Determination of Choline in Milk, Milk Powder, and Soy Lecithin Hydrolysates by Flow Injection Analysis and Amperometric Detection with a Choline Oxidase Based Biosensor
详细信息 查看全文
- 作者：Sandra Pati ; Maurizio Quinto ; Francesco Palmisano ; and Pier Giorgio Zambonin
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2004
- 出版时间：July 28, 2004
- 年：2004
- 卷：52
- 期：15
- 页码：4638 - 4642
- 全文大小：67K
- 年卷期：v.52,no.15(July 28, 2004)
- ISSN：1520-5118
文摘
A fast-response and interference-free amperometric biosensor based on choline oxidase immobilizedonto an electropolymerized polypyrrole film for flow injection determination of choline in milk, milkpowder, and soy lecithin hydrolysates is described. The sensor displayed an Imax value of 1.9 ± 0.2
A and an apparent Michaelis - Menten constant, k'M, equal to 1.75 ± 0.07 mM. Detection limits of0.12 M could be obtained. Because even a slight deterioration of the anti-interference membranecan adversely affect measurement accuracy, a real time monitoring of the biosensor selectivity hasbeen achieved by a dual Pt electrode flow-through cell where the enzyme modified electrode is coupledto an enzyme-free electrode in a parallel configuration. Finally, bracketing technique (alternateinjections of sample and standards) allows a two-point calibration to be performed in real-time,correcting for any drift in sensor response.Keywords: Choline; milk; milk powder; soy lecithin; amperometric biosensors; polypyrrole
A and an apparent Michaelis - Menten constant, k'M, equal to 1.75 ± 0.07 mM. Detection limits of0.12 M could be obtained. Because even a slight deterioration of the anti-interference membranecan adversely affect measurement accuracy, a real time monitoring of the biosensor selectivity hasbeen achieved by a dual Pt electrode flow-through cell where the enzyme modified electrode is coupledto an enzyme-free electrode in a parallel configuration. Finally, bracketing technique (alternateinjections of sample and standards) allows a two-point calibration to be performed in real-time,correcting for any drift in sensor response.Keywords: Choline; milk; milk powder; soy lecithin; amperometric biosensors; polypyrrole