Fabrication of polypyrrole-coated magnetic particles for quinone extraction from fine atmospheric particulate matter

Abstract

In this paper, a magnetic solid phase extraction method was developed for the analysis of five quinones (oxygenated polycyclic aromatic hydrocarbons) in fine atmospheric particulate matter (diameters within eight ranges and all below 10 μm). The extraction adsorbent, polypyrrole-coated Fe₃O₄ (Fe₃O₄@PPy) nanoparticles, was synthesized by an ultrasonic-microwave cooperative method. The synthesis time was dramatically shortened to 4 h compared to conventional heating for 20 h. The Fe₃O₄@PPy nanoparticles demonstrated porous morphologies and exhibited magnetic properties (M_s = 51.0 emu g⁻¹). The target quinones could be captured directly by Fe₃O₄@PPy due to the formation of the π–π complex and hydrophobic interactions between PPy and quinones and separated by using a magnetic field with only 0.5 mL desorption solvent. The total preparation time was within 20 min. Then an analytical method for the determination of quinones by Fe₃O₄@PPy extraction coupled with gas chromatography mass spectrometry (GC/MS) was developed. The LODs, based on a signal-to-noise ratio (S/N) of 3, were in the interval of 0.01–0.20 ng m⁻³. Method recoveries for spiked real samples ranged from 71.5 to 93.2%, and intra-day and inter-day precisions were in the ranges of 5.8–9.2% and 6.8–12.1%, respectively. The developed method combined magnetic extraction and GC/MS for the determination of five quinones in fine particulate matter, and showed significant improvements considering the sample preparation time and solvent consumption.