The influence of 4-mercaptopyridine layer instability on rapid electron transfer reaction

Lima‐Neto, Pedro de; Parente, Marcelo Monteiro Valente; Moreira, Ícaro S.; Diógenes, Izaura C.N.; Mattos, O.R.; Barcia, Oswaldo E.; Santos, Ricardo; Freire, V. N.

doi:10.1016/j.jelechem.2008.03.006

Cited by 6 publications

(4 citation statements)

References 26 publications

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“…For the pyS SAM, this plot was not constructed due to the instability of this monolayer, which decomposes to give adsorbed elemental sulfur on gold thereby inactivating the surface for assessment of the protein hET reaction. 29,38,49,51,54 In relation to the terminal (solution facing) end of the SAMs, the CVs obtained with mixed SAMs of Hpyt and POT (Figure 1C) clearly show that the presence of the pyridyl N atom is conditional for the ET reaction of Cyt c in solution since for the homogeneous SAM of POT (solid blue line) no peaks are observed in the CV. The mixed SAMs were prepared by immersing the gold electrodes in solutions containing various mixtures of Hpyt and POT assuming that the mole fraction on the surface correlates to that in solution.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…In addition, no redox process was observed when the modified electrodes were transferred to an electrochemical cell containing only the electrolyte solution, suggesting that the protein is not adsorbed to the SAMs. For the pyS SAM, this plot was not constructed due to the instability of this monolayer, which decomposes to give adsorbed elemental sulfur on gold thereby inactivating the surface for assessment of the protein hET reaction. ,,,, …”

Section: Resultsmentioning

confidence: 99%

“…The modification of the gold quartz crystals with TNA, iTNA, Hpyt, and pyS species was carried out as described in the literature. ,,− For the QCM measurements, first the gold sensors were modified by immersion in 1.0 × 10 –4 mol L –1 aqueous solutions of the sulfur compounds for 30 min. After that, the modified gold sensors were washed, rinsed, and immersed in the cell containing 0.1 mol L –1 PBS.…”

Section: Methodsmentioning

confidence: 99%

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Electrochemistry, Surface Plasmon Resonance, and Quartz Crystal Microbalance: An Associative Study on Cytochrome c Adsorption on Pyridine Tail-Group Monolayers on Gold

et al. 2013

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Quartz crystal microbalance (QCM), surface plasmon resonance (SPR), and electrochemistry techniques were used to study the electron-transfer (ET) reaction of cytochrome c (Cyt c) on gold surfaces modified with thionicotinamide, thioisonicotinamide, 4-mercaptopyridine, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 5-phenyl-1,3,4-oxadiazole-2-thiol, 4,4'-bipyridine, and 4,4'-dithiopyridine. The electrochemical results showed that the ET process is complex, being chiefly diffusional with steps depending on the orientation of the pyridine or phenyl tail group of the modifiers. The correlation between the electrochemical results and those acquired by SPR and QCM indicated the presence of an adlayer of Cyt c adsorbed on the thiolate SAMs. This adlayer, although being not electroactive, is essential to assess the ET reaction of Cyt c in solution. The results presented in this work are consistent with the statement (Feng, Z. Q.; Imabayashi, S.; Kakiuchi, T.; Niki, K. J. Electroanal. Chem. 1995, 394, 149-154) that the ET reaction of Cyt c can be explained in terms of the through-bond tunneling mechanism.

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Section: ■ Results and Discussionmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Electrochemistry, Surface Plasmon Resonance, and Quartz Crystal Microbalance: An Associative Study on Cytochrome c Adsorption on Pyridine Tail-Group Monolayers on Gold

et al. 2013

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“…Using the EIS data obtained in the presence of redox couple [Fe(CN) 6 ] 3-/4− , it was possible to estimate the apparent rate constant, which can be expressed by equation 1. 28…”

Section: B147mentioning

confidence: 99%

Mixed Self-Assembled Monolayers of Mercaptoundecanoic Acid and Thiolactic Acid for the Construction of an Enzymatic Biosensor for Hydroquinone Determination

Mossanha

Ramos

Santos

et al. 2015

J. Electrochem. Soc.

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A horseradish peroxidase (HRP) biosensor was constructed using binary self-assembled monolayers (SAM) of 11-mercaptoundecanoic acid (MUA) and thiolactic acid (TLA) on gold surface. The advantages of using mixed SAM for the enzyme immobilization is that the long carbon chain molecules act as a support for the enzyme while the short chain molecules favor the electron transfer process. In order to obtain this modified surface, the gold electrode was incubated in a solution containing different proportions of MUA and TLA and the best concentration ratio of these molecules was 0.5 and 1.0 mmol L −1 , respectively. The preparation steps and the biosensor response were monitored by electrochemical techniques. The biosensor proposed was applied to determine hydroquinone in a 0.10 mol L −1 phosphate buffer solution containing H 2 O 2 0.3 mmol L −1 . The Au-SAM mix -HRP electrode, in the presence of hydrogen peroxide, catalyzes the oxidation of hydroquinone to the corresponding quinone, which is electrochemically reduced back to hydroquinone at −0.08 V vs Ag/AgCl. The analytical curve was linear for hydroquinone concentrations from 5.0 to 30 μmol L −1 and the detection limit was 1.26 μmol L −1 . The lifetime of this biosensor was 15 days. The modified electrode displayed good reproducibility, sensitivity and stability for the determination of hydroquinone.The modification of electrode surfaces using the self-assembled monolayers (SAM) technique is more convenient, because they form spontaneously, easy to handle mechanically and relatively stable in electrolyte solutions. 1 The main interest in developing mixed selfassembled monolayers (SAM mix ) is related to the development of attractive methods to promote different arrangements on the electrode surface, which enables the control of specific reaction sites. In this way, SAM mix can be configured as an appropriate platform for the immobilization of biomolecules 2 which have been frequently applied in electroanalysis for the development of biosensors, 3,4 since well-organized and compact monolayers present advantages like selectivity, sensitivity and reduced overpotentials in electrocatalytic reactions. The SAM mix can be obtained by combining the properties of alkanethiols with different carbon chain lengths or different functional group. 5 Several methods for the preparation of mixed SAMs are reported in the literature, being the most commonly used the coadsorption of different thiols, 6,7 and also by electrochemical substitution modification. 8,9 The SAM mix obtained through co-adsorption of different functional groups was described by Ngunjiri et al, 10 formed by molecules octadecanethiol and 11-mercaptoundecanoic acid for immobilization of proteins. Another example, Ji et al. 11 developed the SAM mix formed by thioctic acid (T-COOH) and thioctic acid amide (T-NH 2 ) which was used to immobilize tyrosinase to construct an electrochemical biosensor for phenolic compounds. Studies with this biosensor showed that mixed SAMs improved protein adsorption and they were more co...

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Thionicotinamide SAM on Gold: Adsorption Studies and Electroactivity

et al. 2009

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STM and impedance results of the self-assembled monolayer (SAM) formed with thionicotinamide (TNA) on gold indicate the presence of defects that increase with the immersion time of the electrode in the TNA solution affecting the SAM electroactivity toward the electron transfer reaction of the cytochrome c metalloprotein and [Fe(CN) 6 ] 4À and [Ru(NH 3 ) 6 ] 3þ complexes. It was observed that this electroactivity was also affected by the pH of the electrolyte solution. SERS and STM data indicate sulfur coordination to the surface with contribution of the NH 2 group. From the dependence of the TNA surface coverage on the temperature and concentration in solution, thermodynamic parameters of adsorption were determined.

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The influence of 4-mercaptopyridine layer instability on rapid electron transfer reaction

Cited by 6 publications

References 26 publications

Electrochemistry, Surface Plasmon Resonance, and Quartz Crystal Microbalance: An Associative Study on Cytochrome c Adsorption on Pyridine Tail-Group Monolayers on Gold

Electrochemistry, Surface Plasmon Resonance, and Quartz Crystal Microbalance: An Associative Study on Cytochrome c Adsorption on Pyridine Tail-Group Monolayers on Gold

Mixed Self-Assembled Monolayers of Mercaptoundecanoic Acid and Thiolactic Acid for the Construction of an Enzymatic Biosensor for Hydroquinone Determination

Thionicotinamide SAM on Gold: Adsorption Studies and Electroactivity

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