Electrochemical Biosensor for the Determination of Sufentanil in Human Plasma and Urine based on TiO2 -Graphene Composite modified carbon paste electrode

In this work, the synthesis of TiO2 and graphene nanocomposite modified carbon paste electrode (TiO2-GO/CPE) as an electrochemical biosensor for the detection of sufentanil in human plasma and urine was investigated. The modified Hummers approach was used to synthesize GO nanosheets, and the hydrothermal approach was used to produce TiO2-GO nanocomposite. Due to the interaction of TiO2 nanoparticles with GO, structural studies of the produced nanocomposite using SEM and XRD revealed that TiO2 nanoparticles in anatase structure had been anchored to GO's nanosheets surface. Electrochemical studies using CV revealed that TiO2-GO/CPE had higher electrocatalytic current and lower potential than GO/CPE and CPE for determination of sufentanil due to the synergetic effect of high electrical conductivity of GO nanosheets and intercalation of TiO2 nanoparticles on nanocomposites. The sensitive, stable, and rapid response of TiO2-GO/CPE was demonstrated in amperometric tests for the detection of sufentanil. The limit of detection, sensitivity and linear range for the determination of sufentanil was obtained at 0.07nM, 4.1070μA/μM, and 1 to 10 μM, respectively. The ability of TiO2-GO/CPE as a sufentanil sensor in prepared real samples of urine and human plasma showed that the performance of TiO2-GO/CPE to determine sufentanil in real samples was adequate and acceptable.