Facile preparation of a sensitive electrochemical sensor with good performance for determination of methionine

Abstract

In this work, a novel voltammetric sensor for the detection of methionine was designed and prepared by using a carbon paste electrode (CPE) modified with ZnO hollow quasi-spheres (ZnO hollow QSs) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM.PF6). The results by cyclic voltammetry showed that the prepared electrode (ZnO-BMIM.PF6/CPE) effectively increased the oxidation peak current and reduced the oxidation peak potential of methionine and had a suitable electrocatalytic activity for the oxidation of methionine. Notably, the ZnO-BMIM.PF6/CPE exhibited high detection capability towards the quantification of methionine in 0.1 M PBS (pH 7.0) over a concentration range from 0.04 to 330.0 μM with a limit of detection of 0.02 μM. More importantly, the effectiveness of the ZnO-BMIM.PF6/CPE sensor was also confirmed in real samples (urine detection with acceptable recoveries (98.0 to 102.7%) and relative standard deviation values ≤ 3.3%.