A New Electrochemical Sensor for the Simultaneous Detection of Morphine and Methadone based on Thioglycolic Acid Decorated CdSe Doped Graphene Oxide Multilayers

In this study, an electrochemical sensitive sensor based on thioglycolic acid decorated cadmium selenide (CdSe) doped graphene oxide modified graphite electrode was successfully developed for the simultaneous determination of morphine and methadone. The electrode process was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV).Nanocomposite structure was characterized by FTIR and EDX and XRD. Taguchi’s experimental design method was applied to determine the optimum operating conditions such as pH, bandwidth, scan rate and buffer concentration. And according to the results, pH and buffer concentration were determined as the most effective parameters on the performance of the modified electrode. Under optimized conditions, the calibration curve for methadone presents two linear ranges of current versus analytes concentration in the range of 0.1 to 20 μM and 20 to 323 μM, and 0.05 to 350 μM for morphine, with the detection limits of 0.03μM. For methadone 0.04μM for morphine (3sb / B).The quantification limits, and precision were found to be acceptable. Finally, the developed method was successfully applied for target analytes determination in blood sera taken from different volunteers.