the electrochemical behavior of nifedipine (i), nitrendipine(ii) and their photodegradation products has been studied by employing electrochemical techniques in chloroform and in 1:4 mixture of chloroform-isopropanol using piperidinium perchlorate (ppc) as supporting electrolyte. it has been shown that i and ii undergo in a 4e, 4h+ irreversible reduction reaction, while the reduction product, p...

Kalman filtering was applied to the current vs. time data obtained at the growing mercury drop of a DME under d.c. polarographic conditions, to separate the faradaic and capacitive components of the electrode current. Polarograms consisting of the pure faradaic current vs. applied d.c. potential were subjected to a four-parameter curve-fitting procedure to obtain the polarographic characteristi...

An approximate but general theoretical treatment for reversible and irreversible stripping polarographic systems is presented. The treatment is based on the development of an average current (i), which at plating times exceeding 15 s. is analogous to the instantaneous current in d-c. polarography. Plots of i vs. (E E*) are generated for reversible and irreversible waves and are discussed for th...

Adsorption effects in square-wave and d. c. polarography of berberine are investigated in the supporting electrolytes of various pH. Tensametric a. c. and SW polarographic measurements show that both berberine and canadine are strongly adsorbed in the potential range between -0.3 V and --'1.7 V vs. SCE. The reduction of berberine proceeds from the adsorbed state and requires four electrons. The...