Novel Sensor Based on 3-Mercaptopropyltrimethoxysilane Functionalized Carbon Nanotubes Modified Glassy Carbon Electrode for Electrochemical Determination of Cefixime

In this work, a highly dispersed Multi-walled carbon nanotube (MWCNT) was successfully functionalized with 3-mercaptopropyltrimethoxysilane (MPTS) molecule by silanization method. The MPTS functionalized MWCNT (MPTS-MWCNT) were structurally characterized by scanning electron microscope (SEM) and energy dispersive X-ray (EDAX) techniques. Moreover, glassy carbon electrode modified with MPTS-CNT (MPTSMWCNT/GCE) was prepared by casting of the MPTS-MWCNT solution on GCE. The MPTS-MWCNT/GCE showed an excellent electrocatalytic activity towards cefixime (CEF). Bare GCE shows an ill-defined oxidation wave around 0.95 V for CEF, whereas MPTSMWCNT/GCE shows a well-defined oxidation peak at 0.7 V vs. AgǀAgClǀKCl (3 M). Differential pulse voltammetry method was used to determine CEF in the concentration range of 0.6-20 μM with a detection limit of 0.07 µM (S/N=3). The present modified electrode shows good recovery results for CEF tablet and spiked CEF in human blood plasma sample. Possible interferences, such as: glycine, alanine, ascorbic acid, cephalexine, L-cysteine, glutathione and lysine for the detection of CEF at the MPTS-MWCNT/GCE were investigated. The results showed that L-cysteine and glutathione showed interference, whereas another mentioned compounds did not show interference.