Magnetic Solid-Phase Extraction of Lead (II) from Water, Tea, and Linden Leaf Samples Using a Zirconium-Based Metal Organic Framework (Zr-MOF@Fe3O4) Prior to Determination by Flame Atomic Absorption Spectrometry

Magnetic metal organic framework (Zr-MOF@Fe₃O₄) was synthesized and applied as a solid-phase extractor to the separation and/or preconcentration of Pb(II) from water, tea, and linden samples prior to its determination by flame atomic absorption spectrometry. Zr-MOF@Fe₃O₄ were characterized by X-ray diffraction, scanning electron microscope with energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, and BET methods. The effect of eluent, pH, stirring time, amount of adsorbent, and interfering ions was investigated. Adsorption capacity of Zr-MOF@Fe₃O₄ and mean recovery of Pb(II) were found as 312.5 mg g⁻¹ and 96 ± 3%, respectively. Detection limit (LOD), quantification limit (LOQ), and linear working range were found as 3.9 µg L⁻¹, 13 µg L⁻¹, and 13–5000 µg L⁻¹, respectively. Precision and accuracy of the method were checked by analyzing standard reference materials and spiked water samples. Both percent relative error and RSD% were less than 4% in the analysis of standard reference materials.