Direct electrochemical detection of Cu(Ⅱ) ions in juice and tea beverage samples using MWCNTs-BMIMPF6-Nafion modified GCE electrodes

•The GCE sensor based on MWCNTs-BMIMPF6-Nafion detected Cu (Ⅱ) ions.•Nafion can significantly improve the easy falling of the modification layer.•The fabricated sensor has excellent anti-interference and stability.•The fabricated sensor determined Cu (Ⅱ) ions in actual food samples. Due to a small amount of Cu (Ⅱ) ions being beneficial and too much being harmful, it is necessary to establish a rapid and direct detection method. Herein, we reported a platform based on multiwalled carbon nanotubes (MWCNTs), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), and Nafion solution-modified glassy carbon electrode (GCE) for the direct electrochemical detection of Cu (II) ions. We used differential pulse anodic stripping voltammetry, including the electrodeposition of Cu (Ⅱ) ions on the modified GCE and subsequent anodic stripping. Under the optimum conditions, the linear range was 20 μg·L−1 ∼ 950 μg·L−1, the limit of detection (LOD) was 16 μg·L−1, and the limit of quantification (LOQ) was 54 μg·L−1 for Cu (II). We realized the quantitative detection of Cu (Ⅱ) ions in juice and tea beverage without tedious pretreatment. The result showed that the sensor had good anti-interference and practicability for actual food samples.