Analysis of phenolic compounds catalyzed by immobilized horseradish peroxidase in silica glass

Abstract

Horseradish peroxidases are entrapped into tetramethyl orthosilicate derived silicates by a mild sol–gel process. Compared with free enzymes in solution, silica immobilized Horseradish peroxidases are more robust, stable in a long-term and ease of recycle. Therefore, a phenolic compounds analysis method is established on the immobilized enzyme catalyzed oxidation reaction to produce intensely colored products for spectrophotometric analysis. The absorbance of colored product and analyte concentrations is linearly related. The similar methods also employ on analyzing 2-chlorophenol, 3-chlorophenol and 2,4-dichlorophenol. Furthermore, this method permits to reuse immobilized HRP to examine phenolic compounds. The thin silica film is used as an immobilization carrier. It has shorter pathlength for diffusion of analytes, which will lead to faster response times. Decomposition of quinone-imine colored product also has an effect on accuracy and precision of measurement. Decomposition rate constant is 5.549 × 10−4 min−1. The interference substances have no obvious effect on the analytic results, except for formaldehyde and Pb2+. The proposed method can examine a real sample in waste water.