organic framework was used as an adsorbent to efficiently extract lead ions in the presence of other ions in real samples. One of the most studied face-centred cubic metal-organic frameworks (MOFs) with side pockets and nanoscale channels for film growth is HKUST-1. However, the growth of a thiol-functionalized metal-organic framework (HKUST-1-SH) on a glass magnetic surface as a coating for sorptive stir bar extraction (SBSE) is challenging. HKUST-1 was grown on a glass magnet by liquid phase epitaxy at room temperature. Moreover, a thiol-functionalized metal-organic framework coated on a glass magnet (HKUST-1-SH@Glass Magnet) was successfully synthesized using a simple post-synthesis strategy. The formation of HKUST-1 and HKUST-1-SH on the glass magnetic surface was confirmed and determined by scanning electron microscope images (SEM), energy dispersive X-ray spectrometer (EDS), ATR-IR spectra, and XRD patterns. Some parameters affecting the extraction efficiency, such as pH, extraction time, stirring speed, desorption time, sample volume and elution volume, were studied to improve the sensitivity of the method used. A linear dynamic range of 0.04–30 µg L−1 and a detection limit of 0.005 µg L−1 were obtained under optimal conditions with satisfactory precision and a relative standard deviation of 2.5 % (n = 10, CPb2+ = 15 μg L−1). The extraction efficiency for the determination of lead ions in blood serum samples varied in the range of 95.6 %to 106.2 %.