This research discusses the preparation of an electrochemical sensor for cephalexin (Ceph) based on multi-walled carbon nanotubes (MWCNT) functionalized with 3-mercaptopropyltrimethoxysilane (MPTS) molecule modified glassy carbon electrode (GCE). The MPTS functionalized MWCNT (MPTS-MWCNT) was structurally characterized by thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). In this area, glassy carbon electrode (GCE) modified with dispersed MPTS-MWCNT ethanol solution on the GCE, which MPTS-MWCNT was used as a new mediator for the voltammetric determination of cephalexin. Differential pulse voltammetry method was employed for determination of Ceph in phosphate buffer solution. Under the optimum conditions at pH 7.00, the oxidation of cephalexin at the surface of the modified electrode was occurred at 1.05 V vs. Ag|AgCl|KCl3M with higher oxidation current in compared to bare GCE. The MPTS-MWCNT/GCE showed an excellent electrocatalysis activity towards oxidation of Ceph. The oxidation peak current of cephalexin at the surface of MPTSMWCNT/GCE in the differential pulse voltammetry are found to be linear over the range of concentration 0.5 to 50 µM and the lower detection limit are found to be 0.12 µM for this drug. The proposed method showed good recovery results for voltammetric determination of Ceph in the Ceph tablet solution and spiked Ceph in human serum sample.
