Sensors based on ruthenium-doped TiO2 nanoparticles loaded into multi-walled carbon nanotubes for the detection of flufenamic acid and mefenamic acid.

Recent advances to utilize two or more nanoparticles for developing novel sensors with superior sensitivity have spurred advanced detection limits even at low concentrations. In this research, a blend of rutheniumdoped TiO2 (Ru-TiO2) nanoparticles and multiwalled carbon nanotubes (MWCNTs) loaded into carbon paste matrix to fabricate a novel Ru-TiO2/MWCNTs-CPE sensor was used for the detection and quantification of flufenamic acid (FFA) and mefenamic acid (MFA) drugs. The surface morphology of Ru-TiO2 was assessed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray diffraction (XRD) and atomic force microscopy (AFM). Sensitivity and selectivity of the electrode was improved at the Ru-TiO2/MWCNTs modified CPE compared to nascent CPE due to the amazing surface distinctive characteristics of the modifier at pH 5.0. The effect of concentration of the modifier, pH, pre-concentration time, sweep rate and concentration on signal enhancement of FFA and MFA was studied. The square wave voltammetry (SWV) currents are linearly related in the concentration range of 0.01 μM-0.9 μM with the detection limit values of 0.68 nM for FFA and 0.45 nM for MFA, respectively. The developed electrode assembly was used for the quantification of both the drug analytes in human urine samples.