Sensitive detection of haloperidol and hydroxyzine at multi-walled carbon nanotubes-modified glassy carbon electrodes

Haloperidol (i.e. HPD) and hydroxyzine (i.e. HXY), two effective and important tranquilizers with low redox activity, were found to generate an irreversible anodic peak at about +0.86 V ( vs. SCE) or two anodic peaks at about +0.83 and +0.91 V in 0.05 M NaH2PO4-Na2HPO4 (pH= 7.0) buffer solution with a multi-walled carbon nanotubes-modified glassy carbon electrode (i.e. MWNTs/GC), respectively. Their sensitive and quantitative measurement based on the first two anodic peaks was established under the optimum conditions. The anodic peak current was linear to HPD and HXY concentration from 1 x 10(-7) to 2.5 x 10(-5) M and 5 x 10(-8) to 2.5 x 10(-5) M, the detection limits obtained were 8 x 10(-9) and 5 x 10(-9) M, separately. The modified electrode exhibited some excellent characteristics including easy regeneration, high stability, good reproducibility and selectivity. The method proposed was successfully applied to the detection of HPD and HXY in drug tablets and proved to be reliable compared with ultraviolet spectrophotometry. The modified electrode was characterized by electrochemical methods.