Voltammetric Determination of Codeine on Glassy Carbon Electrode Modified with Nafion/MWCNTs

Figure 5

Dependence of the peak current on volume of Nafion/MWCNTs on GC electrode in the range of 0 to 20 μL for 10 μM codeine in 0.1 M phosphate buffer (pH 3.0) and obtained voltammograms for (A) 0; (B) 2; (C) 5; (D) 10; (E) 20 μL Nafion/MWCNTs. Instrumental parameters: = 50 mV, = 5 mV, and , = 20 ms. Preconcentration potential 300 mV, preconcentration time 20 s, and stirring rate 500 rpm.