Song X.C., Wu J.Y., Pang J.L., Wu Y.F. and Huang X.J.. 2021. Journal of Hazardous Materials, 411:125141
In this study, a novel sorbent based on task specific monolith doped with Fe3O4 was in situ fabricated in capillary and acted as the extraction medium of magnetic field-reinforced in-tube solid phase microextraction (MFR/IT-SPME) to trap and preconcentrate mercury species which were coordinated with dithizone to form chelates. Various characterization technologies evidenced that the obtained monolithic adsorbent presented porous and super paramagnetic properties, and possessed abundant functional groups. Results evidenced that the implementation of magnetic field during extraction stages enhanced the extraction efficiency of studied Hg chelates from 48.5% to 75.3% to 69.9-94.4%. Under the optimized extraction parameters, the introduced MFR/IT-SPME was online coupled to HPLC/DAD to quantify mercury species at ultra-trace levels in various water samples. Limits of detection varied from 0.0067 μg/L to 0.016 μg/L, and the RSDs for precision were below 7.5%. Additionally, related extraction mechanism was deduced and revealed multiple forces co-contributed to the enrichment. The reliability and accuracy of suggested online approach for speciation analysis of mercury was well proved by confirmatory experiments.
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| Figure 1. HPLC chromatograms of studied mercury species before treatment (a), after treatment with IT-SPME (b) and treatment with MFR/IT-SPME (c). Conditions: magnetic field intensities in adsorption and desorption steps were 20 Gs and 30 Gs, respectively; volume and flow rate of sample were 3.0 mL and 0.10 mL/min, separately; volume and flow rate of sample were 0.08 mL and 0.04 mL/min, separately; sample pH was controlled at 4.0; the spiked concentrations for MeHg+, EtHg+, PhHg+ and iHg2+ were all 20.0 µg/L. |
