Sensitive adsorptive stripping voltammetric determination of paracetamol at multiwalled carbon nanotube modified basal plane pyrolytic graphite electrode

A sensitive electroanalytical methodology for the determination of paracetamol using adsorptive stripping voltammetry (AdsSV) at a multiwalled carbon nanotube modified basal plane pyrolytic graphite electrode (MWCNT-BPPGE) is presented. Both cyclic voltammetric and square wave adsorptive stripping voltammetric techniques are compared. The adsorption occurs at open circuit potential with a 1 min accumulation time. The effect of scan rate and pH were investigated and an optimal scan rate of 100 mV s(-1) and a pH 7.5, 0.05 M phosphate buffer solution (PBS) was used. Additions of paracetamol using cyclic voltammetry exhibits a linear detection range over a wide range of paracetamol concentrations (0.1-25 mu M) with a detection limit of 45 nM (based on 3 sigma). Additions of paracetamol using square wave adsorptive stripping voltammetry show two linear ranges for paracetamol detection. The first linear range is from 0.01 mu M to 2 mu M and the second linear range is from 2 mu M to 20 mu M. Using the first range of this calibration plot, a detection limit of 10 nM is obtained for paracetamol. To the best of our knowledge, this limit of detection is the lowest limit of detection has been reported for paracetamol using electrochemical techniques. The method was then successfully utilised for the determination of paracetamol in a real sample of ANADIN EXTRA tablets and a recovery of 95% was obtained without interference from aspirin or caffeine. The proposed electroanalytical method using MWCNT-BPPGE is the most sensitive method for determination of paracetamol with lowest limit of detection to date. It has also advantages such as easy handling, resistance against surface fouling, and low cost. (C) 2008 Elsevier B.V. All rights reserved.