Faculty of Environmental Science & Engineering, Kunming University of Science & Technology, Kunming 650093, China.
Environ Pollut. 2012 Feb;161:76-82. doi: 10.1016/j.envpol.2011.09.040. Epub 2011 Nov 2.
Dialysis equilibrium system was applied to investigate the roles of Cu(II) and Mg(II) on DOM-ofloxacin (OFL) interaction. The binding behavior of both cations and OFL were studied. The introduction of Cu(II) increased DOM-OFL interaction, while Mg(II) decreased DOM-OFL binding. Cu(II) binding to DOM was also increased by OFL, while Mg(II) binding was decreased by OFL. The change in OFL binding amount in the absence and presence of cations (ΔC(b)) was calculated and compared with cation binding (C(b)(m)). ΔC(b)/C(b)(m) was in the range of 1-3 for Cu(II) depending on the applied Cu concentration. Two ternary complexes of DOM-OFL-Cu and DOM-Cu-OFL were proposed. For Mg(II), ΔC(b)/C(b)(m) was around -1 at Mg(II) concentrations lower than 1 mM, but decreased up to -5 with increasing Mg(II) concentration. The competitive effect of Mg(II) to OFL was thus proposed. FTIR spectra were collected for mechanistic discussion.
透析平衡系统被应用于研究 Cu(II) 和 Mg(II) 在 DOM-氧氟沙星（OFL）相互作用中的作用。研究了两种阳离子和 OFL 的结合行为。Cu(II)的引入增加了 DOM-OFL 的相互作用，而 Mg(II)则降低了 DOM-OFL 的结合。OFL 的引入也增加了 DOM 与 Cu(II)的结合，而 OFL 的引入则降低了 Mg(II)与 DOM 的结合。计算并比较了无阳离子和有阳离子时（ΔC(b)）OFL 结合量的变化（ΔC(b)/C(b)(m)）。ΔC(b)/C(b)(m)在 Cu(II)浓度为 1-3 之间，取决于应用的 Cu 浓度。提出了 DOM-OFL-Cu 和 DOM-Cu-OFL 两种三元配合物。对于 Mg(II)，在 Mg(II)浓度低于 1mM 时，ΔC(b)/C(b)(m)约为-1，但随着 Mg(II)浓度的增加，其值降低至-5。因此，提出了 Mg(II)对 OFL 的竞争效应。收集了傅里叶变换红外（FTIR）光谱进行机理讨论。
