Amperometric and impedimetric characterization of a glutamate biosensor based on Nafion and a methyl viologen modified glassy carbon electrode.
An electrochemical biosensor based on a glassy carbon (GC) electrode chemically modified with the perfluorinated cation-exchange polymer Nafion and methyl viologen (MV) is described. The enzyme was immobilized by cross-linking with glutaraldehyde in the presence of bovine serum albumin (BSA), methyl viologen and Nafion. Operating variables such as the enzyme/BSA ratio, cross-linking time in glutaraldehyde vapor, methyl viologen and Nafion percentages were investigated with regard to their influence on the biosensor sensitivity by using glucose oxidase as the enzyme model due to its high stability and low cost. The glutamate biosensor was elaborated by using optimized parameters and its electrochemical properties were investigated by cyclic voltammetry, amperometry and by electrochemical impedance spectroscopy. The glutamate biosensor shows a detection limit of 20 microM and a linear range extended to 0.75 mM. Its selectivity was tested with 15 different amino acids, each with a concentration of 20 microM, 25 microM acetaminophen, 20 microM uric acid and 200 microM ascorbic acid. No amperometric response was observed for the interfering species. This good selectivity allows glutamate detection in biological media without previous separation of the analyte.
Maalouf
Rita
R
Center of Electrical Engineering of Lyon, CEGELY, UMR/CNRS 5005, Ecole Centrale Lyon, 69134 Ecully Cedex, France.
Chebib
Hanna
H
Saïkali
Youssef
Y
Vittori
Olivier
O
Sigaud
Monique
M
Jaffrezic-Renault
Nicole
N
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002244:Carbon / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D018698:Glutamic Acid / Q000737:chemistry*; D008839:Microelectrodes; D010269:Paraquat / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D020099:Coated Materials, Biocompatible; D005465:Fluorocarbon Polymers; C040402:perfluorosulfonic acid; D018698:Glutamic Acid; D002244:Carbon; D010269:Paraquat