Determination of the Side-Reaction Coefficient of Desferrioxamine B in Trace-Metal-Free Seawater
Determination of the Side-Reaction Coefficient of Desferrioxamine B in Trace-Metal-Free Seawater
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去铁胺B在无痕量金属海水中副反应系数的测定
DOI：
10.3389/fmars.2016.00117
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发表时间：
2016
影响因子：
3.7
通讯作者：
S. M. Burns
中科院分区：
文献类型：
--
作者：
J. Schijf;S. M. Burns
电化学技术，如竞争性配体平衡吸附阴极溶出伏安法（ACSV-CLE）可以确定海洋有机配体的总浓度和它们对特定金属的条件结合常数，但不能识别它们。从微生物培养物中分离或通过基因组学生物合成的单个有机配体可以通过NMR和串联MS分析进行结构表征，但这是繁琐和耗时的。一个互补的方法是比较天然配体的已知特性，特别是它们的条件结合常数，与那些在合适的条件下测量的模型有机配体。这种比较不能有意义地解释，除非模型配体在海水中的副反应系数（SRC）进行了彻底的评估。我们进行了一系列的电位滴定，在非配位介质中，在海水离子强度（0.7 M NaClO 4）的金属：配体摩尔比的范围内，研究络合的铁载体去铁胺B（DFO B）与镁和钙，它具有最高的亲和力之间的主要海盐阳离子。根据在不存在和存在甲磺酸盐（甲磺酸盐）的情况下对乙酰异羟肟酸进行的类似滴定，确定Mg和Ca与这种常见DFOB反离子的结合强度不足以干扰DFOB滴定。所有DFOB络合物与镁和钙，包括，第一次，双齿配合物的稳定常数进行了测定。没有发现镁和钙与DFOB末端胺配位的证据。从改进的DFOB形态，我们计算了五个SRC的每一个（去）质子化形式的DFOB在痕量金属-无海水，但我们也提出了一个更方便的定义，允许调整所有的DFOB稳定常数的海水条件下，无论这些形式被选为“组件”（参考物种）。在海水中含有DFOB的镉形态的一个例子说明了不同的SRC的多质子，多齿有机配体的非平凡的使用。
Electrochemical techniques like adsorptive cathodic stripping voltammetry with competitive ligand equilibration (ACSV-CLE) can determine total concentrations of marine organic ligands and their conditional binding constants for specific metals, but cannot identify them. Individual organic ligands, isolated from microbial cultures or biosynthesized through genomics, can be structurally characterized via NMR and tandem MS analysis, but this is tedious and time-consuming. A complementary approach is to compare known properties of natural ligands, particularly their conditional binding constants, with those of model organic ligands, measured under suitable conditions. Such comparisons cannot be meaningfully interpreted unless the side-reaction coefficient (SRC) of the model ligand in seawater is thoroughly evaluated. We conducted series of potentiometric titrations, in non-coordinating medium at seawater ionic strength (0.7 M NaClO4) over a range of metal:ligand molar ratios, to study complexation of the siderophore desferrioxamine B (DFOB) with Mg and Ca, for which it has the highest affinity among the major seasalt cations. From similar titrations of acetohydroxamic acid in the absence and presence of methanesulfonate (mesylate), it was determined that Mg and Ca binding to this common DFOB counter-ion is not strong enough to interfere with the DFOB titrations. Stability constants were measured for all DFOB complexes with Mg and Ca including, for the first time, the bidentate complexes. No evidence was found for Mg and Ca coordination with the DFOB terminal amine. From the improved DFOB speciation, we calculated five SRCs for each of the five (de)protonated forms of DFOB in trace-metal-free seawater, yet we also present a more convenient definition of a single SRC that allows adjustment of all DFOB stability constants to seawater conditions, no matter which of these forms is selected as the 'component' (reference species). An example of Cd speciation in seawater containing DFOB illustrates the non-trivial use of different SRCs for polyprotic, polydentate organic ligands.
影响因子：
56.9
作者：
Martinez, JS;Zhang, GP;Butler, A
通讯作者：
Butler, A
无机Mn和Mn去铁胺B与海水中O2、O2(-)和H2O2的反应性
影响因子：
11.4
作者：
Wuttig;M. I. Heller;P. L. Croot
通讯作者：
P. L. Croot