Zeolitic imidazolate framework-based magnetic stir bar for micro-solid phase extraction of persistent organic...

In this study, a micro-solid phase extraction method based on a ZIF-based magnetic stir bar was developed for the detection of six persistent organic pollutants in water. This method involved the fabrication of magnetic particles by loading ZIF materials with Fe₃O₄, which were then combined with self-assembled stir bar technology and a magnetic stirring apparatus to achieve semi-automated extraction, thereby establishing an semi-automated Fe₃O₄@ZIF stir bar micro-solid phase extraction method. Through optimization experiments on parameters such as the type and amount of Fe₃O₄@ZIF, extraction time, elution solvent, pH, and salt content, the optimal extraction conditions were determined as follows: 0.2 g of Fe₃O₄@ZIF-8, an elution solvent consisting of ethyl acetate and n-hexane (2:1), pH = 10, and 5% NaCl. Under these conditions, the recovery rates of the six persistent organic pollutants ranged from 54.0% to 89.5%, with detection limits between 0.19 μg/L and 0.57 μg/L, and relative standard deviations (RSD) of 6.2% to 9.1%. This method, leveraging stir bar technology and magnetic particles for semi-automated extraction and separation, was time-saving, energy-efficient, and environmentally friendly. The prepared ZIF-based magnetic stir bar was portable, making it highly suitable for on-site sampling and extraction, thereby offering strong practical applicability.