51
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Xu Y, Ngeontae W, Pretsch E, Bakker E. Backside calibration chronopotentiometry: using current to perform ion measurements by zeroing the transmembrane ion flux. Anal Chem 2008; 80:7516-23. [PMID: 18778039 PMCID: PMC2597783 DOI: 10.1021/ac800774e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A recent new direction in ion-selective electrode (ISE) research utilizes a stir effect to indicate the disappearance of an ion concentration gradient across a thin ion-selective membrane. This zeroing experiment allows one to evaluate the equilibrium relationship between front and backside solutions contacting the membrane by varying the backside solution composition. This method is attractive since the absolute potential during the measurement is not required, thus avoiding standard recalibrations from the sample solution and a careful control of the reference electrode potential. We report here on a new concept to alleviate the need to continuously vary the composition of the backside solution. Instead, transmembrane ion fluxes are counterbalanced at an imposed critical current. A theoretical model illustrates the relationship between the magnitude of this critical current and the concentration of analyte and countertransporting ions and is found to correspond well with experimental results. The approach is demonstrated with lead(II)-selective membranes and protons as dominating interference ions, and the concentration of Pb(2+) was successfully measured in tap water samples. The principle was further evaluated with calcium-selective membranes and magnesium as counterdiffusing species, with good results. Advantages and limitations arising from the kinetic nature of the perturbation technique are discussed.
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Affiliation(s)
- Yida Xu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, USA
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52
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Perera H, Shvarev A. Determination of unbiased selectivity coefficients using pulsed chronopotentiometric polymeric membrane ion sensors. Anal Chem 2008; 80:7870-5. [PMID: 18808155 DOI: 10.1021/ac801210u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new procedure for the determination of selectivity coefficients of neutral carriers using pulsed chronopotentiometric ion selective sensors (pulstrodes) is established. Pulstrode membrane which lacks an ion-exchanger suppresses the zero current ion flux, allowing a Nernstian response slope for even highly discriminated ions. Unlike previously developed methods, unbiased selectivity remains unaltered even with the exposure to the primary ion solution for prolonged time. Studies with potassium-, silver-, and calcium-selective electrodes reveal that pulstrodes yield the same or slightly favorable unbiased selectivity coefficients than reported earlier. In contrast to alternative methods for the determination of unbiased selectivity, this technique offers a unique simplicity and reliability. Therefore the new procedure promises to be a valuable additional tool for the characterization of unbiased selectivity coefficients for the ISEs.
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Affiliation(s)
- Hasini Perera
- Department of Chemistry, Oregon State University, 153, Gilbert Hall, Corvallis, Oregon 97331-4003, USA
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53
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Lindner E, Gyurcsányi RE. Quality control criteria for solid-contact, solvent polymeric membrane ion-selective electrodes. J Solid State Electrochem 2008. [DOI: 10.1007/s10008-008-0608-1] [Citation(s) in RCA: 243] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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54
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Bodor S, Zook JM, Lindner E, Tóth K, Gyurcsányi RE. Chronopotentiometric method for the assessment of ionophore diffusion coefficients in solvent polymeric membranes. J Solid State Electrochem 2008. [DOI: 10.1007/s10008-008-0614-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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55
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Element profiles in galvanostatically polarized K+-selective all-solid-state sensors with poly(vinyl chloride)-based membranes. J Solid State Electrochem 2008. [DOI: 10.1007/s10008-008-0578-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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56
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Morf WE, Pretsch E, De Rooij NF. Theory and Computer Simulation of the Time-Dependent Selectivity Behavior of Polymeric Membrane Ion-Selective Electrodes. J Electroanal Chem (Lausanne) 2008; 614:15-23. [PMID: 20411043 DOI: 10.1016/j.jelechem.2007.10.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A theoretical treatment of the time-dependent potential response of ion-selective electrodes to sample solutions containing primary and interfering ions is presented. The theory accounts for the influence of ion fluxes in the electrode membrane and the contacting aqueous sample layer and describes the variations in the apparent selectivity behavior as a function of the measuring time. The applicability of the theory is demonstrated by comparing predicted response curves with results of virtual experiments based on computer simulation. A close and convincing agreement was achieved for a large series of different examples, which confirms that the new theory can be successfully applied for general cases.
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Affiliation(s)
- W E Morf
- Institute of Microtechnology, University of Neuchâtel, Rue Jaquet-Droz 1, CH-2007 Neuchâtel, Switzerland
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57
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Zook JM, Buck RP, Langmaier J, Lindner E. Mathematical model of current-polarized ionophore-based ion-selective membranes. J Phys Chem B 2008; 112:2008-15. [PMID: 18217742 DOI: 10.1021/jp074612i] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A mathematical model is presented to describe the effects of constant current on ion-selective membranes using theta functions. The model provides exact analytic solutions for calculating the concentration polarization of the ionophore, the ion-ionophore complex, and the charged mobile sites in space and time within the membrane. It also predicts the time course of the membrane potential and the electric field inside the membrane following the application of constant current. This analytic solution is faster to compute than numerical simulations and provides the solution for any given time or position directly. The simulated concentration profiles compare favorably with concentration profiles recorded experimentally using spectro-electrochemical microscopy.
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Affiliation(s)
- Justin M Zook
- Department of Biomedical Engineering, The University of Memphis, Memphis, Tennessee 38152, USA
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58
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Affiliation(s)
- Johan Bobacka
- Åbo Akademi University, Process Chemistry Centre, c/o Laboratory of Analytical Chemistry, Biskopsgatan 8, FI-20500 Turku-Åbo, Finland; Faculty of Material Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, PL-30059 Cracow, Poland; and Åbo Akademi University, Process Chemistry Centre, c/o Center for Process Analytical Chemistry and Sensor Technology (ProSens), Biskopsgatan 8, FI-20500 Turku-Åbo, Finland
| | - Ari Ivaska
- Åbo Akademi University, Process Chemistry Centre, c/o Laboratory of Analytical Chemistry, Biskopsgatan 8, FI-20500 Turku-Åbo, Finland; Faculty of Material Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, PL-30059 Cracow, Poland; and Åbo Akademi University, Process Chemistry Centre, c/o Center for Process Analytical Chemistry and Sensor Technology (ProSens), Biskopsgatan 8, FI-20500 Turku-Åbo, Finland
| | - Andrzej Lewenstam
- Åbo Akademi University, Process Chemistry Centre, c/o Laboratory of Analytical Chemistry, Biskopsgatan 8, FI-20500 Turku-Åbo, Finland; Faculty of Material Science and Ceramics, AGH-University of Science and Technology, Al. Mickiewicza 30, PL-30059 Cracow, Poland; and Åbo Akademi University, Process Chemistry Centre, c/o Center for Process Analytical Chemistry and Sensor Technology (ProSens), Biskopsgatan 8, FI-20500 Turku-Åbo, Finland
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59
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Influence of galvanostatic polarisation on evolution of ion concentration profiles in ion-selective membranes, studied by means of laser ablation inductively coupled plasma mass spectrometry. Electrochem commun 2008. [DOI: 10.1016/j.elecom.2007.10.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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60
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Zamani HA, Ganjali MR, Norouzi P, Adib M. Strontium PVC-membrane sensor based on 2-[(2-mercaptophenylimino)methyl]phenol. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2008. [DOI: 10.1016/j.msec.2007.05.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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61
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Performance evaluation criteria for preparation and measurement of macro- and microfabricated ion-selective electrodes (IUPAC Technical Report). PURE APPL CHEM 2008. [DOI: 10.1351/pac200880010085] [Citation(s) in RCA: 179] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Over the last 30 years, IUPAC published several documents with the goal of achieving standardized nomenclature and methodology for potentiometric ion-selective electrodes (ISEs). The ISE vocabulary was formulated, measurement protocols were suggested, and the selectivity coefficients were compiled. However, in light of new discoveries and experimental possibilities in the field of ISEs, some of the IUPAC recommendations have become outdated. The goal of this technical report is to direct attention to ISE practices and the striking need for updated or refined IUPAC recommendations which are consistent with the state of the art of using macro- and microfabricated planar microelectrodes. Some of these ISE practices have never been addressed by IUPAC but have gained importance with the technological and theoretical developments of recent years. In spite of its recognized importance, a generally acceptable revision of the current IUPAC recommendations is far beyond the scope of this work.
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62
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Bodor S, Zook JM, Lindner E, Tóth K, Gyurcsányi RE. Electrochemical methods for the determination of the diffusion coefficient of ionophores and ionophore–ion complexes in plasticized PVC membranes. Analyst 2008; 133:635-42. [DOI: 10.1039/b718110h] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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63
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Perera H, Shvarev A. Unbiased selectivity coefficients obtained for the pulsed chronopotentiometric polymeric membrane ion sensors. J Am Chem Soc 2007; 129:15754-5. [PMID: 18052379 DOI: 10.1021/ja076821m] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report here on the successful observation of the unbiased thermodynamic selectivity of ion-selective sensors working in normal pulse chronopotentiometric mode (pulstrodes). In contrast to ion-selective electrodes, the pulstrodes do not require careful counterbalancing of the transmembrane ionic fluxes to achieve unbiased thermodynamic selectivity. The pulstrodes can work under asymmetric conditions, which are often encountered in practice. The composition of the inner filling solution did not affect the sensor response, indicating that the transmembrane flux of primary ions was indeed effectively suppressed in the absence of ion exchanger. For the K-selective sensor considered here, an improvement of Mg discrimination by a factor of 1000 was demonstrated.
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Affiliation(s)
- Hasini Perera
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA
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64
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65
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Makarychev-Mikhailov S, Shvarev A, Bakker E. Calcium pulstrodes with 10-fold enhanced sensitivity for measurements in the physiological concentration range. Anal Chem 2007; 78:2744-51. [PMID: 16615788 DOI: 10.1021/ac052211y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ion-selective electrodes ideally operate on the basis of the Nernst equation, which predicts less than 60- and 30-mV potential change for a 10-fold activity change of monovalent and divalent ions measured at room temperature, respectively. Typical concentration ranges in extracellular fluids are quite narrow for the electrolytes of key importance. A range of 2.2-2.6 mM for calcium ions, for instance, translates into just a 2.2-mV potential change. The direct potentiometric measurement of physiological electrolytes is certainly possible with direct potentiometry and is done routinely in clinical analyzers and handheld measuring devices. It places, however, strong demands on the precision of the reference electrode and requires careful temperature control and frequent calibration runs. In this paper, a robust 10-20-fold sensitivity enhancement for calcium measurements is attained by departing from the classical response mechanism and operating in a non-Nernstian response mode. Stable and reproducible super-Nernstian responses of these so-called pulstrodes in a narrow calcium activity range can be controlled by instrumental means in good agreement with theory. The potentials may be measured during a galvanostatic excitation pulse (mode I) or immediately after it (mode II), under open-circuit conditions. Subtraction of the potentials, sampled at different times during a single pulse, allows one to obtain a sensitive differential peak-shaped signal at a critical and fully adjustable analyte activity range. Calcium pulstrodes based on the diamide ionophore AU-1 were characterized and applied to the measurement in model physiological liquids. Super-Nernstian responses exceeding 700 mV/decade were observed in a physiological range of calcium concentration. Such remarkable sensitivity of the pulstrodes, complemented with the well-documented high selectivity of these potentiometric sensors, may provide a significant increase in the accuracy and precision of electrolyte measurements in clinical analysis.
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66
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Tompa K, Birbaum K, Malon A, Vigassy T, Bakker E, Pretsch E. Ion-selective supported liquid membranes placed under steady-state diffusion control. Anal Chem 2007; 77:7801-9. [PMID: 16316191 DOI: 10.1021/ac051362y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Supported liquid membranes are used here to establish steady-state concentration profiles across ion-selective membranes rapidly and reproducibly. This opens up new avenues in the area of nonequilibrium potentiometry, where reproducible accumulation and depletion processes at ion-selective membranes may be used to gain valuable analytical information about the sample. Until today, drifting signals originating from a slowly developing concentration profile across the ion-selective membrane made such approaches impractical in zero current potentiometry. Here, calcium- and silver-selective membranes were placed between two identical aqueous electrolyte solutions, and the open circuit potential was monitored upon changing the composition of one solution. Steady state was reached in approximately 1 min with 25-microm porous polypropylene membranes filled with bis(2-ethylhexyl) sebacate doped with ionophore and lipophilic ion exchanger. Ion transport across the membrane resulted on the basis of nonsymmetric ion-exchange processes at both membrane sides. The steady-state potential was calculated as the sum of the two membrane phase boundary potentials, and good correspondence to experiment was observed. Concentration polarizations in the contacting aqueous phases were confirmed with stirring experiments. It was found that interferences (barium in the case of calcium electrodes and potassium with silver electrodes) induce a larger potential change than expected with the Nicolsky equation because they influence the level of polarization of the primary ion (calcium or silver) that remains potential determining.
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Affiliation(s)
- Károly Tompa
- Laboratorium für Organische Chemie, ETH Hönggerberg, Zürich, Switzerland
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67
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Morf WE, Pretsch E, De Rooij NF. Computer Simulation of Ion-Selective Membrane Electrodes and Related Systems by Finite-Element Procedures. J Electroanal Chem (Lausanne) 2007; 602:43-54. [PMID: 20376294 PMCID: PMC2849319 DOI: 10.1016/j.jelechem.2006.11.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A simple but powerful numerical simulation for analyzing the electrochemical behavior of ion-selective membranes and liquid junctions is presented. The computer modeling makes use of a finite-element procedure in the space and time domains, which can be easily processed (e. g., with MS Excel software) without the need for complex mathematical evaluations. It leads to convincing results on the dynamic evolution of concentration profiles, potentials, and fluxes in the studied systems. The treatment accounts for influences of convection, flow, or stirring in the sample solution that act on the boundary diffusion layer and it is even capable of including the effects of an electrolyte flow through the whole system. To minimize the number of arbitrary parameters, interfacial reactions are assumed to be near local equilibrium, and space-charge influences are considered via phase-boundary potential differences. The applicability of the computer simulation is demonstrated for different ion-selective membranes as well as for liquid junctions. The numerical results are in excellent agreement with experimental data.
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Affiliation(s)
- W E Morf
- Institute of Microtechnology, University of Neuchâtel, Rue Jaquet-Droz 1, CH-2007 Neuchâtel, Switzerland
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68
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Vigassy T, Huber CG, Wintringer R, Pretsch E. Monolithic capillary-based ion-selective electrodes. Anal Chem 2007; 77:3966-70. [PMID: 15987098 DOI: 10.1021/ac050424h] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Poly(styrene-co-divinylbenzene)-based monolithic capillaries of an inner diameter of 200 mum and a length of 2-5 mm have been used to construct Ca2+-, Ag+-, and Na+-selective electrodes. The membranes consist of a solution of ionophore and ion exchanger in bis(2-ethylhexyl) sebacate or 2-nitrophenyl octyl ether, which are used as plasticizers in conventional PVC-based membranes. With capillaries of low porosity, the potentiometric responses down to 10(-8)-10(-9) M solutions do not depend on the composition of the internal solution, which indicates a strong suppression of transmembrane ion fluxes. Thus, no tedious optimization of the inner solution is required with monolith ISEs. The lower detection limits of Ag+- and Ca2+-ISEs are comparable to the best ones obtained earlier with optimized inner solutions. Additionally, a monolithic Na+-selective ISE has been obtained exhibiting a lower detection limit of 3 x 10(-8) M Na+. With monolithic capillaries of higher porosity and fused-silica GC capillaries, the transmembrane flux effects are noticeable but still significantly smaller than with conventional PVC membranes.
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Affiliation(s)
- Tamás Vigassy
- Laboratorium für Organische Chemie, ETH Hönggerberg, CH-8093 Zürich, Switzerland
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69
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Gyurcsányi RE, Lindner E. Spectroelectrochemical microscopy: spatially resolved spectroelectrochemistry of carrier-based ion-selective membranes. Anal Chem 2007; 77:2132-9. [PMID: 15801747 DOI: 10.1021/ac048445j] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-resolution spectroscopic imaging of the cross section of ion-selective membranes and the adjoining solution phases during real-time electrochemical measurement is termed as spectroelectrochemical microscopy (SpECM). The novel SpECM instrument utilizes wavelength-dispersive multispectral imaging of a thin membrane strip separating the two sides of a four-electrode thin-layer electrochemical cell. SpECM is aimed as a tool for optimizing the experimental conditions in mass transport-controlled ion-selective electrode membranes for improved detection limit. Some of the capabilities of the new technique are demonstrated using fix site, chromoionophore-based, pH-sensitive membranes as model systems. The experimental results are discussed in the light of the existing theory of fixed-site membranes. The quantitative expression for the time-dependent change of the free ionophore concentration across the ion-selective membrane showed close correlation to the recorded concentration profiles.
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Affiliation(s)
- Róbert E Gyurcsányi
- Institute of General and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, Budapest, Hungary-1111
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70
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Zamani HA, Ganjali MR, Seifi N. Dysprosium(III) Ion-Selective Electrochemical Sensor Based on 6-Hydrazino-1,5-diphenyl-6,7-dihydropyrazolo[3,4-d]pyrimidine-4(5H)-imine. ACTA ACUST UNITED AC 2007. [DOI: 10.1135/cccc20071189] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A Dy(III) ion-selective electrode based on 6-hydrazino-1,5-diphenyl-6,7-dihydropyrazolo[3,4-d]pyrimidine-4(5H)-imine (HDDPI) as an excellent sensing material was developed. The sensor exhibits a Nernstian behavior (a slope of 19.6 ± 0.3 mV per decade) over a wide concentration range (from 1.0 × 10-1 to 8.0 × 10-7 M Dy) with a detection limit of 4.2 × 10-7 M. The sensor response is independent of pH of the solution in the pH range 3.5-8.3. The sensor possesses the advantages of short conditioning time, fast response time (<10 s) and in particular, good selectivity and sensitivity to the dysprosium ion in the presence of a variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor also showed a great enhancement in selectivity coefficients for dysprosium ions, in comparison with the formerly mentioned dysprosium sensors. The electrode can be used for at least 10 weeks without any considerable divergence in the potentials. The proposed electrode was successfully used as an indicator electrode in potentiometric titration of Dy(III) ions with EDTA. The membrane sensor was also used in the determination of concentration of F- ions in some mouth washing solutions and in the Dy3+ recovery from solution.
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71
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Abstract
For most chemists, potentiometry with ion-selective electrodes (ISEs) primarily means pH measurements with a glass electrode. Those interested in clinical analysis might know that ISEs, routinely used for the determination of blood electrolytes, have a market size comparable to that of glass electrodes. It is even less well known that potentiometry went through a silent revolution during the past decade. The lower detection limit and the discrimination of interfering ions (the selectivity coefficients) have been improved in many cases by factors up to 10(6) and 10(10), respectively, thus allowing their application in fields such as environmental trace analysis and potentiometric biosensing. The determination of complex formation constants for lipophilic hosts and ionic guests is also covered in this Minireview.
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Affiliation(s)
- Eric Bakker
- Prof. Eric Bakker, Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA, E-mail:
| | - Ernö Pretsch
- Prof. Ernö Pretsch, Laboratorium für Organische Chemie, ETH Zürich, CH-8093 Zürich, Switzerland, E-mail:
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72
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Zhao C, Danish E, Cameron NR, Kataky R. Emulsion-templated porous materials (PolyHIPEs) for selective ion and molecular recognition and transport: applications in electrochemical sensing. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b700929a] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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73
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Radu A, Diamond D. Chapter 2 Ion-selective electrodes in trace level analysis of heavy metals: Potentiometry for the XXI century. ELECTROCHEMICAL SENSOR ANALYSIS 2007. [DOI: 10.1016/s0166-526x(06)49002-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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74
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Radu A, Peper S, Bakker E, Diamond D. Guidelines for Improving the Lower Detection Limit of Ion-Selective Electrodes: A Systematic Approach. ELECTROANAL 2007. [DOI: 10.1002/elan.200603741] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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75
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Konopka A, Sokalski T, Lewenstam A, Maj-Żurawska M. The Influence of the Conditioning Procedure on Potentiometric Characteristics of Solid Contact Calcium-Selective Electrodes in Nanomolar Concentration Solutions. ELECTROANAL 2006. [DOI: 10.1002/elan.200603652] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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76
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Bereczki R, Takács B, Gyurcsányi R, Tóth K, Nagy G, Langmaier J, Lindner E. Simple, Single Step Potential Difference Measurement for the Determination of the Ultimate Detection Limit of Ion Selective Electrodes. ELECTROANAL 2006. [DOI: 10.1002/elan.200603521] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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77
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Pawłowski P, Michalska A, Maksymiuk K. Galvanostatic Polarization of All-Solid-State K+-Selective Electrodes with Polypyrrole Ion-to-Electron Transducer. ELECTROANAL 2006. [DOI: 10.1002/elan.200603553] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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78
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Móczár I, Gyurcsányi R, Huszthy P, Jágerszki G, Tóth K, Lindner E. Synthesis and Characterization of a Novel, Colored Lipophilic Additive for Spectral Imaging the Transport in Ionophore Based Ion-Selective Membranes. ELECTROANAL 2006. [DOI: 10.1002/elan.200603551] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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79
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Szigeti Z, Vigassy T, Bakker E, Pretsch E. Approaches to Improving the Lower Detection Limit of Polymeric Membrane Ion-Selective Electrodes. ELECTROANAL 2006; 18:1254-1265. [PMID: 20336172 PMCID: PMC2844646 DOI: 10.1002/elan.200603539] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2006] [Accepted: 04/03/2006] [Indexed: 11/10/2022]
Abstract
More than ten different approaches for improving the lower detection limit of polymeric membrane ion-selective electrodes have been suggested during the recent years. In this contribution, their principles are briefly summarized with a focus to their general practical applicability. The methods that are the most rugged and the easiest to implement in a routine laboratory will be highlighted.
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Affiliation(s)
- Zsófia Szigeti
- Laboratorium für Organische Chemie, ETH-Hönggerberg, HCI E313, CH-8093 Zürich, Switzerland
| | - Tamás Vigassy
- Laboratorium für Organische Chemie, ETH-Hönggerberg, HCI E313, CH-8093 Zürich, Switzerland
| | - Eric Bakker
- Department of Chemistry, 560 Oval Drive, Purdue University, West Lafayette, IN 47907, USA
| | - Ernö Pretsch
- Laboratorium für Organische Chemie, ETH-Hönggerberg, HCI E313, CH-8093 Zürich, Switzerland
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80
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Konopka A, Sokalski T, Michalska A, Lewenstam A, Maj-Zurawska M. Factors affecting the potentiometric response of all-solid-state solvent polymeric membrane calcium-selective electrode for low-level measurements. Anal Chem 2006; 76:6410-8. [PMID: 15516135 DOI: 10.1021/ac0492158] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An all-solid-state calcium-selective electrode was constructed with poly(pyrrole) solid-contact doped with calcium complexing ligand Tiron. The potentiometric response of this sensor can have a linear range down to 10(-)(9) M with a slope close to Nernstian and detection limit equal to 10(-)(9.6). The effects of pH and the activity of the interfering ion in the conditioning solution on the potentiometric behavior of the constructed sensors were examined. Potential stability, reproducibility, and impedance studies were performed. The selectivity of the constructed electrode is better than that of the conventional calcium-selective electrode with internal filling solution of 10(-)(2) M CaCl(2) and comparable to that of the best liquid-contact electrodes.
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Affiliation(s)
- Anna Konopka
- Faculty of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
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81
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Sutter J, Pretsch E. Response Behavior of Poly(vinyl chloride)- and Polyurethane-Based Ca2+-Selective Membrane Electrodes with Polypyrrole- and Poly(3-octylthiophene)-Mediated Internal Solid Contact. ELECTROANAL 2006. [DOI: 10.1002/elan.200503373] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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82
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Gyurcsányi RE, Lindner E. Multispectral imaging of ion transport in neutral carrier-based cation-selective membranes. Cytometry A 2006; 69:792-804. [PMID: 16969802 DOI: 10.1002/cyto.a.20276] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND High-resolution spectroscopic imaging of the cross section of ion-selective membranes during real-time electrochemical measurements is termed spectroelectrochemical microscopy (SpECM). SpECM is aimed for optimizing the experimental conditions in mass transport controlled ion-selective electrode (ISE) membranes for improved detection limit. METHODS The SpECM measurements are performed in a thin layer electrochemical cell. The key element of the cell is a membrane strip spacer ring assembly which forms a two compartment electrochemical cell. The cell is placed onto the stage of a microscope and the membrane strip is positioned in the center of the field of view. A slice of the image is focused onto the entrance slit of the imaging spectrometer. RESULTS SpECM has been used for the determination of the diffusion coefficients of different membrane ingredients and for the quantitative assessment of the charged site concentrations in ISE membranes and membrane plasticizers. In addition, changes in the concentration profiles of the ionophore (free and complexed) and charged mobile sites inside the ISE membranes are documented upon the application of large external voltages. CONCLUSIONS This account demonstrates the power and advantages of SpECM, a multispectral imaging method for investigations of mass transport processes in ISE membranes during electrochemical measurements.
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Affiliation(s)
- Robert E Gyurcsányi
- Department of General and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, 1111 Budapest, Hungary
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83
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Bereczki R, Takács B, Langmaier J, Neely M, Gyurcsányi RE, Tóth K, Nagy G, Lindner E. How To Assess the Limits of Ion-Selective Electrodes: Method for the Determination of the Ultimate Span, Response Range, and Selectivity Coefficients of Neutral Carrier-Based Cation Selective Electrodes. Anal Chem 2005; 78:942-50. [PMID: 16448072 DOI: 10.1021/ac050614s] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The span and range of an ion-selective electrode (ISE) has been identified by IUPAC as a potential or activity difference between the upper and lower detection limits of the electrode. Once the span is known, the ultimately attainable detection limit of the ISE can be calculated using its theoretical response slope. In this paper, we propose an original method for the determination of the ultimate span and response range of ISEs. The simple measurement of span is recommended to aid the fast screening of novel ionophores and help to focus optimization processes to the most promising candidates. The measurement of span is combined with a generally applicable procedure for the determination of the three seminal parameters of ISEs: the response slope, the ultimate selectivity coefficients, and detection limit. In the proposed procedure, following the span measurement, two subsequent exponential dilution experiments are completed in which the responses of the electrode for the primary and the interfering ions are tested using a solution of a discriminated ion and deionized water as diluting electrolytes in consecution. The advantages and the practical usefulness of the proposed methods and procedures are demonstrated through the evaluation of the performance characteristics of novel and well-characterized ionophore-based potassium and calcium sensors.
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Affiliation(s)
- Róbert Bereczki
- Research Group for Technical Analytical Chemistry of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, Hungary
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84
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Michalska A. Optimizing the analytical performance and construction of ion-selective electrodes with conducting polymer-based ion-to-electron transducers. Anal Bioanal Chem 2005; 384:391-406. [PMID: 16365779 DOI: 10.1007/s00216-005-0132-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 09/07/2005] [Accepted: 09/21/2005] [Indexed: 11/28/2022]
Abstract
All-solid-state ion-selective electrodes that use a conducting polymer as the ion-to-electron transducer have emerged as one of the most promising classes of all-solid-state potentiometric sensors in recent years. This is largely because it has many analytical advantages, including high response stability, which is unique in the field of internal-solution-free ion-selective electrodes. This paper reviews the considerable progress that has been made in this area of sensing in recent years, in terms of detection limits, selectivity coefficients and novel construction methods.
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Affiliation(s)
- Agata Michalska
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093, Warsaw, Poland.
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85
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Influence of cationic and anionic additives on the electrical properties of ionophore-based ion-selective membranes. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2005.04.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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86
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Michalska A, Maksymiuk K. The influence of spontaneous charging/discharging of conducting polymer ion-to-electron transducer on potentiometric responses of all-solid-state calcium-selective electrodes. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2004.10.030] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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87
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Michalska A. Improvement of Analytical Characteristic of Calcium Selective Electrode with Conducting Polymer Contact. The Role of Conducting Polymer Spontaneous Charge Transfer Processes and Their Galvanostatic Compensation. ELECTROANAL 2005. [DOI: 10.1002/elan.200403173] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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88
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Abstract
This review summarizes recent progress in the development and application of potentiometric sensors with limits of detection (LODs) in the range 10(-8)-10(-11) M. These LODs relate to total sample concentrations and are defined according to a definition unique to potentiometric sensors. LODs calculated according to traditional protocols (three times the standard deviation of the noise) yield values that are two orders of magnitude lower. We are targeting this article at analytical chemists who are non-specialists in the development of such sensors so that this technology may be adopted by a growing number of research groups to solve real-world analytical problems.We discuss the unique response features of potentiometric sensors and compare them to other analytical techniques, emphasizing that the choice of the method must depend on the problem of interest. We discuss recent directions in sensor design and development and present a list of 23 sensors with low LODs, with references. We give recent examples where potentiometric sensors have been used to solve trace-level analytical problems, including the speciation of lead and copper ions in drinking water, the measurement of free copper in sea water, and the uptake of cadmium ions by plant roots as a function of their speciation.
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Affiliation(s)
- Eric Bakker
- Department of Chemistry, Auburn University, AL 36849, USA
| | - Ernö Pretsch
- Laboratorium für Organische Chemie, ETH Hönggerberg, CH-8093 Zürich, Switzerland
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89
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Fouskaki M, Chaniotakis NA. Thick Membrane, Solid Contact Ion Selective Electrode for the Detection of Lead at Picomolar Levels. Anal Chem 2005; 77:1780-4. [PMID: 15762585 DOI: 10.1021/ac049013b] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A new approach for decreasing the lower detection limit of a lead ion selective electrode (ISE) is presented. The ISE is designed using nonfunctionalized porous glassy carbon loaded with ionophore/plasticizer/additive cocktail. This material acts both as the support for the liquid polymeric membrane and as the signal transducer of the ISE. The high purity of the glassy carbon, together with its high conductivity, allows for the development of a thick, low-resistance composite membrane. This sensor element enables the continuous measurement of lead down to picomolar levels, with very small detection limit deterioration due to the lead ion transport within the bulk of the thick membrane.
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Affiliation(s)
- Maria Fouskaki
- Laboratory of Analytical Chemistry, University of Crete, Iraklion 71 409 Crete, Greece
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90
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Bereczki R, Gyurcsányi RE, Agai B, Tóth K. Synthesis and characterization of covalently immobilized bis-crown ether based potassium ionophore. Analyst 2005; 130:63-70. [PMID: 15614355 DOI: 10.1039/b410410b] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of a novel covalently immobilized crown ether based potassium ionophore is presented. Apart from previously proposed methods for the preparation of PVC linked ionophores based on the chemical modification of functionalized PVC polymers, the hereby proposed procedure involves the direct copolymerization of a suitable derivative of the bis-crown ether type potassium ionophore (BME 44) and vinyl chloride monomer. The analytical performance of the potentiometric ion selective electrodes incorporating the PVC bound ionophore were optimized and determined. Compared with electrodes based on other bis-crown ether type immobilized potassium selective ionophores a slightly improved logK(K, Na)(Pot) and a longer lifetime was found. Spectral imaging and chronoamperometry were used to study the mobility of different bis-crown ether derivatives in plasticized PVC membranes.
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Affiliation(s)
- Róbert Bereczki
- Research Group for Technical Analytical Chemistry of the Hungarian Academy of Sciences, Budapest University of Technology and Economics, Szt. Gellert ter 4, Budapest 1111, Hungary
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91
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Michalska A, Maksymiuk K. All-plastic, disposable, low detection limit ion-selective electrodes. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.07.020] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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92
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Sutter J, Radu A, Peper S, Bakker E, Pretsch E. Solid-contact polymeric membrane electrodes with detection limits in the subnanomolar range. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.07.016] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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93
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Sutter J, Morf WE, de Rooij NF, Pretsch E. Current response of ion-selective solvent polymeric membranes at controlled potential. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2004.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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94
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Gyurcsányi RE, Jágerszki G, Kiss G, Tóth K. Chemical imaging of biological systems with the scanning electrochemical microscope. Bioelectrochemistry 2004; 63:207-15. [PMID: 15110274 DOI: 10.1016/j.bioelechem.2003.12.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2003] [Revised: 12/09/2003] [Accepted: 12/11/2003] [Indexed: 11/21/2022]
Abstract
A brief overview on recent advances in the application of scanning electrochemical microscopy (SECM) to the investigation of biological systems is presented. Special emphasis is given to the mapping of local enzyme activity by SECM, which is exemplified by relevant original systems.
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Affiliation(s)
- Róbert E Gyurcsányi
- Institute of General and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, Budapest, 1111-Hungary.
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95
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Püntener M, Vigassy T, Baier E, Ceresa A, Pretsch E. Improving the lower detection limit of potentiometric sensors by covalently binding the ionophore to a polymer backbone. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2003.10.030] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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96
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Bratov A, Abramova N, Domı́nguez C. Lowering the detection limit of calcium selective ISFETs with polymeric membranes. Talanta 2004; 62:91-6. [DOI: 10.1016/s0039-9140(03)00402-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2003] [Revised: 05/29/2003] [Accepted: 06/25/2003] [Indexed: 10/27/2022]
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97
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Michalska A, Dumańska J, Maksymiuk K. Lowering the Detection Limit of Ion-Selective Plastic Membrane Electrodes with Conducting Polymer Solid Contact and Conducting Polymer Potentiometric Sensors. Anal Chem 2003. [DOI: 10.1021/ac034335l] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Agata Michalska
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
| | - Joanna Dumańska
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
| | - Krzysztof Maksymiuk
- Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
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98
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99
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Vigassy T, Gyurcsányi R, Pretsch E. Influence of Incorporated Lipophilic Particles on Ion Fluxes Through Polymeric Ion-Selective Membranes. ELECTROANAL 2003. [DOI: 10.1002/elan.200390043] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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100
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