Background: Hydrogen peroxide (H2O2) is widely used in various fields and it plays a
quintessential role in a variety of biomolecular processes. H2O2 concentration level is an essential biological
parameter in monitoring and maintaining the physiological balance of a living cell, and its
variation causes some related diseases. Therefore, it is extremely significant to fabricate biosensor
with low cost, which can quickly, accurately and sensitively detect H2O2 in a wide range. The aims
of this paper are to explore a novel electrochemical sensor with high intrinsic peroxidase-like activity,
high sensitivity and stability to effectively detect H2O2 concentration in real samples.
Methods: The chemically modified electrode LaNiTiO3-Fe3O4/GCE was fabricated based on the nanomaterial
LaNiTiO3-Fe3O4 by a simple process, and its electrochemical properties were investigated
in the supporting electrolyte of 0.1 M NaOH by the techniques of cyclic voltammetry and currenttime
curves on an electrochemical workstation with a conventional three-electrode system.
Results: LaNiTiO3-Fe3O4 nanoparticles show good peroxidase-like activity for H2O2 at a low applied
potential of +0.50 V. Under the optimum conditions, the peroxidase biomimetic sensor LaNiTiO3-Fe3O4/GCE exhibited a wide linear response for H2O2 oxidation in the range of 0.05 μM - 3.0 mM (R
= 0.9994) with a high sensitivity of 3946.2 μA·mM-1·cm-2 and fast response time of 2 s; besides, the
detection limit of H2O2 was found to be ca. 5.15 nM (S/N = 3). Moreover, the biosensor exhibited
good repeatability, stability and anti-interference. Satisfactory results were obtained when the sensor
LaNiTiO3-Fe3O4/GCE was applied to determine H2O2 in real samples. All of these results provide
support to practical application.
Conclusion: A highly sensitive peroxidase biomimetic sensor based on LaNiTiO3-Fe3O4 with nanoscaled
material has been successfully explored, and shows good activity for H2O2. The proposed biosensor
with simple and low cost exhibited excellent advantages of quick response, wide linear range,
low detection limit, high sensitivity, long-term stability and good anti-interference ability, which offer