Mária Horváth

Zinc Selective Ionophores for Potentiometric and Optical Sensors

Abstract Iminodiacetamide derivatives were synthesized and studied as ionophores in plasticized poly(vinyl chloride) membranes with potentiometric and optical transduction. The N-benzyl and N-phenyl derivatives proved to have a distinct zinc selectivity preferring Zn2+ over Ca2+, Na+ by factors of 6×105 and 3×104. respectively. All ionophores exhibit a serious proton interference (log KPot Zn ++, H + - 6) which suggests that all application of this type of ionophores based sensors are limited to hydrogen ion buffer solution at pH ≥ 6.

Novel bis (crown ether)-based potassium sensor for biological applications

Based on structure-selectivity studies on bis-benzo-crown ether derivatives, 2,2′-bis[3,4-(15-crown-5)-2-nitrophenylcarbamoxymethyl]tetradecane (BME-44) was designed and synthesized. The performance characteristics of this new, highly lipophilic ionophore of the group of bis-nitrobenzo-15-crown-5 derivatives with urethane linkage when used in liquid membrane electrodes are evaluated with special regard to the requirements of biological and clinical applications. Potentiometric steady-state and flow-through dynamic data are presented to prove the sensor capabilities for clinical and physiological potassium determinations.

Novel bis-crown-ether derivatives for potassium sensors

Abstract A variety of bis-benzo-15-crown-5 derivatives were designed and studied with the aim of developing potassium sensors of biological relevance. the significant advantages of bis-/o-nitrophenyl/urethanes have been explained by the existence of NO2-NH hydrogen bonds proved indirectly. the performance characteristics of the prime ligands based sensors were compiled together with potassium assays in biological matrices.

Bis-crown ether derivatives as ionophores for potassium selective electrodes

ZusammenfassungDie Beziehung zwischen der chemischen Struktur und der potentiometrischen Ionen-Selektivität einer neuen Gruppe von Bis-Kronenether-Derivaten wurde eingehend untersucht. Es ergab sich, daß bei Bis-benzo-15-krone-5-Derivaten mit einer Urethanbindung die NO2-Substitution an beiden Benzolringen für die potentiometrische Effektivität von großer Bedeutung ist. Hinweise werden gegeben zur Interpretation der Selektivitäts-steigernden Wirkung des NO2-Substituenten. Die Leistungsfähigkeit der neuen Elektroden auf Ligandenbasis wird mit der von üblichen K-selektiven Sensoren verglichen.SummaryThe correlation between the chemical structure and potentiometric ion-selectivity of a new group of biscrown ether-derivatives has been studied in detail. It was concluded that with bis-benzo-15-crown-5 derivatives with a urethane linkage, NO2-substitution on both benzene rings is of utmost importance with respect to potentiometric performance. Hints have been given for the interpretation of the selectivity increasing effect of the NO2-substituent. The performance characteristics of the new ligand based electrodes were compared with those of the existing potassium selective sensors.

NEW DIRECTIONS IN THE RESEARCH OF SOLVENT-POLYMERIC MEMBRANES

ABSTRACT Efforts have been set to clarify the effect of each membrane component on the electrical and electrochemical properties of liquid membrane electrodes, thus: – different bis-benzo-crown ether derivatives were synthesized and studied in order to have information on the structure -selectivity relationship; – the site concentrations of individual membrane components were determined; – the ion-exchange capacity of membranes of different compositions were studied. In order to study the membrane-solution system in its complexity, impedance and in situ FTIR-ATR studies were planned and carried out. The interfacial and membrane bulk processes were monitored with both electrochemical and the molecular specific IR technique. The spectroscopic data in the light of the electrochemical results offered new possibilities in the interpretation of the electrode response function. These mechanistic studies of solvent-polymeric membranes have proved the role of the membrane components on the membrane bulk and surface processes. On this basis a task-oriented design of ion-selective membranes can be realized.