E. Pretsch

Lipophilic salts as membrane additives and their influence on the properties of macro- and micro-electrodes based on neutral carriers

Abstract The influence of salts containing lipophilic cations and anions on the electrical resistance of the membranes of calcium ion-selective macro- and micro-electrodes based on a neutral carrier is described. The resistance of macroelectrodes was decreased by a factor of about 50 or of about 3 compared to membranes without and with potassium tetrakis- (p-chlorophenyl)borate, respectively. No significant reduction of the membrane resistance was achieved for microelectrodes. The lower detection limit and the Ca2+/K+ selectivity factor were improved for both types of electrode.

A hydrogen ion-selective liquid-membrane electrode based on tri-n-dodecylamine as neutral carrier

Abstract An electrically neutral hydrogen ion-selective carrier, tri-n-dodecylamine, is used as the active component for liquid-membrane electrodes. The observed ion selectivities are superior to those of previously described pH-sensitive liquid-membrane electrodes. The electrode characteristics permit the study of intracellular as well as extracellular hydrogen ion activities.

Ion sensors: current limits and new trends

The current status of ion sensors in their main application, clinical chemistry, is highlighted. The reasons for the practical success of sensors in this particular area are discussed together with the expected influence of novel technical possibilities for the next generation of clinical ion analyzers. A series of recent research results, including the improvement of lower detection limits, the establishment of selectivities that are much better than reported so far, and new types of reference electrodes will very likely open up numerous new fields of applications of these sensors.

Anion-selective liquid membrane electrodes based on lipophilic quaternary ammonium compounds

SummaryA series of 15 anion-selective membranes, based on quaternary ammonium compounds of different constitution and on a variety of plasticizers in different compositions of the solvent polymeric membranes, lead throughout to the selectivity sequence

Design features of ionophores for ion selective electrodes

ClO_4 - > SCN - > I - > NO_3 - > Br - > Cl - > HCO_3 - \sim OAc - \sim SO_4 ^2 - \sim HPO_4 ^2 - .

General theory of similarity measures for library search systems

. A detailed analysis demonstrates that the selectivity pattern of such systems may be drastically modified only ifa)a mobile, positively charged site with a sufficiently strong and specific interaction with anions is chosen and/orb)an electrically neutral anion-selective membrane component is used.ZusammenfassungEine Reihe von 15 anionenselektiven Membranen, beruhend auf unterschiedlichen quaternären Ammoniumionen und auf verschiedenen Weichmachern, führt auch bei voneinander abweichenden Membranzusammensetzungen durchwegs zur Selektivitätssequenz:

Hypermedia tools for the interpretation of mass spectra

ClO_4 - > SCN - > I - > NO_3 - > Br - > Cl - > HCO_3 - \sim OAc - \sim SO_4 ^2 - \sim HPO_4 ^2 - .