Improving Electrochemical Performance of Polypyrrole Coating by Graphene Oxide-Carbon Nanotube and Zinc Oxide Nanorods in the Role of a Sensor for the Simultaneous Measurement of Morphine and Methadone

The current research examines the designation of an electrochemical sensor for the simultaneous measurement of morphine and methadone using graphene oxide /multi-walled carbon nanotube/zinc oxide nanorods/polypyrrolenanocomposite, coated on the surface of the graphite electrode reinforced by a hollow fiber.Its performance was investigated by voltammetry methods while the nanocomposite structure was confirmed by FTIR, EDX, XRD, and SEM techniques.To optimize the effectual factors, the Taguchi test designing method with L۲۷(۳x۷) orthogonal array was applied. Thevoltammetricanalysisshowed that two irreversible oxidation peaks appeared at the potentials of ۰.۸۱ V and ۰.۴۱ V for methadone and morphine, respectively. Furthermore, the electrochemical investigations showed that the oxidation process of morphine and methadone wasunder the control of the diffusion phenomenon and two electrons and two protons had been exchanged on the surface of the electrode for bothanalytes. Chronoamperometry was used to measure the diffusion coefficients of drugs which were found for morphine and methadone to be ۵.۳۱×۱۰-۶ cm۲s-۱ and ۱.۱۹×۱۰-۶ cm۲ s-۱. Under optimal conditions, for morphine, two linear concentration ranges of ۰.۰۴-۱۰ μM and ۱۰.۰-۱۰۰ μM and a detection limit of ۰.۰۱ μM were noted whereas for methadone, two linear ranges were observed in ۰.۰۶-۸.۰ μM and ۸.۰-۱۰۰ μM and the detection limit was ۰.۰۲ μM. The designed sensor can be well used for the simultaneous measurement of the drugs with relative recovery percentages in the range of ۹۸.۸۰-۱۰۰.۲۲%for morphine and in the range of ۹۸.۱۴-۱۰۰.۵۸% for methadone.

کلیدواژه ها:

narcotic drugs ، RGO-MWCNT with ZnO in PPy ، Electrochemistry sensor ، biological samples