Electrochemical determination of dopamine using a poly(2-picolinic acid) modified glassy carbon electrode

A poly(2-picolinic acid) chemically modified electrode (CME) for the determination of dopamine (DA) by cyclic voltammetry is described. Compared with a bare glassy carbon electrode, the CME exhibits a 200 mV shift of the oxidation potential of DA in the cathodic direction and a marked enhancement of the current response. In pH 7.0 buffer solution, a linear calibration graph is obtained over the range from 2.5 x 10(-7) to 1.0 x 10(-5) mol dm(-3) with a correlation coefficient of 0.998. The detection limit is 3.0 x 10(-8) mol dm(-3). The modified electrode eliminated efficiently the interference from ascorbic acid (AA) when present in a 150-fold concentration ratio. It also showed excellent stability and reproducibility.