The renewable glassy carbon annular band electrode in a highly sensitive normal pulse voltammetric determination of paracetamol with continuous wavelet transformation

This work describes a novel working electrode - the renewable glassy carbon annular band electrode (R-GC-ABE). The strategy to create the R-GC-ABE is based on the mechanical removal of solid and gas contaminants and electrochemical activation in the electrolyte which fills the electrode body. The main constituents of the R-GC-ABE: a specially constructed glassy carbon annular band electrode, a silver wire used as silver counter/quasi-reference electrode and a silicon O-ring are fastened together in a polypropylene body. The R-GC-ABE was constructed and evaluated as a sensor for determination of paracetamol (PAR) by differential pulse (DP) and normal pulse (NP) voltammetry. Also a signal processing algorithm which utilizes continuous wavelet transform was described and applied for transformation of the sigmoidal-shaped NPV signals - to the peak-shaped curves. In the effect, the new strategy of PAR determination is 32 times more sensitive than DPV technique. The repeatability is below 2-3% (n=3) for the 0-50 mg L-1 concentration range of PAR. The detection limit is 4 mu g L-1 with sensitivity of 2.75 +/- 0.04 mu A/mg L-1. The correlation coefficient is equal to 0.9990. The proposed method was successfully applied for determination of PAR in commercial tablets and in spiked human urine (CRM). The obtained results show substantial improvement of the performance of R-GC-ABE electrode and NPV technique. (C) 2013 Elsevier Ltd. All rights reserved.