Graphene nanosheets modified glassy carbon electrode for simultaneous detection of heroine, morphine and noscapine

► Glassy carbon electrode modified with graphene nanosheets (GC/GNSs). ► GC/GNSs was used for electrocatalytic oxidation of morphine, noscapine and heroin. ► DPV technique was used for determination of three important opiate drugs. ► Heroin, noscapine and morphine determined simultaneously or individually. ► Micromolar of these compounds analyzed without any separation or pretreatment steps. In the present study, the graphene nanosheets (GNSs) modified glassy carbon (GC) electrode is employed for simultaneous determination of morphine, noscapine and heroin. To the best of our knowledge this is the first report of the simultaneous determination of these three important opiate drugs based on their direct electrochemical oxidation. Field emission scanning electron microscopy (FESEM) technique is utilized in order to study the surface morphology of the modified electrode. The modified electrode shows excellent electrocatalytic activity toward oxidation of morphine, noscapine and heroin at reduced overpotentials in wide pH range. In the performed experiments, differential pulse voltammetric determination of morphine, noscapine and heroin yields calibration curves with the following characteristics; linear dynamic range up to 65, 40 and 100μM, sensitivity of 275, 500 and 217nAμM−1cm−2, and detection limits of 0.4, 0.2 and 0.5μM at 3SB, respectively. Fast response time, signal stability, high sensitivity, low cost and ease of preparation method without using any specific electron-transfer mediator or specific reagent are the advantageous of the proposed sensor. The modified electrode can be used for simultaneous or individual detection of three major narcotic components, heroin, noscapine and morphine at micromolar concentration without any separation or pretreatment steps.