Molar absorption coefficients and stability constants of Zincon metal complexes for determination of metal ions and bioinorganic applications
Molar absorption coefficients and stability constants of Zincon metal complexes for determination of metal ions and bioinorganic applications
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DOI：
10.1016/j.jinorgbio.2017.08.006
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发表时间：
2017-11-01
影响因子：
3.9
通讯作者：
Krezel, Artur
中科院分区：
文献类型：
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作者：
Kocyla, Anna;Pomorski, Adam;Krezel, Artur
锌试剂(ZI)是测定锌、铜离子最常用的发色络合探针之一。众所周知，它还能与其他金属离子结合。然而，关于其结合性能和摩尔吸收系数的文献数据相当差，在不同的出版物中不同，或仅在某些条件下确定。目前还没有在不同条件下对锌、铜与锌的亲和力进行系统的研究。然而，这种商业上广泛可用的廉价试剂经常是测量金属结合和释放以及测定其他感兴趣的配体/大分子的亲和常数的首选探针。在此，我们研究了锌及其与锌、铜、镉、汞、钴、镍和铅的络合物在6-9.9范围内的光谱性质和稳定性。结果表明，在水溶液中以MZI络合物为主，但在Co2+和Ni2+中也有M(Zi)(2)络合物生成。在pH 7.4时，ZNZI络合物在618 nm处的摩尔吸收系数为24200，CuZI络合物在599 nm处的摩尔吸光系数为26100M-1 cm(-1)。它们的离解常数分别为2.09×10~(-6)和4.68×10~(-1)~(-1)M。我们的结果提供了新的和重新评估的光学和稳定性数据，适用于广泛的化学和生物无机应用，包括金属离子检测和感兴趣的配体的定量和亲和力研究。简介：为快速定量金属离子提供了准确的锌试剂与锌、镉、汞、钴、镍、铜和铅的络合物的摩尔吸收系数。在较宽的pH范围内测定了锌试剂与锌、铜的稳定常数。
Zincon (ZI) is one of the most common chromophoric chelating probes for the determination of Zn2+ and Cu2+ ions. It is also known to bind other metal ions. However, literature data on its binding properties and molar absorption coefficients are rather poor, varying among publications or determined only in certain conditions. There are no systematic studies on Zn2+ and Cu2+ affinities towards ZI performed under various conditions. However, this widely commercially available and inexpensive agent is frequently the first choice probe for the measurement of metal binding and release as well as determination of affinity constants of other ligands/macromolecules of interest. Here, we establish the spectral properties and the stability of ZI and its complexes with Zn2+, Cu2+, Cd2+, Hg2+,Co2+, Ni2+ and Pb2+ at multiple pH values from 6 to 9.9. The obtained results show that in water solution the MZI complex is predominant, but in the case of Co2+ and Ni2+, M(ZI)(2) complexes are also formed. The molar absorption coefficient at 618 nm for ZnZI and 599 nm for CuZI complexes at pH 7.4 in buffered (I = 0.1 M) water solutions are 24,200 and 26,100 M-1 cm(-1), respectively. Dissociation constants of those complexes are 2.09 x 10(-6) and 4.68 x 10(-1)7 M. We also characterized the metal-assisted Zincon decomposition. Our results provide new and reassessed optical and stability data that are applicable to a wide range of chemical and bioinorganic applications including metal ion detection, and quantification and affinity studies of ligands of interest.Synopsis: Accurate values of molar absorption coefficients of Zincon complex with Zn2+, Cd2+, Hg2+, Co2+, Ni2+, Cu2+, and Pb2+ for rapid metal ion quantification are provided. Zincon stability constants with Zn2+ and Cu2+ in a wide pH range were determined.