The application of chiral arginine and multi-walled carbon nanotubes as matrices to monitor hydrogen peroxide

Abstract

The enantioselective interaction between horseradish peroxidase (HRP) and arginine enantiomers was investigated by electrochemical methods through studying the electrocatalytic activity of H2O2 biosensor, which was obtained through l-arginine or d-arginine functionalized multi-walled carbon nanotubes (d-Arg-MWCNTs or l-Arg-MWCNTs) immobilizing horseradish peroxidase (HRP) on glassy carbon electrode. Cyclic voltammetric and chronoamperometry were used to characterize the properties of the biosensor. Under the optimal conditions, LAM-CS@HRP/dpAu/GCE biosensor showed better electrocatalytic activity to H2O2 compared to DAM-CS@HRP/dpAu/GCE and MWCNTs-CS@HRP/dpAu/GCE, implying that the different configurations of nanocomposites have different interactions with HRP. The currents of LAM-CS@HRP/dpAu/GCE biosensor had a linear relationship with the concentration of H2O2 in the range of 2.5×10−6 to 2.9×10−3M with a detection limit of 8.3×10−7M (S/N=3). For MWCNTs-CS-HRP/dpAu/GCE electrode, the calibration range of H2O2 was from 6.4×10−4 to 2.9×10−2M and a detection limit of 2×10−5M (S/N=3). For the case of DAM-CS@HRP/dpAu/GCE, there has a linear relationship with the concentration of H2O2 from 1.8×10−5 to 2.6×10−3M and the detection limit is 6×10−5M (S/N=3).