Highly sensitive simultaneous determination of L-dopa and paracetamol using a glassy carbon electrode modified with a composite of nickel hydroxide nanoparticles/multi-walled carbon nanotubes

The electrochemical oxidation oft-dopa (LD) and paracetamol (PAR) has been investigated by application of nickel hydroxide nanoparticles/multi-walled carbon nanotubes composite electrode (MWCNTs-NHNPs/GCE) using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) methods. The modified electrode showed electrochemical responses with high sensitivity for LD and PAR determination, which makes it a suitable sensor for simultaneous sub-mu mol L-1 detection of LD and PAR in aqueous solutions. Under the optimum conditions the electrode provides a linear response versus LD and PAR concentrations in the range of 0.1-100 mu M and 0.06-26 mu M, respectively using the DPV method. Linear responses versus LD and PAR concentrations in the range of 1-672 mu M and 1-960 mu M, respectively, were obtained using the CA method. The modified electrode was used for determination of LD and PAR in human urine with satisfactory results. (C) 2013 Elsevier B.V. All rights reserved.