engleski

Voltametric determination of micro particles of some local anaesthetic and antithusic immobilised on the graphite electrode

Solid micro particles of local anaesthetics cocaine, benzocaine, cinhocaine, lydocaine and procaine, and the antithusic codeine were mechanically immobilised on the surface of the paraffin impregnated graphite electrode and investigated by square-wave and cyclic voltammetry in order to develop a method for their qualitative determination. The measurements were performed in the pH range between 1 and 9. The supporting electrolyte was 1 mol/L KNO3, and the reference electrode was Ag/AgCl/3 mol/L KCl. The square-wave frequency and amplitude were changed between 100 and 800 Hz, and from 15 to 85 mV, respectively. The scan rate in cyclic voltammetry was 1 V/s. The investigated compounds exhibited different electrochemical characteristics that were dependent on the molecular structure and the position of eletroactive groups. The redox reactions of these substances were studied and the minimum surface concentrations of their immobilised micro particles that are required for the reliable analysis were determined. The optimum experimental conditions, such as the frequency, amplitude and pH that ensure the best responses were established for each of the compounds and no mutual interferences were found. The square-wave voltammetry appeared to be more sensitive analytical method than a cyclic voltammetry, but both techniques are fast, simple and selective. The results of these investigations will be used for the fast detection of cocaine in the illegal street powder samples.

square wave voltammetry; cyclic voltammetry; local anaesthetics cocaine; benzocaine; cinhocaine; lydocaine and procaine; codeine

nije evidentirano