Direct monitoring of pollutants based on an electrochemical biosensor with novel peroxidase (POX1B).
A biosensor for the monitoring of phenolic compounds based on a new protein named POX(1B) purified from garlic which demonstrates similar biochemical properties to peroxidase is investigated. The enzyme was immobilized into chitosan microspheres with covalent link. The properties of the biosensor were analyzed with Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and cyclic voltammetry (CV). FT-IR demonstrates the covalent attachment of POX(1B) into chitosan and SEM shows high dispersion of the POX(1B) into the chitosan microspheres. The redox potential of POX(1B) in chitosan is 147 mV vs. SCE, which is much higher than reported works using HRP, demonstrating excellent direct electrochemical behaviour of the POX(1B). The electrocatalytic activity of the obtained biosensor towards chlorophenols derivatives in a large range from 10 pM to 10 microM was demonstrated. The mediator free POX(1B)-based biosensor exhibited high sensitivity towards 2,6-dichlorophenol, 4-chlorophenol and pentachlorophenol. A detection limit of 1 pM in the case of 4-chlorophenol was demonstrated with kinetic constant K(m,app) of 0.42 microM with high rapidity of electrochemical response of the biosensor of 1 s.
Equipe de Chimie Bioorganique et Bioinorganique, Institut de Chimie Moléculaire et Matériaux d'Orsay, Université Paris-sud, 91405 Orsay, France.
Sarra
S
El Ichi
Mohamed Nejib
MN
Marzouki
Hafsa
H
Korri-Youssoufi
D015374:Biosensing Techniques / Q000379:methods* / Q000706:statistics & numerical data; D048271:Chitosan; D002733:Chlorophenols / Q000032:analysis*; D055664:Electrochemical Techniques; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D004800:Enzymes, Immobilized; D005737:Garlic / Q000201:enzymology; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010084:Oxidation-Reduction; D009195:Peroxidase; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared; D014874:Water Pollutants, Chemical / Q000032:analysis*
D002733:Chlorophenols; D004800:Enzymes, Immobilized; D014874:Water Pollutants, Chemical; D048271:Chitosan; D009195:Peroxidase