MCR-ALS for Investigating the Effect of Adsorption on the Charging Current; Application for the Voltammetric Determination of Mefenamic Acid on a Glassy Carbon Electrode Modified with MWCNT and Poly L-Proline

This study represents the application of MCR-ALS for the separation of the different sources of variation in a series of the linear sweep voltammograms obtained from the oxidation of the mefenamic acid as a model analyte on a poly L-proline and MWCNT-modified GCE. Two types of faradaic currents including adsorption and diffusion were separated successfully and the effects of the accumulation time and the concentration of mefenamic acid were investigated on the variation of the charging current. The results showed that the contribution of the charging current on the measured signal decreases upon increasing the adsorption as a result of the blockage of the electrode active sites with the adsorbed species which is in agreement with the previous studies. The proposed methodology was employed for the voltammetric determination of mefenamic acid with enhanced figures of merit in real serum samples by removing the contribution of the charging current from the measured signal. The obtained results represent lower detection limit as 90 nM, wider linear range and higher sensitivity compared to the unprocessed and background-subtracted data.