Electrocatalytic Oxidation of Isoproterenol and its Voltammetric Determination in Pharmaceuticals and Urine Samples Using a Poly(1-methylpyrrole)-DNA Modified Electrode

Determination of isoproterenol (ISP) was carried out using a DNA incorporated poly(1-methylpyrrole) modified glassy carbon electrode (GCE). The poly(1-methylpyrrole)-DNA/GCE showed an excellent electrocatalytic effect on the oxidation of ISP. The poly(1-methypyrrole)-DNA/GCE also accelerated the rate of electron transfer reaction of ISP. Compared with a bare GCE, the poly(1-methylpyrrole)-DNA/GCE exhibits a distinct shift of the oxidation potential of ISP in the cathodic direction and a marked enhancement of the current response. A linear calibration plot was obtained covering the concentration range from 2.0 x 10(-6) to 6.0 x 10(-5) M with a detection limit of 1.60 x 10(-7) M by cyclic voltammetry. The electrode system has also successfully resolved the overlapping anodic peak of ISP and uric acid (UA) into two well-defined voltammetric peaks in cyclic voltammetry at 0.416 V and 0.552 V for ISP and UA, respectively. The poly(1-methypyrrole)-DNA/GCE has successfully been utilised for the determination of ISP in pharmaceutical preparations. The validity of the proposed method was also assured by the recovery of ISP and UA in urine samples.