The methyl viologen incorporated zeolite modified carbon paste electrode—part 1. Electrochemical behaviour in aqueous media. Effects of supporting electrolyte and immersion time

Walcarius, Alain; Lamberts, L.; Derouane, Éric G.

doi:10.1016/0013-4686(93)80107-b

Cited by 80 publications

(49 citation statements)

References 31 publications

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“…Smaller enhancements have been, however, observed for the preconcentration analysis of the negatively charged chloro-complexes of Hg II at electrodes modified with protonated APS samples, although kinetic experiments performed on batch suspensions had revealed much faster access of Hg II to the ion exchange sites within ordered structures than in amorphous protonated APS samples. This rather surprising result was interpreted on the basis of the hydrophilic character of protonated APS particles that aggregate during the preparation of the carbon paste electrode (contrarily to MPS samples that are more uniformly dispersed within the hydrophobic matrix), similarily to what was observed with zeolite modified carbon paste electrodes [60]. In this case, solution penetration into mm-thick regions of the paste implies that mass transport is mainly governed by interparticle diffusion rather than intraparticle diffusion, weakening therefore the beneficial effect of an ordered internal structure.…”

Section: Voltammetry After Accumulation At Open Circuitsupporting

confidence: 58%

Grafted Silicas in Electroanalysis: Amorphous Versus Ordered Mesoporous Materials

et al. 2003

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This work reports the enhanced response of electrodes modified with ordered mesoporous silica-based materials, as compared to corresponding amorphous materials, in case of open-circuit accumulation and voltammetric detection of a target analyte. Several porous silica samples grafted with either thiol or ammonium groups, displaying high surface areas with various structural characteristics and different pore sizes, have been examined with respect to their ability to concentrate Hg II species. Better accessibility to the binding sites and faster diffusion processes in the interior of grafted silicas have been observed for the ordered samples prepared by micelle-templating because they contain channels of regular size, which are less tortuous than the irregular pore systems in amorphous materials. When applied in electrochemical detection of Hg II after preconcentration, the ordered solids gave rise to voltammetric signals higher by more than one order of magnitude in comparison to the amorphous organically-modified silicas. This rather new class of materials, which can be easily produced as ordered organic-inorganic hybrids, is expected to improve the performance of silica-modified electrodes in various fields of electroanalysis.

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Section: Voltammetry After Accumulation At Open Circuitsupporting

confidence: 58%

Grafted Silicas in Electroanalysis: Amorphous Versus Ordered Mesoporous Materials

et al. 2003

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“…This was ascertained by re-oxidizing the metallic copper deposit, in an anodic stripping scan, after 25 successive¯ow injection experiments. Unlike the behavior of this electrode in electrolytic medium [7], however, the hydrodynamic voltammogram observed here did not level off when decreasing potentials below À0.5 V, but peak currents were found to increase continuously with a slope almost parallel to those obtained at the undoped NaY-ZMCPE, in agreement with the Ohm's Law. It is also noteworthy that the current jump observed around À0.4 V was spread compared to that in electrolytic medium because of the high ohmic drop induced by the absence of conducting species…”

Section: Flow Injection Response and Regeneration Proceduressupporting

confidence: 75%

“…Both the time for the regeneration solution to contact the electrode surface and the concentration of the reagent, Cu 2 (or Ag ), were optimized. It was found that carrying a 5 Â 10 À5 M Cu 2 (or Ag ) solution during one minute was the best compromise for ascertaining the completion of the ion exchange process and avoiding signi®cant percolation of this solution in the bulk paste, which is known to occur at ZMCPEs [7]. The water¯ow was then set up again and the ®rst new injection was only performed after a 2-min delay which was required to clean the¯owing device from any remaining trace of copper (washing step).…”

Section: Flow Injection Response and Regeneration Proceduresmentioning

confidence: 99%

Amperometric Detection of Nonelectroactive Cations in Electrolyte-Free Flow Systems at Zeolite Modified Electrodes

Walcarius¹,

Mariaulle

Louis

et al. 1999

Electroanalysis

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An electrochemical detector was designed and constructed, based upon a thin-layer cell with a working electrode prepared from carbon paste modi®ed with copper-(or silver-) exchanged zeolite particles. This electrode was then evaluated as a sensor for nonelectroactive cations in an electrolyte-free¯ow injection system and as an amperometric detector for suppressed ion chromatography. In the absence of supporting electrolyte, a higher signal-to-background ratio enhanced by about two order of magnitude the response obtained in electrolytic medium. Peak currents resulted from an important faradic component which was due to the electrochemical activity of the mediatorcontaining zeolites, while the capacitive counterpart was much lower. When applied to the analysis of alkali, alkaline earth metal and ammonium ions, in combination with a suppressed ion chromatography system, the zeolite-modi®ed detector gave rise to reproducible amperometric responses. This resulted in chromatograms comparable to those obtained simultaneously by using a conductivity detector in series, and any extra-column effects were never observed. The most sensitive responses were achieved when using zeolites displaying the largest pore size, the highest ion exchange capacity, and the most mobile mediator, to ensure the highest exchange rates for the analytes within the zeolite framework.

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“…The most significant advantage is the possibility of reuse and introduction of a clean technology decreasing the cost of the catalyzed process [2]. An important heterogeneous catalyst currently available is zeolite, which has received great attention in the catalysis field [3,4]. The majority of zeolites are formed from silicon and aluminum atoms in various Al/Si ratios linked through tetrahedral oxygen atoms [5].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Behavior of Copper Porphyrin Synthesized into Zeolite Cavity: A Sensor for Hydrazine

et al. 1998

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The copper tetraphenylporphyrin (CuTPP) was prepared within a NaY zeolite cavity to investigate the electrocatalytic behavior of CuTPP upon the oxidation of hydrazine and cysteine. The amount of 0.067 mmol g ¹1 of CuTPP was obtained in the zeolite cavities. Cyclic voltammetry showed only an anodic peak at 320 mV that was assigned to the oxidation of Cu I to Cu II . This peak was not affected by the supporting electrolyte nature or by solution pH. The electrode showed electrocatalytic activity to oxidize both cysteine and hydrazine, however for cysteine the activity was weak, possibly as a result of the adsorption of oxidation product (cystine). Although hydrazine oxidation was efficient, neither oxidation was diffusion controlled. A linear correlation between catalytic current and hydrazine concentration allows sensing of hydrazine in the 0.2 × 10 ¹6 to 1.0 × 10 ¹6 mol L ¹1 concentration range. The detection limit was 1.0 × 10 ¹7 mol L ¹1, and the response time was 1.1 s. The sensor was stable for at least 6 months under continuous use.

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The methyl viologen incorporated zeolite modified carbon paste electrode—part 1. Electrochemical behaviour in aqueous media. Effects of supporting electrolyte and immersion time

Cited by 80 publications

References 31 publications

Grafted Silicas in Electroanalysis: Amorphous Versus Ordered Mesoporous Materials

Grafted Silicas in Electroanalysis: Amorphous Versus Ordered Mesoporous Materials

Amperometric Detection of Nonelectroactive Cations in Electrolyte-Free Flow Systems at Zeolite Modified Electrodes

Electrochemical Behavior of Copper Porphyrin Synthesized into Zeolite Cavity: A Sensor for Hydrazine

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