Ion-selective microelectrodes

Sykova, E., Hnik, P., Vyklicky, L. (eds.) Ion-Selective Microelectrodes and Their Use in Excitable Tissues, New York Plenum Press 1981... 

Zeuthen, T. (ed.) The Application of Ion-Selective Microelectrodes, New York Elsevier/North-Holland Biomedical Press 1981... 

In electrophysiology ion-selective microelectrodes are employed. These electrodes, resembling micropipettes (see Fig. 3.8), consist of glass capillaries drawn out to a point with a diameter of several micrometres, hydrophobized and filled with an ion-exchanger solution, forming the membrane in the ion-selective microelectrode. 

Ammann, D., Ion-Selective Microelectrodes, Springer-Verlag, Berlin, 1986. 

Nairn, A., and Pretsch, E. (1994). Potentiometric detection of anions separated by capillary electrophoresis using an ion-selective microelectrode. /. Chromatogr. A 676, 437-442. 

Ion-Selective Microelectrodes (ed. H. J. Beiman and N. C. Hebeit), Plenum Piess,... 

Ion-Selective Microelectrodes and Their Use in Excitable Tissues (ed. E. Sykovd,... 

Ion-selective microelectrodes [18, 70,71, 164] are chiefly used for measurement of ion activities in individual cells and in intracellular liquid. They were developed from micropipettes, which are miniature liquid bridges used for measurement of cell membrane potentials [94]. Micropipettes and ion-selective microelectrodes are made using commercial drawing devices. Ion-selective... 

The first factor, especially important with ion-selective microelectrodes, can be eliminated by a suitable modification of the measuring instrument, notably by the use of a coaxial microelectrode (see [167] and section 4.2). If an inter-ferent is present in the solution at a concentration at which it does not affect the ISE potential, factors 4 and 6 are not operative. Penetration of the deter-minand into the membrane, factor 5, is very important for the response times of ISEs with ionophores in their membranes, provided that no hydrophobic anion is present in the membrane solution, as has been theoretically treated by Morf et aL [114]. As shown in section 3.3, the presence of a hydrophobic anion stabilizes the conditions in the membrane, with a marked effect on the shortening of the response time [93]. 

J. Koryta, Theory of ion-selective electrodes, in Ion-Selective Microelectrodes... 

The greater conductivity of an ion-exchanger solution containing the potassium salt of anion XVI in solvent 3-o-nitroxylene (Corning No. 476200) [13a] is a reason for the popularity of this system for electrophysiological measurements using ion-selective microelectrodes [216]. Application of this sensor is so widespread that only reviews and books will be mentioned, for microelectrodes in intracellular measurements [23, 32, 78, 86, 211, 217] and for the determination of K in the intercellular liquid [78]. A working valinomycin microelectrode has also been constructed [166]. 

The solid-membrane ISE has certain disadvantages for the determination of chloride inside cells and thus ion-selective microelectrodes containing ion-exchanger Corning No. 477315 (based on a nitroxylene mixture) are used [223]. Reviews of intracellular applications of this electrode can be found in [23, 78, 86, 211,217]. 

Hrabetova S, Nicholson C. Biophysical properties of brain extracellular space explored with ion-selective microelectrodes, integrative optical imaging and related techniques. In Michael AC, Borland LM (Eds), Electrochemical Methods for Neuroscience. CRC Press/ Taylor Francis, Boca Raton, FL, 2007 167-204. 

In biological systems, most of the elements are present as complexes, rather than as free ions, hence direct potentiometric measurements provide little information except for major electrolytes such as Fl+, Na+, K+, Cl- and possibly Ca2+, Mg2+. The introduction of ion-selective microelectrodes (e.g. tips < 1 jtm diameter) has allowed these major electrolyte ions to be determined in single cells. 

Tanojo, H., Cullander, C., and Maibach, H.I., Monitoring the permeation of calcium ion across human stratum corneum using an ion-selective microelectrode with high spatial resolution, in Perspectives in Percutaneous Penetration, 6b ed., Brain, K.R. Ed., STS Publishing, Cardiff, 2000. 

Chumbimuni-Torres, K.Y., Dai, Z., Rubinova, N., Xiang, Y., Pretsch, E., Wang, J., and Bakker, E. 2006. Potentiometric biosensing of proteins with ultrasensitive ion-selective microelectrodes and nanoparticle labels. J Am Chem Soc 128(42) 13676-13677. 

Jaramillo et al. published an article regarding some ion-selective microelectrodes used in the analysis of acetylcholine and choline [220]. 

Refs. [i] Amman D (1986) Ion-selective microelectrodes. Springer, Berlin [ii] MorfWE (1981) The principles of ion-selective electrodes and membrane transport. Elsevier... 

Ion-selective microelectrodes can be used to measure ion activities withiii a living organism. 

A2. Ammann, D., Lanter, F., Steiner, R. A., Schulthess, P., Shijo, Y., and Simon, W., Neutral carrier based hydrogen ion selective microelectrode for extra- and intracellular studies. Anal. Chem. 53, 2267-2269 (1981). 

C13. Czaban, J. D., and Rechnitz, G. A., Solid state ion-selective microelectrodes for heavy metals and halides. Anal. Chem. 45, 471-474 (1973). 

H4. Hnik, P., Sykova, E., Kriz, N., and Vyskocil, F., Determination of ion activity changes in excitable tissues with ion-selective microelectrodes. In Medical and Biological Applications of Electrochemical Devices (G. Kortya, ed.), pp. 129-172. Wiley, New York,... 

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