Ion-selective electrodes, for

The change in the concentration of H3O+ is monitored with a pH ion-selective electrode, for which the cell potential is given by equation 11.9. The relationship between the concentration of H3O+ and CO2 is given by rearranging the equilibrium constant expression for reaction 11.10 thus... 

The preparation of an ion-selective electrode for salicylate is described. The electrode incorporates an ion-pair of crystal violet and salicylate in a PVC matrix as the ion-selective membrane. Its use for the determination of acetylsalicylic acid in aspirin tablets is described. A similar experiment is described by Creager, S. E. Lawrence, K. D. Tibbets, C. R. in An Easily Constructed Salicylate-Ion-Selective Electrode for Use in the Instructional Laboratory, /. Chem. Educ. 1995, 72, 274-276. 

Ericke, G. H. Kuntz, M. J. Inexpensive Solid-State Ion-Selective Electrodes for Student Use, /. Chem. Educ. 1977,... 

Individual polyethers exhibit varying specificities for cations. Some polyethers have found appHcation as components in ion-selective electrodes for use in clinical medicine or in laboratory studies involving transport studies or measurement of transmembrane electrical potential (4). The methyl ester of monensin [28636-21 -7] i2ls been incorporated into a membrane sHde assembly used for the assay of semm sodium (see Biosensors) (5). Studies directed toward the design of a lithium selective electrode resulted in the synthesis of a derivative of monensin lactone that is highly specific for lithium (6). 

USING OF ION SELECTIVE ELECTRODES FOR THE DETERMINATION OF THE IONIC LIQUIDS SOLUBILITY... 

Kimura and coworkers [17], Diamond [18], and Damien et al. [19] have described that the polymeric calix-[4]arenes have been used as ionophores in ion selective electrodes for Na (based on calixarene esters and amides) and for Na and Cs (based on p-alkylcalixarene acetates). The electrodes are stated to function as poten-tiometric sensors as well, having good selectivity for primary ion, virtually no response to divalent cations, and being stable over a wide pH range. 

Where-high purity MU is provided for higher pressure WT boiler plant FW, some form of continuous analyzers for measuring treated water pH and conductivity are almost always installed, as are sodium (Na) ion-selective electrodes for detection of sodium leakage. Automatic online silica analyzers also may be installed, but they measure only reactive (ionizable) silica (Si02), not colloidal or total silica, so caution is required where unforeseen silica leakage may present a problem. 

De Marco R, Mackey DJ (2000) Calibration of a chalcogenide glass membrane ion-selective electrode for the determination of free Fe in seawater I. Measurements in UV photooxidised seawater. Mar Chem 68 283-294 Van den Berg CMG (2000) Mar Chem 71 331-332... 

Pectins in the acidic form were dissolved either in pure water or in 0.1 M NaNOs and put to pH -7.2 by adding 0.05 M NaOH. Various amounts of metal ions were added to pectins solutions at two different concentrations, for 2 h under stirring at 25.0 0.1°C. Concentration of metal ions in solution at equilibrium was determined either by a potentiometric method using ion-selective electrodes for Cu2+ and Pb2+ or by a spectrophotometric method using tetramethylmurexide dye (Kwak Joshi, 1981) for Ni2+, Tsfi and Ca2+. 

One barrel-tip contains the organic membrane phase and an internal reference electrode the other constitutes a second reference electrode. A four-barrel configuration with a 1-pm tip in which three barrels are liquid membrane electrodes for Na, Ca and and the fourth is a reference electrode has been reported Some representative applications of ion-selective electrodes for intracellular measurements are shown in Table 3. 

E. Bakker and M.E. Meyerhoff, Ion-selective electrodes for measurements in biological fluids, in AJ. Bard, M. Stratmann,. and J.S. Wilson, eds, Encyclopedia of Electrochemistry, Wiley (2002). 

R.W. Burnett, A.K. Covington, N. Fogh-Andersen, W.R. Kulpmann, A. Lewenstam, A.H.J. Maas, O. Muller-Plathe, A.L. Vankessel, and W.G. Zijlstra, Use of ion-selective electrodes for blood-electrolyte analysis. Recommendations for nomenclature, definitions and conventions. Clin. Chem. Lab. Med. 38, 363-370 (2000). 

P. Anker, E. Wieland, D. Ammann, R.E. Dohner, R. Asper, and W. Simon, Neutral carrier based ion-selective electrode for the determination of total calcium in blood-serum. Anal. Chem. 53, 1970-1974... 

The properties of a pH electrode are characterized by parameters like linear response slope, response time, sensitivity, selectivity, reproducibility/accuracy, stability and biocompatibility. Most of these properties are related to each other, and an optimization process of sensor properties often leads to a compromised result. For the development of pH sensors for in-vivo measurements or implantable applications, both reproducibility and biocompatibility are crucial. Recommendations about using ion-selective electrodes for blood electrolyte analysis have been made by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) [37], IUPAC working party on pH has published IUPAC s recommendations on the definition, standards, and procedures... 

Calibration of ion-selective electrodes for use in quantitative analysis is usually done by preparing a series of standards as in most other instrumental analysis methods (see Chapter 7), since the measured potential is proportional to the logarithm of the concentration. The relationship is... 

Figure 3.10 Schematic diagram of a solid-state ion-selective electrode for measuring the concentrations of aqueous fluoride ions - the so called fluoride electrode . The silver wire acts as one of the electrodes, so an additional electrode is required to complete the cell.

A different direction in ion-selective electrode research is based on experiments with antibiotics that uncouple oxidative phosphorylation in mitochondria [59]. These substances act as ion carriers (ionophores) and produce ion-specific potentials at bilayer lipid membranes [72]. This function led Stefanac and Simon to obtain a new type of ion-selective electrode for alkali metal ions [92] and is also important in supporting the chemi-osmotic theory of oxidative phosphorylation [69]. The range of ionophores, in view of their selectivity for other ions, was broadened by new synthetic substances [1,61]. 

The usefulness of the ion-selective electrode for determining ion J is Umited by the distribution equilibrium for salt JA between the membrane and solution 1. If the activity of ion J which is present in solution 1 only as a result of this distribution equihbrium, is much smaller than the overall activity aj+(l), then the dependence of the membrane potential on the activity of determinand J has Nernstian slope. If this condition is not fulfilled, then the ISE behaviour can be obtained from the equation for the distribution equihbrium... 

A. Liberti, Ion selective electrodes for heterogeneous polythene membranes, in... 

In the last ten years or so a large number of varied ion-exchanger ions have appeared, suitable for ion-selective electrodes for various cations and anions. 

Ion-selective electrodes for nitrates, other oxygen-containing... 

Ion-selective electrodes for potassium and other monovalent cations... 

Shoukry et al. have prepared plastic membrane ion-selective electrodes for the determination of procaine and other anaesthetic compounds [69]. The electrode selective for procaine was prepared with the use of a membrane containing 15% of the procaine tetraphenylborate ion pair with 40% of dioctyl phthalate and 45% of poly vinyl chloride (PVC). The membrane was attached as a disc (12 mm diameter, 0.3 mm thick) to the polished PVC cap of the electrode tube, which contained an internal solution of 0.1 M sodium chloride made 1 mM in the same drug, and in contact with a Ag-AgCl wire. Linear response ranges were determined to be 20.0 pM to 16 mM for procaine over the pH range of 3.1 to 7.9. The electrodes could also be used in the potentiometric titration of the drug with 0.01 M sodium tetraphenylborate. 

Hamada et al. used a poly (vinyl chloride) matrix membrane ion-selective electrode for the analysis of procaine [76]. Procaine flavianate (10 mg, prepared by precipitation from an equimolar mixture of procaine hydrochloride and flavianic acid), was mixed with PVC powder (150 mg), dioctyl phthalate (370 mg), and tetrahydrofuran (4 mL). This mixture was used to produce membranes (3 cm diameter), from which discs were cut to prepare ion-selective electrodes. The electrodes were used in conjunction with a double-junction Ag-AgCl (KNO3) reference electrode for the potentiometric determination of procaine hydrochloride at 25°C. 

Ion-selective electrodes for fluoride trace analysis are commercially available and effective down to a level of mg dm [56]. A recent textbook by Cattrall [57] gives background information to the theory... 

A number of Cd(II) sensors based mainly on the Ag2S/CdS mixtures [384, 385] and cadmium chelates [386] were described. Ito etal. [387] used an Ag2S/CdS ion-selective electrode for determination of cadmium ion in industrial wastewater by titration method. 

Analytical issues (i) X-ray elemental microanalysis (ii) Ion-selective electrodes for chnical use. (iii) Electron probe and electron energy loss analysis. (iv) Intracellular measurements . (v) Determination of Mg in human tissues and fluids . (vi) Trace elements in hair. (vii) Determination of Ca and Mg in wines . 

N. A. Chaniotakis, Thick Membrane, Solid Contact Ion Selective Electrode for the Detection of Lead at Picomolar Levels, Anal. Chem. 2005, 77, 1780. 

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