In this study the electrochemistry of carbidopa (CD) was studied by electrochemical methods at a carbon paste electrode modified by ZnO/CNTs nanocomposite and room-temperature ionic liquid, n-hexyl-3-methylimidazolium hexafluoro phosphate (ZnO/CNTs/ILs/CPE). The oxidation peak potential of the CD at a surface of ZnO/CNTs/ILs/CPE appeared at 570 mV that was about 90 mV lower than the oxidation peak potential at the surface of the unmodified carbon paste electrode (CPE) under similar condition. Under the optimized conditions, the oxidation peak current of CD showed two linear dynamic ranges (in 0.09–450 μmol L−1) with a detection limit of 0.05 μmol L−1, using square wave voltammetry (SWV). The proposed sensor was successfully applied for the determination of CD in real samples such as pharmaceutical serum, water and urine
