A nanobiocompatible composite containing hemoglobin (Hb), ZnO nanoparticles (nano-ZnO) and ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ) was fabricated and further modified on the glassy carbon electrode (GCE). The electrochemical behaviours of Hb in the composite film were carefully studied and a pair of quasi-reversible redox peaks appeared in pH 7.0 phosphate buffer solution, which was attributed to the electrode reaction of Hb heme Fe(III)/Fe(II) redox couple. The presences of nano-ZnO and BMIMPF 6 in the film can retain the bioactivity of Hb and greatly enhance the direct electron transfer of Hb. The immobilized Hb showed high stability and good electrocatalytic ability to the reduction of hydrogen peroxide and O 2 .

In this paper a carbon ionic liquid electrode (CILE) was fabricated by using ionic liquid 1‐ethyl‐3‐methylimidazolium ethylsulphate ([EMIM]EtOSO3) as the modifier and further used as the working electrode for the sensitive anodic stripping voltammetric detection of Pb2+. The characteristics of the CILE were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In pH 4.5 NaAc‐HAc buffer Pb2+ was accumulated on the surface of CILE due to the extraction effect of IL and reduced at a negative potential (‐1.20 V). Then the reduced Pb was oxidized by differential pulse anodic stripping voltammetry with an obvious stripping peak appeared at −0.67 V. Under the optimal conditions Pb2+ could be detected in the concentration range from 1.0 × 10−8 mol/L to 1.0 × 10−6 mol/L with the linear regression equation as Ip(μA) = −0.103 C (μmol/L) + 0.0376 (γ = 0.999) and the detection limit as 3.0 × l0−9 mol/L (3σ). Interferences from other metal ions were investigated and Cd2+ could be simultaneously detected in the mixture solution. The proposed method was further applied to the trace levels of Pb2+ detection in water samples with satisfactory results.