Dusan Milojevic

Investigations of the feasibility of constructing a polypyrrole-mercury/mercury chloride reference electrode

Abstract A polypyrrole-mercury/mercury chloride reference electrode was initially constructed by in situ electropolymerization of pyrrole on a mercury pool anode in a 0.5 M sodium para-toluene sulfonate and 1.0 M sodium chloride mixture solution. However, in this procedure, insufficient amount of mercury was incorporated in the polypyrrole film for reaction with chloride ions to yield a mercury/mercury chloride half cell. Alternatively, a polypyrrole film was galvanostatically deposited on a glassy carbon electrode in the presence of sodium para-toluene sulfonate. Mercury was electrochemically deposited from mercury(I) nitrate at the polypyrrole-coated electrode. The resulting film was deprotonated in 5 M NaOH. Cyclic voltammetry was then carried out in 10 M HCl in order to exchange the para-toluene sulfonate ions with chloride ions and to oxidize mercury for the formation of mercury chloride within the film. A reproducible null potential difference was obtained when the polypyrrole-mercury/mercury chloride electrode was employed as an indicator electrode against a saturated calomel reference electrode in saturated potassium chloride solution.

Toxic interactions between clozapine and ampicillin

Abstract Severe adverse side effects have recently been reported after co-administration of the drugs, ampicillin and clozapine, to a schizophrenic patient. In the present work, conductimetric results indicate that ampicillin and clozapine form a 1:2 charge transfer complex which tends to associate together in water. In contrast, a charge transfer complex with a stoichiometric ratio of 2 moles ampicillin to 1 mole clozapine is obtained when the conductimetric experiment is carried out using acetonitrile as a solvent. Also, the complex appears to dissociate easily in the non-aqueous solution. Nevertheless, in both systems, unexpectedly high capacitance readings were obtained, indicating an adsorption phenomenon of the drugs on electrode surfaces. Further, conductimetric results obtained in water and with Sonification yields a 1:1 ampicillin to clozapine mole ratio. Such results were used to infer the formation of micelles in aqueous solutions. The observed change in stoichiometric ratio of the ampicillin-clozapine complex in aqueous and non-aqueous systems was then used to suggest the action of the drugs on the surface of biomembranes.