A solid polymer electrolyte amperometric detector for FIA and HPLC with mobile phases of low conductivity

Loub, Lukáš; Opekar, František; Pacáková, Věra; Štulı́k, Karel

doi:10.1002/elan.1140040410

Cited by 12 publications

(4 citation statements)

References 10 publications

(3 reference statements)

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“…This has already been advantage of in analyses with flow-through electrochemical detection cells [17,18]. The low current encountered and.…”

Section: Lwroductionmentioning

confidence: 97%

Detection of electroinactive ions using conducting polymer microelectrodes

Sadik¹,

Wallace²

1994

Electroanalysis

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The detection of electroinactive ions using conducting polymers has been described previously. In this work. we shon-that the analyrical performance of this method is greatly improved using microelectrodes. The use of microelectrodes overcomes the problems associated with the implementation of this detection scheme in lorn-conductivig-eluents. KEY WORDS: Conducting polymers, Electroinactive ions, Microelectrodes LWRODUCTIONThe use of polymer sensors has attracted considerable attention in recent years [l-31. Of the conducting polymers considered, polypyrrole ( P e ) has attracted the most attention because of the stability and flexibili? available with this system. This latter feature enables the production of electrode surfaces capable of diverse molecular interactions and, hence, a range of sensing operations. The chemical properties of P4; are determined bl-the counterion (A-) incorporated during synthesis according to the following:For example, A-may be a simple anion such as chloride in which case the polymer may be used as a sensor to incorporate appropriate anal>ies via ion exchange [4,5]. However, at the other end of the molecular spectrum, A-may be a complicated biomolecule such as an enzyme [6,7] o r an antibody [8,9] capable of extremely specific molecular recognition.These materials can then be used for sensing with electrical signals based on current flow [ l ] as a result of analge oxidation/reduction, changes in resistance [ 10,11], or capacitance [9] utilized. An additional unique signal generation mechanism exists with conducting polymers such as PPy [12,13]. This involves the generation of a signal owing to oxidation/reduction of the polymer in the presence of the analyte of interest. This mechanism is most appropriately used with flow-injection analysis (FIA) and an eluent whose ions are not readily incorporated during polymer oxidation/reduction. The oxidation/reduction of the polymer is then dependent on the presence of more easily incorporated ions (the analytes) and the degree of osidation/reduction is dependent on the concentration of these species. When used with FIA and pulsed amperometric detection, this gives rise to a unique and sensitive sensing technology. The use of this scheme is appreciated when one realizes that the ion affinity of the conducting polymer for particular anions or cations is readily modified by adjusting the polymer counterion incorporated during synthesis [ 141.This is a usehl mechanism for electrochemical detection of electroinactive ions. However, a quandary exists. The use of carrier eluents with anions that are not readily incorporated inevitably leads to the use of eluenrs containing larger ionic species and/or electrolytes of lower concentration. Such solutions have low conductivity. In a conventional electrochemical cell, this leads to increased iR drop and a loss of control over the applied potential. Consequently, the analytical signal is distorted.The use of microelectrodes, electrodes <20 pm in at least one dimension, in eluents with l...

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“…This has already been advantage of in analyses with flow-through electrochemical detection cells [17,18]. The low current encountered and.…”

Section: Lwroductionmentioning

confidence: 97%

Detection of electroinactive ions using conducting polymer microelectrodes

Sadik¹,

Wallace²

1994

Electroanalysis

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“…To avoid these drawbacks, amperometric gas sensors based on the use of moist ion-exchange membranes as solid polymer electrolytes (SPEs) were developed in the last two decades. [4][5][6][7][8][9][10][11][12][13] In these devices the membrane separating the gaseous samples from the internal electrolyte is not permeated by analytes but serves to provide the transfer of charged species from the working to the counter electrode, thus playing the role assumed by usual supporting electrolytes. Remarkable benefits are gained from the use of this assembly thanks to the elimination of a permeation step.…”

Section: Introductionmentioning

confidence: 99%

An electrochemical gas sensor based on paper supported room temperature ionic liquids

et al. 2012

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A sensitive and fast-responding membrane-free amperometric gas sensor is described, consisting of a small filter paper foil soaked with a room temperature ionic liquid (RTIL), upon which three electrodes are screen printed with carbon ink, using a suitable mask. It takes advantage of the high electrical conductivity and negligible vapour pressure of RTILs as well as their easy immobilization into a porous and inexpensive supporting material such as paper. Moreover, thanks to a careful control of the preparation procedure, a very close contact between the RTIL and electrode material can be achieved so as to allow gaseous analytes to undergo charge transfer just as soon as they reach the threephase sites where the electrode material, paper supported RTIL and gas phase meet. Thus, the adverse effect on recorded currents of slow steps such as analyte diffusion and dissolution in a solvent is avoided. To evaluate the performance of this device, it was used as a wall-jet amperometric detector for flow injection analysis of 1-butanethiol vapours, adopted as the model gaseous analyte, present in headspace samples in equilibrium with aqueous solutions at controlled concentrations. With this purpose, the RTIL soaked paper electrochemical detector (RTIL-PED) was assembled by using 1butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide as the wicking RTIL and printing the working electrode with carbon ink doped with cobalt(II) phthalocyanine, to profit from its ability to electrocatalyze thiol oxidation. The results obtained were quite satisfactory (detection limit: 0.5 mM; dynamic range: 2-200 mM, both referring to solution concentrations; correlation coefficient: 0.998; repeatability: AE7% RSD; long-term stability: 9%), thus suggesting the possible use of this device for manifold applications.

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“…Electroanalytical measurements are precluded in nonconducting media, unless unconventional electrodes suitable for obviating the absence in the sample of supporting electrolytes are adopted. Thus, the use of microelectrodes [1], permeable membrane electrodes [2][3][4] and electrodes supported on perfluorinated ion-exchange polymers [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] has been suggested.…”

Section: Introductionmentioning

confidence: 99%

A Novel Assembly for Perfluorinated Ion-Exchange Membrane-Based Sensors Designed for Electroanalytical Measurements in Nonconducting Media

et al. 1998

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A perfluorinated ion-exchange membrane-based sensor suitable for electroanalytical measurements in electrolyte-free media is described, which is assembled following a novel design enabling an easier preparation procedure. It is fabricated by inserting the terminal portion of a working wire electrode into a Nafion tubing of suitable diameter and welding the wire thus wrapped to the bottom of a cell body by an insulating epoxy resin. The remainder upper part of the working electrode is covered by a Teflon tubing to avoid the electrical contact with the internal electrolyte introduced into the cell body, which is equipped with a counter and a reference electrode. As a result of this configuration, the actual working-electrode surface is the wire circumference contacted by the polyelectrolyte material at the bottom of the assembly which is exposed to the sample. The performance of this sensor has been tested by cyclic voltammetry, amperometric monitoring and flow injection analysis for the electroanalysis of a series of prototype analytes either dissolved in electrolyte-free water (hydrogen peroxide, hydroquinone, ferricyanide, iodide and bromide ions) or present in nitrogen atmospheres (triethylamine and oxygen). Detection limits for these analytes have been estimated for a signal-to-noise ratio of 3, together with the corresponding ranges within which the responses display a linear dependence on the analyte concentration. The results obtained point out that the novel assembly is profitable only for the analysis in electrolyte-free liquid samples, while for the analysis of gaseous atmospheres, especially for flowing gases, ion-exchange membrane sensors prepared by the more usual procedure based on the use of working electrode materials embedded into a moist polyelectrolyte membrane should be preferred.

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A solid polymer electrolyte amperometric detector for FIA and HPLC with mobile phases of low conductivity

Cited by 12 publications

References 10 publications

Detection of electroinactive ions using conducting polymer microelectrodes

Detection of electroinactive ions using conducting polymer microelectrodes

An electrochemical gas sensor based on paper supported room temperature ionic liquids

A Novel Assembly for Perfluorinated Ion-Exchange Membrane-Based Sensors Designed for Electroanalytical Measurements in Nonconducting Media

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