Influence of the HEPES Buffer on Electrochemical Reaction of the Copper(II)-Salicylaldoxime Complex

́, Vlado Cuculic; Mlakar, Marina; Branica, Marko

doi:10.1002/(sici)1521-4109(199809)10:12<852::aid-elan852>3.3.co;2-f

Cited by 4 publications

(5 citation statements)

References 11 publications

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“…We hypothesize the Pu and Bk reduction likely resulted from radiolysis provided by the high-energy X-ray beam. In addition, sulfonic acid buffers -the matrices in which these measurements were collected -are known to enhance or facilitate redox activity (Cuculic ´et al, 1998), yet it should be noted that reductive decomposition of Pu and Bk was also observed in other buffers (i.e. TRIS buffer).…”

Section: Discussionmentioning

confidence: 99%

In situ beam reduction of Pu(IV) and Bk(IV) as a route to trivalent transuranic coordination complexes with hydroxypyridinone chelators

Carter¹,

Wacker²,

Smith³

et al. 2022

J Synchrotron Radiat

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The solution-state interactions of plutonium and berkelium with the octadentate chelator 3,4,3-LI(1,2-HOPO) (343-HOPO) were investigated and characterized by X-ray absorption spectroscopy, which revealed in situ reductive decomposition of the tetravalent species of both actinide metals to yield Pu(III) and Bk(III) coordination complexes. X-ray absorption near-edge structure (XANES) measurements were the first indication of in situ synchrotron redox chemistry as the Pu threshold and white-line position energies for Pu-343-HOPO were in good agreement with known diagnostic Pu(III) species, whereas Bk-343-HOPO results were found to mirror the XANES behavior of Bk(III)-DTPA. Extended X-ray absorption fine structure results revealed An—OHOPO bond distances of 2.498 (5) and 2.415 (2) Å for Pu and Bk, respectively, which match well with bond distances obtained for trivalent actinides and 343-HOPO via density functional theory calculations. Pu(III)- and Bk(III)-343-HOPO data also provide initial insight into actinide periodicity as they can be compared with previous results with Am(III)-, Cm(III)-, Cf(III)-, and Es(III)-343-HOPO, which indicate there is likely an increase in 5f covalency and heterogeneity across the actinide series.

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Section: Discussionmentioning

confidence: 99%

In situ beam reduction of Pu(IV) and Bk(IV) as a route to trivalent transuranic coordination complexes with hydroxypyridinone chelators

Carter¹,

Wacker²,

Smith³

et al. 2022

J Synchrotron Radiat

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“…Both HEPES and TES increased the baseline current by about one order of magnitude (from~0.65 µA tõ 6.5 µA). Both were reported to be electrochemically active and would interfere with the electrochemical characterizations (Ahmed et al, 2016;Cuculić et al, 1998). Moreover, these buffers could also interact with ions in the growth medium and biologic components (e.g., DNA and cell membrane lipid) as comprehensively discussed by Ferreira et al (2015).…”

Section: Shieldingmentioning

confidence: 99%

Technical‐scale biophotovoltaics for long‐term photo‐current generation from Synechocystis sp. PCC6803

Lai

Schneider

Tschörtner

et al. 2021

Biotech & Bioengineering

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A carbon-free energy supply is essential to sustain our future. Biophotovoltaics (BPV) provides a promising solution for hydrogen supply by directly coupling light-driven water splitting to hydrogen formation using oxygenic photoautotrophic cyanobacteria. However, BPV is currently limited by its low photon-to-current efficiency, and current experimental setups at a miniaturized scale hinder the rational investigation of the process and thus system optimization. In this article, we developed and optimized a new technical-scale (~250 ml working volume) BPV platform with defined and controllable operating parameters. Factors that interfered with reproducible and stable current output signals were identified and adapted. We found that the classical BG11 medium, used for the cultivation of cyanobacteria and also in many BPV studies, caused severe interferences in the bioelectrochemical experiments. An optimized nBG11 medium guaranteed a low and stable background current in the BPV reactor, regardless of the presence of light and/or mediators. As proof-of-principle, a very high long-term light-dependent current output (peak current of over 20 µA) was demonstrated in the new set-up over 12 days with living Synechocystis sp. PCC6803 cells and validated with appropriate controls. These results report the first reliable BPV platform generating reproducible photocurrent while still allowing quantitative investigation, rational optimization, and scale-up of BPV processes.

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“…In this study, we carefully examined the electrochemical properties of Au, Pt, and GC electrodes in three biological buffers, namely Tris, phosphate, and HEPES. 35,36 This study specifically focused on how ions, pH values, and the redox phenomenon on electrode surfaces affect the electrochemical windows of the three electrodes. By mixing the solution with HCl, H 2 SO 4 , and NaOH solutions, we were able to adjust their pH values from 6.0 to 9.0, allowing us to illustrate the effects of pH levels and type of ions involved.…”

Section: ■ Introductionmentioning

confidence: 99%

Revisiting Background Signals and the Electrochemical Windows of Au, Pt, and GC Electrodes in Biological Buffers

Lai

Luo

2019

ACS Appl. Energy Mater.

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For electrochemical experiments involving biological buffers, pH values, ions, and electrode materials play major roles in the electrochemical readout of the measurements. When conducting electrochemical experiments, background signals are sometimes mixed with true signals, easily leading to a wrong interpretation of the data. These background signals are easily induced by the reactions between buffers and electrode materials. However, these background signals have rarely been studied systematically. In response to rapid developments in the field and application of bioelectrodes, we conducted a much-needed systematic study of these background signals and the electrochemical windows in buffersspecifically, of the electrochemical windows gold, glassy carbon, and platinum in three most commonly used biological buffers, namely, Tris, HEPES, and phosphate. We examined the pH effect using HCl, H2SO4, and NaOH to modulate the pH values from 6.0 to 9.0 in the three buffers. Furthermore, through comparison of HCl and H2SO4, we were able to illustrate the reaction between Cl– ions and the metallic electrode. This reaction also led to clear redox peaks as background signals in cyclic voltammograms. When a high potential was applied, the formation of hydroxide was evident on the metallic electrode, which led to a clear reduction peak in cyclic voltammograms. In addition, we used an atomic force microscope to monitor the morphology of the electrode surface when a cyclic potential was applied. All tests were conducted in the presence of 100 mM LiClO4, which was used as the electrolytes. These characterization results yield critical insights into electrode surface reactions, insights which are crucial for precisely interpreting electrochemical results measured in biological buffers. This fundamental study provides comprehensive information, which is especially helpful for the development of bioelectrode materials and bioelectronics applications.

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Influence of the HEPES Buffer on Electrochemical Reaction of the Copper(II)-Salicylaldoxime Complex

Cited by 4 publications

References 11 publications

In situ beam reduction of Pu(IV) and Bk(IV) as a route to trivalent transuranic coordination complexes with hydroxypyridinone chelators

In situ beam reduction of Pu(IV) and Bk(IV) as a route to trivalent transuranic coordination complexes with hydroxypyridinone chelators

Technical‐scale biophotovoltaics for long‐term photo‐current generation from Synechocystis sp. PCC6803

Revisiting Background Signals and the Electrochemical Windows of Au, Pt, and GC Electrodes in Biological Buffers

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