ALUMINUM SPECIATION USING MORIN .1. MORIN AND ITS COMPLEXES WITH ALUMINUM
ALUMINUM SPECIATION USING MORIN .1. MORIN AND ITS COMPLEXES WITH ALUMINUM
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DOI：
10.2134/jeq1990.00472425001900010008x
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发表时间：
1990-01-01
影响因子：
2.4
通讯作者：
DRISCOLL, CT
中科院分区：
文献类型：
--
作者：
BROWNE, BA;MCCOLL, JG;DRISCOLL, CT
在这项研究和同伴的研究中，我们开发了一种程序，使用荧光螯合剂桑色素（2，3，4，5，7-五羟基黄酮），在酸性pH范围内的水溶液中形成铝。桑色素是具有五个弱活性官能团的五元酸。然而，只有第一个质子解离反应被发现是显着的酸性pH值范围内，和一个简单的单质子模型（pKa 1 = 5.04）准确地描述了光子结合。铝和桑色素形成1：1和1：2和/或1：3（Al/桑色素）化学计量的络合物，但在低的桑色素总浓度（接近1 μ M）下，仅1：1种类是普遍的。1：1铝/桑色素复合物在酸性pH范围内的平衡化学密切描述的抛物线模型与三个复合物的形成一致：AlH 4 MOR 2+，Al（OH）H4 MOR+，和Al（OH）2 H4 MOR 0。对于Al和六种可能的干扰阳离子，在酸性pH范围内，桑色素相对于Al的亲和力顺序大致如下：Al > Fe（III）> Cu > Fe（II）> Ca > Mg > Mn = Zn。竞争阳离子桑色素复合物的形成增强pH值的增加。没有测试的阳离子形成复合物与桑色素荧光光谱重叠的铝-桑色素复合物的光谱。
In this and a companion study, we developed a procedure that uses the fluorescing chelating agent morin (2,3,4,5,7-pentahydroxy-flavone) to speciate aqueous Al in the acidic pH range. Morin is a pentaprotic acid with five weakly active functional groups. However, only the first proton dissociation reaction was found to be significant in the acidic pH range, and a simple monoprotic model (pKa1 = 5.04) accurately described photon binding. Aluminum and morin formed complexes of 1:1 and 1:2 and/or 1:3 (Al/morin) stoichiometry, but at low total morin concentrations (near 1 .mu.M) only 1:1 species were prevalent. The equilibrium chemistry of 1:1 Al/morin complexes in the acidic pH range was closely described by a parabolic model consistent with the formation of three complexes: AlH4MOR2+, Al(OH)H4MOR+, and Al(OH)2H4MOR0. For Al and six potentially interferring cations, the order of affinity for morin relative to Al in the acidic pH range was approximately as follows: Al > Fe(III) > Cu > Fe(II) > Ca > Mg > Mn = Zn. Formation of competing cation-morin complexes was enhanced with increasing pH. None of the tested cations formed complexes with morin with fluorescence spectra overlapping the spectra of the Al-morin complexes.