Anodic Determination of Acetylsalicylic Acid at Multiwall Carbon Nanotubes-Epoxy Composite Electrode

A novel electrochemical sensor based on a multiwall carbon nanotube within epoxy composite electrode (MWCNT-EP) has been developed for acetylsalicylic (ASA) detection. ASA is directly determined in 0.1 M Na2SO4 and 0.1 M NaOH supporting electrolytes without the need of a previous time-consuming alkaline hydrolysis step. ASA gives a single irreversible oxidation peak at a potential of + 0.55 V vs. SCE and at + 0.50 V vs. SCE over a wide range of concentrations, respectively.. Linear dependences of the oxidation peak current versus ASA concentrations were achieved using cyclic voltammetry (CV), differential-pulsed voltammetry (DPV), and chronoamperometry (CA). This work demonstrates that MWCNT-EP composite electrode exhibit useful properties for the direct ASA detection characterized by very good analytical parameters, e.g., the sensitivity of 0.081 mA·mM-1 and the lowest limit of detection of 0.004 mM. Also, the relative standard deviation, ranged between 0.5 and 5%, demonstrates a good reproducibility of the sensor.