Figure 6. Differential pulse voltammetry (DPV) of SPE/MCNT (---) and DNA (3mg/ml) on SPE/MCNT (- ), potential window 0.4÷1.5 V, pulse amplitude 0.05 V, pulse width 0.05, pulse period 0.5 s, accumulation potential 0.4 V, accumulation time 5 min.