Development and Application of an Efficient Medium for Chromogenic Catalysis of Tetramethylbenzidine with Horseradish Peroxidase

Abstract

The alkylimidazolium tetrafluoroborate ionic liquids (ILs) ([C n mim][BF 4 ] n = 2, 4, 6, 8, 10) and anionic surfactant sodium dodecyl sulfate (SDS) were combined together to produce effective mediums for chromogenic catalysis of tetramethylbenzidine (TMB) with horseradish peroxidase (HRP) in the presence of H 2 O 2 . The chromogenic performance, kinetic behavior, and the possible influencing mechanism for the chromogenic catalysis of HRP-H 2 O 2 -TMB were discussed in detail. Therein, the roles of ionic liquids (ILs) were highlighted by the combination of experiments and theoretical calculations. The SDS/[C 4 mim][BF 4 ] combination displayed superiority in chromogenic catalysis by improving both the substrate solubility and product stability to the maximum extent possible. Furthermore, SDS/[C 4 mim][BF 4 ] combination showed uniqueness for TMB in improving the chromogenic performance compared with other chromogenic substrates of HRP. Inspired by the efficient chromogenic system, an enhanced enzyme-linked immunosorbent assay strategy for the detection of human immunoglobulin G was established and the sensitive colorimetric strategies for the detection of H 2 O 2 and glucose were further developed by employing SDS/[C 4 mim][BF 4 ] combination as the medium of chromogenic catalysis of HRP-H 2 O 2 -TMB. This unique chromogenic system is endowed with multitude of potential applications in biological systems.