Ion-selective electrodes

Engineering Materials for Electrochemical Sweat Sensing

“…Ideally, variations of potential are only dependent on the interface of sweat/membrane due to potential constants of other interfaces. The activity of target ion can be calculated by measuring potential value on the basis of thermodynamic equilibrium principle and Nernst equation: [ 49 ] Where φ is the measured potential, φ 0 is the potential overall interfaces except the membrane/sweat interface. R , T , F , z , a are, respectively, gas constant, absolute temperature, Faraday constant, charge number of ion, and activity of the target sweat ion.…”

Biosensors and Biofuel Cells

“…The use of ion-selective electrodes has increased enormously over the last few years (Fricke, 1980;Freiser, 1980); their mode of operation and basic principles are well documented Moody and Thomas t 1975;Gammann, 1977). They have been applied successfully to physiological monitoring of blood sodium~potassium, calcium and lithium (Berman, 1974;Zhukov el' aI., 198 t).…”

“…Hydrogen peroxide production may be linked to iodide oxidation , catalysed by molybdate ions Pardue, 1963) or a peroxidase enzyme, allowing the use of an iodine-selective electrode . The use of ion-selective electrodes has increased enormously over the last few years (Fricke, 1980;Freiser, 1980); their mode of operation and basic principles are well documented Moody and Thomas, 1975;Gamrnann, 1977). They have been applied successfully to physiological monitoring of blood sodium, potassium, calcium and lithium (Berman, 1974;Zhukov et al, 1981).…”

“…These two methods have the disadvantage that they are susceptible to interference caused by other ions present in biological samples . This interference may be overcome by the use of gas-sensitive electrodes and air gap electrodes, which have been the subject of excellent reviews serving to describe the study, design and use of gas-sensing electrodes (Bailey and Riley, 1975;Fricke, 1980). Air gap electrodes introduced in the urease assay were later refined for measurements in both serum and whole blood (Hansen and Riaui6ha, 1974), measuring the ammonia evolved upon exposure to strong alkali.…”

Bioselective Membrane Electrode Probes

“…From modest but promising beginnings in the 1940's and 1950's, nuclear magnetic resonance (NMR) spectroscopy has developed into an important research tool (1). Early in its history, NMR spectroscopy was adapted from sole use by physicists, who had first discovered it, to the realm of chemists, who saw the potential of the so-called chemical shift phenomenon as a structural probe.…”