Hydrogen peroxide biosensor based on a myoglobin/hydrophilic room temperature ionic liquid film.
The composite film based on Nafion and hydrophilic room temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium chloride ([bmim]Cl) was used as an immobilization matrix to entrap myoglobin (Mb). The study of ionic liquid (IL)-Mb interaction by ultraviolet-visible (UV-vis) spectroscopy showed that Mb retains its native conformation in the presence of IL. The immobilized Mb displayed a pair of well-defined cyclic voltammetric peaks with a formal potential (E(o)(')) of -0.35 V in a 0.1 M phosphate buffer solution (PBS) of pH 7.0. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide, based on which a mediator-free amperometric biosensor for hydrogen peroxide was designed. The linear range for the determination of hydrogen peroxide was from 1.0 to 180 microM with a detection limit of 0.14 microM at a signal/noise ratio of 3. The apparent Michaelis constant (K(m)(app)) for the electrocatalytic reaction was 22.6 microM. The stability, repeatability, and selectivity of the sensor were evaluated. The proposed biosensor has a lower detection limit than many other IL-heme protein-based biosensors and is free from common interference in hydrogen peroxide biosensors.
Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran. safavi@chem.susc.ac.ir
Afsaneh
A
Safavi
Fatemeh
F
Farjami
D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry / Q000379:methods; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006736:Horses; D006861:Hydrogen Peroxide / Q000032:analysis*; D052578:Ionic Liquids / Q000737:chemistry*; D057230:Limit of Detection; D009211:Myoglobin / Q000737:chemistry*; D010084:Oxidation-Reduction; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013696:Temperature
D005465:Fluorocarbon Polymers; D052578:Ionic Liquids; D009211:Myoglobin; C040402:perfluorosulfonic acid; D006861:Hydrogen Peroxide