Continuous measurement of pentylenetetrazol concentration by a liquid ion exchanger microelectrode

A double-barrelled microelectrode is described, which permits the continuous measurement of the concentration of the epileptogenic agent pentylenetetrazol (PTZ). The electrode is based on the liquid potassium exchanger (Corning No. 477 317) and enables measurements of PTZ concentration in physiological salines down to 1 mM. The electromotive behaviour of the liquid membrane against PTZ cannot directly be described by the Nicolsky-Eisenman formalism. It is suggested that specific interactions of the PTZ molecule with the Corning ligand are involved in the potential generating mechanisms.