Electrochemical behavior of morphine at ZnO/CNT nanocomposite room temperature ionic liquid modified carbon paste electrode and its determination in real samples

In this paper we report synthesis and application of ZnO/CNT nanocomposite and 1-methyl-3-butylimidazolium bromide as high sensitive sensors for voltammetric determination of morphine using carbon paste electrode. The ZnO/CNT nanocomposite was characterized with different methods such as TEM. SEM and XRD. The electrochemical oxidation of morphine on the new ZnO/CNTs ionic liquid carbon paste electrode (ZnO/CNTs/IL/CPE) was carefully studied. The oxidation peak potential of morphine on the ZnO/CNTs/IL/CPE appeared at 520 mV, which was about 75 mV decrease of the overpotential compared to that obtained on the traditional carbon paste electrode (CPE) and the oxidation peak current was increased for about 5.5 times. The electrochemical parameter of morphine on the ZnO/CNTs/IL/CPE was calculated with the charge transfer coefficient (a). Based on the relationship of the oxidation peak current and the concentration of morphine a sensitive analytical method was established with cyclic voltammetry. The linear range for morphine determination was in the range from 0.1 to 700 mu mol L-1 and the detection limit was calculated as 0.06 mu mol L-1 (3 sigma). Finally, the proposed method was also examined as a selective, simple and precise electrochemical sensor for the determination of morphine in real samples such as urine and ampoule. (C) 2013 Elsevier B.V. All rights reserved.