MOE Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
Chemosphere. 2009 Nov;77(10):1419-26. doi: 10.1016/j.chemosphere.2009.09.002. Epub 2009 Sep 25.
Fulvic acids from the soil of Peking University (PF) and a Nordic river (NF) were separated into well defined sub-fractions using sequential elution techniques based on eluent polarity. The chemical properties of the fractions including: PF1 and NF1 (eluted by 0.01 M HCl), PF2 and NF2 (eluted by 0.01 M HCl+20% methanol), PF3 and NF3 (eluted by 0.01 M HCl+40% methanol), and PF4 and NF4 (eluted by 100% methanol), were characterized using UV-Visible spectroscopy, elemental analysis and (13)C NMR. The results showed that the UV absorptions of the elution peaks at 280 nm (A280) increased from PF2 to PF4 and NF2 to NF4. No elution peaks were observed for PF1 and NF1. The carbon contents increased from 43.34% to 51.90% and 43.06% to 53.26% while the oxygen contents decreased from 46.39% to 36.76% and 49.76% to 40.03% for PF1-PF4 and NF1-NF4, respectively. As a polarity indicator, the (O+N)/C ratio for PF1-PF4 and NF1-NF4 decreased from 0.88 to 0.62 and 0.89 to 0.58, respectively. The aromatic carbon content increased from PF1 to PF4 and NF1 to NF4, suggesting an increase of the hydrophobicity of these fractions. The polarity was positively related to the ratio of UV absorption at 250 nm and 365 nm (E2/E3), and negatively related to the aromaticity. A high positive relationship between the aromaticity and E2/E3 of fulvic acid fractions was also obtained. The use of an eluent with a decreasing polarity allowed to providing simpler fractions of soil and aquatic fulvic acids.
富里酸从北京大学（PF）和北欧河流（NF）的土壤中分离出明确的亚组分，使用基于洗脱剂极性的顺序洗脱技术。各组分的化学性质，包括：PF1 和 NF1（用 0.01 M HCl 洗脱）、PF2 和 NF2（用 0.01 M HCl+20%甲醇洗脱）、PF3 和 NF3（用 0.01 M HCl+40%甲醇洗脱）、PF4 和 NF4（用 100%甲醇洗脱），用紫外可见光谱、元素分析和（13）C NMR 进行了表征。结果表明，280nm 洗脱峰的紫外吸收（A280）从 PF2 到 PF4 和 NF2 到 NF4 增加。PF1 和 NF1 没有洗脱峰。碳含量从 43.34%增加到 51.90%和 43.06%增加到 53.26%，而氧含量从 46.39%减少到 36.76%和 49.76%减少到 40.03%，PF1-PF4 和 NF1-NF4 分别。作为极性指标，PF1-PF4 和 NF1-NF4 的（O+N）/C 比从 0.88 减少到 0.62 和 0.89 减少到 0.58。芳香碳含量从 PF1 到 PF4 和 NF1 到 NF4 增加，表明这些组分的疏水性增加。极性与 250nm 和 365nm 处的紫外吸收（E2/E3）的比值呈正相关，与芳香度呈负相关。富里酸组分的芳香度与 E2/E3 之间也存在高度正相关关系。使用极性逐渐降低的洗脱剂可以提供更简单的土壤和水生富里酸组分。
