INVITRO MEASUREMENT OF DOPAMINE CONCENTRATION WITH CARBON-FIBER ELECTRODE

Microcomputer-controlled potentiostatic pulse polarization techniques were applied to the analysis of dopamine with carbon fiber electrodes. By the introduction of the electrochemical treatment before every measuring pulse, the sensitivity and reproducibility were remarkably improved. Different carbon fibers gave different stability and sensitivity and HTA-7 was preferred for analytical purposes. The diameter of the electrode was 7 .mu.m. The detection limit was < 2 nM. The separation of dopamine from other catechols and indoles was satisfactory. The adsorption of dopamine at the carbon fiber surface was assumed and the isotherm was discussed.