[Selective determination of dopamine in the presence of high concentration of ascorbic acid with L-cysteine modified glassy carbon electrodes].
摘要
OBJECTIVE: To establish an assay system for determination of dopamine (DA) in the presence of ascorbic acid (AA) with L-cysteine modified glassy carbon electrode. METHODS: L-cysteine was modified onto glassy carbon electrode electrochemically, and with this modified electrode, dopamine was determined by linear sweep stripping voltammetry. RESULTS: L-cysteine polymer-modified electrode had strong catalytic effect towards the electrochemical oxidation of DA. The modified electrode showed good properties in determination of DA with coexisting AA. Under selected conditions, the linearity of DA was in the range of 2.0 x 10(-7) - 1.0 x 10(-4) mol/L with the detection limit of 2.0 x 10(-8) mol/L. The stability, reliability and recovery of this L-cysteine-modified electrode based on electrochemical method were also satisfactory. CONCLUSION: L-cysteine-modified electrode can avoid the interference by AA for determination of DA.