Six hydrophobic and hydrophilic fractions were isolated using XAD-8 and XAD-4 resins, and were extensively characterized. Partition coefficients of perylene, pbenanthrene and anthracene binding to the six fractions we...Six hydrophobic and hydrophilic fractions were isolated using XAD-8 and XAD-4 resins, and were extensively characterized. Partition coefficients of perylene, pbenanthrene and anthracene binding to the six fractions were determined by fluorescence quenching titration. The Kdo~ values obtained for the polycyclic aromatic hydrocarbons （PAHs） binding to the hydrophobic fractions were larger than those to the hydrophilic fractions. Nonlinear Stem-Volmer plots were observed when binding phenanthrene and anthracene to some hydrophilic fraction samples, suggesting saturation of polar interaction binding sites. A significant correlation of logKdo~ values with molecular weights and molar absorptivities at 280 nm was observed, while atomic ratio of C/t-I was found to be a poor indicator for aromaticity. Other structural descriptors such as paraffinic carbon and polarity influenced the DOM-fraction ability to bind PAHs. Different interaction mechanisms underlying binding of the different fractions to the PAHs were also discussed.展开更多
基金supported by the National Basic Research Program (973) of China (No. 2008CB418200)the National Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-yw-102)the National Natural Science Foundation of China (No.40525011, 40632011)
文摘Six hydrophobic and hydrophilic fractions were isolated using XAD-8 and XAD-4 resins, and were extensively characterized. Partition coefficients of perylene, pbenanthrene and anthracene binding to the six fractions were determined by fluorescence quenching titration. The Kdo~ values obtained for the polycyclic aromatic hydrocarbons （PAHs） binding to the hydrophobic fractions were larger than those to the hydrophilic fractions. Nonlinear Stem-Volmer plots were observed when binding phenanthrene and anthracene to some hydrophilic fraction samples, suggesting saturation of polar interaction binding sites. A significant correlation of logKdo~ values with molecular weights and molar absorptivities at 280 nm was observed, while atomic ratio of C/t-I was found to be a poor indicator for aromaticity. Other structural descriptors such as paraffinic carbon and polarity influenced the DOM-fraction ability to bind PAHs. Different interaction mechanisms underlying binding of the different fractions to the PAHs were also discussed.
