Comparative study for separation of atmospheric humic-like substance (HULIS) by ENVI-18, HLB, XAD-8 and DEAE sorbents: elemental composition, FT-IR, 1H NMR and off-line thermochemolysis with tetramethylammonium hydroxide (TMAH).

摘要: Humic-like substances (HULIS) are significant constituents of aerosols, and the isolation characterization HULIS by solid-phase extraction methods dependent on sorbents used. In this study, we used following five methods: ENVI-18, HLB-M, HLB-N, XAD-8 DEAE, to isolate atmospheric at an urban site. Then conducted a comparative investigation chemical characteristics means elemental analysis, Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy off-line thermochemolysis with tetramethylammonium hydroxide. The results indicate that isolated using different show many similarities in composition structure. Some differences were however also observed between HULIS: HULISHLB-M contains relatively high content OCH group, compared HULISENVI-18 HULISXAD-8; HULISXAD-8 hydrophobic aromatic components, HULISHLB-M; HULISDEAE highest functional groups, as inferred NMR spectra, but great amount salts generally present thereby limited choices for characterizing materials (i.e., analysis TMAH thermochemolysis); HULISHLB-N has levels H N, N/C atomic ratio, includes N-containing which suggests it been altered 2% ammonia introduced eluents. summary, found preferable aerosols. These suggest caution is required when applying DEAE HLB-N isolating HULIS.