Detection of dopamine in the pharmacy with a carbon nanotube paste electrode using voltammetry.

A simply prepared DNA immobilized on a carbon nanotube paste electrode (CNTPE) was utilized to monitor dopamine ion concentration using the cyclic voltammetry (CV) and square-wave (SW) stripping voltammetry methods. The optimum analytical conditions were sought. The result obtained was a very low detection limit compared to other common voltammetry methods. The optimal parameters were found to be as follows: 3.5 pH, 0.48 V SW amplitude, 71 Hz frequency, 5 s accumulation time, 0.01 V increment potential, and -1.3 V (anodic-*-) and 1.2 V (cathodic-o-) accumulation potentials. Given these conditions, the linear working range was observed to be within 0.01-0.11 microg L(-1) (SW anodic and CV). The analytical detection limit was determined to be SW anodic and CV: 4.0 microg L(-1) (2.1 x 10(-11) mol L(-1)) dopamin, and the relative standard deviation at the dopamine concentration of SW anodic 0.05 microg L(-1) was 0.02% (n=15) at the optimum conditions.