This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The direct electrochemistry of glucose oxidase (GOD) entrapped in nano gold particles (NAs)-N,N-dimethylformamide (DMF)-1-butyl-3-methylimidazolium hexafluophosphate (BMIMPF"6) composite film on a glassy carbon electrode (NAs-DMF-GOD (BMIMPF"6)/GC) has been investigated for first time. The immobilized GOD exhibits a pair of well-defined reversible peaks in 0.050M pH 5 phosphate solutions (PS), resulting from the redox of flavin adenine dinucleotide (FAD) in GOD. The peak currents are three times as large as those of GOD-NAs-DMF film coated GC electrode (i.e. NAs-DMF-GOD (water)/GC). In addition, the NAs-DMF-GOD (BMIMPF"6) composite material has higher thermal stability than NAs-DMF-GOD (water). Results show that ionic liquid BMIMPF"6, DMF and NAs are requisite for GOD to exhibit a pair of stable and reversible peaks. Without any of them, the peaks of GOD become small and unstable. Upon the addition of glucose, the peak currents of GOD decrease and a new cathodic peak occurs at -0.8V (versus SCE), which corresponds to the reduction of hydrogen peroxide (H"2O"2) generated by the catalytic oxidation of glucose. The peak current of the new cathodic peak and the glucose concentration show a linear relationship in the ranges of 1.0x10^-^7 to 1.0x10^-^6M and 2.0x10^-^6 to 2.0x10^-^5M. The kinetic parameter I"m"a"x of H"2O"2 is estimated to be 1.19x10^-^6A and the apparent K"m (Michaelis-Menten constant) for the enzymatic reaction is 3.49@mM. This method has been successfully applied to the determination of glucose in human plasma and beer samples, and the average recoveries are 97.2% and 99%, respectively.