ZnO/1-hexyl-3-methylimidazolium chloride paste electrode, highly sensitive lorazepam sensor

The measurement of pharmaceutical compounds in biological fluids is considered an effective way to evaluate their effectiveness. On the other hand, lorazepam is a drug with good efficiency in treatment and some side effects, which measurement is very important. In this study, the ZnO nanoparticle was synthesized as an electrocatalyst by chemical precipitation method. In continuous a simple modification on paste electrode (PE) by ZnO nanoparticle (ZnO-NPs) and 1-hexyl-3-methylimidazolium chloride (HMImCl) was made and new sensor was used for sensing of lorazepam. The HMImCl/ZnO-NPs/PE showed catalytic behavior on oxidation signal of lorazepam and improved its signal about 2.17 times compared to unmodified PE. On the other hand, oxidation signal of lorazepam was reduced about 110 mV at surface of HMImCl/ZnO-NPs/PE compare to unmodified PE that confirm accelerating the electron exchange process after modification of sensor by HMImCl and ZnO-NPs as powerful catalysts. The HMImCl/ZnO-NPs/PE was used for monitoring of lorazepam in water and injection samples and results showed recovery data 98.5 to 103.5 % that are acceptable for a new sensor.