Novel simultaneous determination of fexofenadine and ceftriaxone using pencil graphite electrode modified through iron oxide and graphene oxide/Schiff base layer

Ceftriaxone (Cef) is a well-known antibiotic drug and is used to treat infectious diseases, and fexofenadine (Fex) is an antiallergic and antihistamine drug. Since in a series of diseases such as sinusitis, which is very common, these drugs are usually taken by the patient at the same time, so the simultaneous measurement of these two drugs can be important. In this research, an easy and fast electrochemical method using a modified pencil graphite electrode (PGE) is used to determination of these two drugs simultaneously. Modification of the electrode surface was done by iron oxide layer and graphene oxide (GO) functionalized with 3-aminopropyltriethoxysilane (APTES) and 2-hydroxy-1-naphthaldehyde (GO/Schiff base). The use of iron oxide and GO/Schiff base modifiers increased the sensitivity and selectivity of the electrode. Voltammetry techniques were used to investigation of electrochemical behavior and determination of analytes, and scanning electron microscopy (SEM) images, FTIR spectroscopy, Raman spectroscopy and electrochemical impedance spectroscopy (EIS) were used for characterization of the electrode surface. Several influential factors in improving the measurement and detection of analytes were investigated and optimized. Using the modified electrode in optimal conditions, the calibration curve for Cef and Fex was drawn, the detection limits (DL) of the drugs were obtained as 0.00240 and 0.00015 μM respectively, and the linear range (LR) of measurement was determined as 0.006–5.8 and 0.0007–8.29 μM respectively. Finally, the designed sensor capability was successfully used for the simultaneous determination of Cef and Fex in pharmaceutical samples and biological environments.