Binding of Hg2+ with Phytochelatins: Study by Differential Pulse Voltammetry on Rotating Au-Disk Electrode, Electrospray Ionization Mass-Spectrometry, and Isothermal Titration Calorimetry

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• 作者：Elena Chekmeneva ; Jos Manuel Daz-Cruz ; Cristina Ario ; Miquel Esteban
• 刊名：Environmental Science & Technology
• 出版年：2009
• 出版时间：September 15, 2009
• 年：2009
• 卷：43
• 期：18
• 页码：7010-7015
• 全文大小：247K
• 年卷期：v.43,no.18(September 15, 2009)
• ISSN：1520-5851

文摘

The binding of Hg²⁺ with synthetic phytochelatins ((γ-Glu-Cys)_n-Gly, PC_n, n = 2, 3, 4) was investigated by a recently proposed electroanalytical method, using differential pulse voltammetry on the rotating Au-disk electrode, Electrospray ionization mass-spectrometry (ESI-MS) and isothermal titration calorimetry (ITC). ESI-MS experiments provided the exact stoichiometries of the complexes formed at different PC_n/Hg²⁺ ratios. Voltammetry provided more detailed information on the complexation processes through the use of multivariate curve resolution by alternating least squares of the data matrix obtained from titrations with fine increments of metal or ligand. The system Hg²⁺-GSH-PC₂ was investigated by voltammetry in order to obtain an estimation of the Hg²⁺ behavior in the presence of two related ligands. The additional assessment of the stability of Hg²⁺-PC_n complexes was achieved through ITC by using the therapeutic chelator sodium 2,3-dimercaptopropanesulfate (DMPS) over Hg²⁺-PC_n systems. The stability of various Hg²⁺-PC_n complexes and the ability of DMPS to replace PC_n from these complexes were examined.