A novel chemically modified electrode is constructed based on a multi-walled carbon nanotube (MWCNT), nickel hydroxide nanoparticle (NHNP) and Mobil catalytic material number 41 (MCM-41) composite modified glassy carbon electrode (MWCNTs–NHNPs–MCM-41/GCE). It is demonstrated that the sensor can be used successfully for the simultaneous determination of levodopa (LD), paracetamol (PAR) and tryptophan (TRY). The measurements were carried out by the application of differential pulse voltammetry (DPV), cyclic voltammetry (CV) and chronoamperometry (CA) methods. Under the optimum conditions the electrode provides linear response versus concentration with detection limits of 0.15 μM for LD, 0.01 μM for PAR and 0.11 μM for TRY using the DPV method.
