University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
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Selectivity coefficient

Classification: Chemical constant -> Selectivity coefficient

Citations 6

"Selectivity In Flow Injection Analysis"
Anal. Chim. Acta 1983 Volume 148, Issue 1 Pages 111-125
E. H. Hansen and J. RikaF. J. Krug and E. A. G. Zagatto

Abstract: A generalized method for assessing the extent of interference of foreign species on a given chemical assay is proposed. The interference can be quantified by a parameter termed selectivity coefficient. The method is based on injecting the analyte and the interfering species simultaneuosly, and then letting them merge eithe synchronously or asynchromously; the analytical readout is taken from the element of fluid where the dispersion of the two species is identical. It is shown that this makes the accompanying calculations simple, because the selectivity coefficient can be related directly to the originally injected concentrations. The general method is demonstrated for a spectrophotometric procedure for the determination of manganese with formaldoxime, and the selectivity coefficients for various metal ion are determined. The applicability of three different f.i.a. manifold configurations is discussed.
Manganese

"Enhancement Of Sensor Selectivity By Gas Diffusion Separation. Part 1. Flow Injection Potentiometric Determination Of Cyanide With A Metallic Silver-wire Electrode"
Anal. Chim. Acta 1990 Volume 233, Issue 1 Pages 77-84
W. Frenzel, C. Y. Liu and J. Oleksy-Frenzel

Abstract: The potentiometric response of a metallic silver-wire electrode in the presence of Ag+-complexing agents was theoretically derived on the basis of the Nernst equation and compared with experimental results. The construction of the silver-wire sensor is described and details are given of its application in gas diffusion flow injection analysis. Microporous polypropylene membranes were used to separate the donor and acceptor channels allowing almost specific determination of CN-. Gaseous interferents, e.g., H2S, SO2 and nitrogen oxides, were chemically converted before entering the gas diffusion unit. The lifetime of the sensor was more than several months. The calibration graph was rectilinear from 10 µM to 10 mM CN-, and concentration. of 0.1 M were measured for long periods without alteration of the response. The continuous corrosion process did not dissolve significant amounts of silver, which was a significant advantage over the common AgI membrane electrodes. The apparent selectivity coefficient obtained were significantly better than those reported for common CN--selective membranes.
Cyanide Potentiometry Electrode Sensor

"Robust Estimation Of Selectivity Coefficients Using Multivariate Calibration Of Ion-selective Electrode Arrays"
Anal. Chim. Acta 1993 Volume 276, Issue 1 Pages 75-86
Dermot Diamond* and Robert J. Forster

Abstract: Selectivity coefficients for Na, Ca, and K ISE estimated by traditional methods, e.g., separate and mixed solution methods, are compared with values obtained by an approach using multivariate calibration using simplex optimization and non-linear modeling of the array characteristics. The method was used to predict the concentration. of Sa, Ca and K in blood plasma and mineral water samples using dip and FIA measurements. For the array FIA data, the possibility of using an enhanced kinetic-based selectivity for analytical measurements is raised. Further improvement in the three-electrode array performance by using a fourth multiple ionophore electrode is discussed. Results obtained are compared with single electrode dip and FIA measurements of Na in plasma samples.
Sodium Calcium Potassium Blood Plasma Mineral Electrode

"Flow Injection Analysis Potentiometric Selectivity Study Of Alkali Metal And Alkaline Earth Cation Complexation By 1,3-bis(tropone-2'-oxy)propane"
Microchem. J. 1988 Volume 38, Issue 2 Pages 246-250
Abdulrahman S. Attiyat, Gary D. Christian, Michael J. Pugia and Richard A. Bartsch

Abstract: The cited ligand (prep. described) was incorporated into PVC membrane electrodes comprising 2-nitrophenyl octyl ether, K tetrakis-(4-chlorophenyl)borate and PVC on Ag wire, and the electrodes were placed in a flow system for determination of alkali and alkaline-earth metals. The flow-system carrier stream was 14 mM NaCl (1 mL min-1), 200 µL portions of sample solution were injected and the reference electrode was Ag - AgCl. Selectivity coefficient for eight metal ions are tabulated. The electrode response for Li+ increased significantly when TOPO was incorporated into the membrane matrix.
Lithium Metals, alkali Metals, alkaline earth Electrode Potentiometry

"Estimation Of Partition-coefficients Using FIA And Flow-through Membrane Electrodes"
Chem. Anal. 1991 Volume 36, Issue 5-6 Pages 855-861
Blaskiewicz, T.;Staroscik, R.;Zaleska, E.

Abstract: The selectivity coefficients of electrodes based on tricaprylmethylammonium ion pairs in decanol were correlated with the octanol-water partition coefficients for several barbiturates under optimized flow conditions. A fair correlation between the selectivity coefficients, detection limit, and octanol-water partition coefficients was found. (SFS)
Electrode Electrode

"Influence Of Some Parameters On Membrane Selectivity In Flow Injection Potentiometry"
Izv. Khim. 1990 Volume 23, Issue 2 Pages 167-171
Ilcheva, L.;Yanakiev, R.

Abstract: Selectivity coefficient >1 of commercial Cl--, Br-- and NO3--selective electrodes towards various interfering species in conventional potentiometry can be considerably improved if the electrodes are used as sensors in flow injection analysis. The selectivity can be further improved by increasing the carrier-stream flow rate, decreasing the injection volume, and use of the method of standard additions. The interference from 0.6 mM Br- was thereby overcome when determining ~0.1 to 0.2 M Cl- in seawater by the flow injection technique with a Cl--selective electrode.
Chloride Sea Electrode Potentiometry