A novel electrochemical sensor based on ZnO nanoparticle and ionic liquid binder for square wave voltammetric determination of droxidopa in pharmaceutical and urine samples

Synthesis and application of ZnO nanoparticles (Zn/NPs) and 1-butyl-3-methylimidazolium hexafluoro phosphate as high sensitive sensors for voltammetric determination of droxidopa (DXP) using carbon paste electrode has been reported for the first time. The synthesized nanoparticles were characterized by different methods such as TEM, SEM and XRD. The electrochemical oxidation of DXP on the new ZnO/NPs ionic liquid carbon paste electrode (ZnO/NPs/IL/CPE) has been carefully studied. The experimental results suggested that the modified electrode promoted electron transfer reaction for the oxidation of DXP. Under the optimized conditions of pH 7.0, the plot of peak current vs. DXP concentration consisted of two linear segments with slopes of 0.4733 and 0.0177 μA μmol−1 L in the concentration ranges 0.4–5.0 μmol L−1 and 5.0–310.0 μmol L−1, respectively. The detection limit was 0.15 μmol L−1. The proposed method was successfully applied for the determination of DXP in tablet, serum and urine samples.