Determination of paracetamol based on electropolymerized-molecularly imprinted polypyrrole modified pencil graphite electrode

Preparation of a molecularly imprinted polymer (MIP) film and its recognition property for paracetamol are investigated. The polypyrrole (PPy) film was prepared by the cyclic voltammetric deposition of pyrrole (Py) in the presence of a supporting electrolyte (LiClO4) with and without a template molecule (paracetamol) through on a pencil graphite electrode (PGE). The performance of the imprinted and non-imprinted (NIP) films was evaluated by differential pulse voltammetry (DPV). Several important parameters controlling the performance of the PPy was investigated and optimized. The molecularly imprinted film exhibited a high selectivity and sensitivity toward paracetamol. The calibration curve for the DPV peak current observed for paracetamol oxidation versus paracetamol concentration at MIP electrode shows two linear regions. The first region demonstrates linearity over a concentration range of 5 mu M to 0.50 mM with a correlation coefficient of 0.996. The slope of the second linear region was smaller than the first region's slope with a wide concentration range of 1.25-4.5 mM (R-2 = 0.990). The detection limit (3 sigma) of paracetamol is 7.9 x 10(-7) M (S/N = 3). Molecularly imprinted polypyrrole modified pencil graphite electrode showed a stable and reproducible response without any influence of interferents commonly existing in pharmaceutical samples. (c) 2007 Elsevier B.V. All rights reserved.