Development of a novel electrochemical sensor modified with graphene oxide/multi-walled carbon nanotubes composite for the analysis of acetaminophen and tramadol in different matrices

In this study, the use of graphene oxide (GO) and multiwalled carbon nanotubes (MWCNTs) as surface modifiers of glassy carbon electrodes (GCEs) is explored for the simultaneous and individual analysis of tramadol and acetaminophen in various matrices. Electrochemical impedance spectroscopy, scanning electron microscopy, and UV spectrophotometry were used to examine GO-MWCNTs/GCE analytical performances. Acetaminophen and tramadol exhibited non-overlapping voltammetric signals at voltages of + 0.59 V and + 0.97 V (vs. Ag/AgCl) in the presence of Britton-Robinson buffer pH 9.0 on the GO-MWCNTs/GCE. Under optimal conditions, the GO-MWCNTs/GCE exhibits linear ranges for acetaminophen and tramadol varying from 2.0 x 10-9 M to 2.45 x 10-4 M and from 1 x 10-9 M to 3.56 x 10-4 M, respectively. The detection limits of acetaminophen and tramadol were 2.5 x 10-10 M and 1.5 x 10-10 M, respectively. The selectivity of GO-MWCNTs/GCE against acetaminophen and tramadol was investigated in the presence of various interferents. The proposed sensor (GO-MWCNTs/GCE) was successfully applied for acetaminophen and tramadol analysis in biological samples and pharmaceutical formulations.