Flow injection differential potentiometric determination of lysine by using a lysine biosensor

被引:28
|
作者
García-Villar, N [1 ]
Saurina, J [1 ]
Hernández-Cassou, S [1 ]
机构
[1] Univ Barcelona, Dept Analyt Chem, E-08028 Barcelona, Spain
关键词
differential potentiometry; lysine biosensor; ammonium electrode; flow injection analysis; lysine analysis; stopped-flow; partial least squares regression;
D O I
10.1016/S0003-2670(02)01426-5
中图分类号
O65 [分析化学];
学科分类号
070302 ; 081704 ;
摘要
This paper describes a method for the determination of lysine based on a flow injection (FI) differential potentiometry system. The flow injection manifold is composed of a support electrolyte solution channel and a water channel acting as a carrier into which the sample solution is injected. The lysine biosensor was consisted of lysine oxidase chemically immobilized on a nylon membrane and attached to an all-solid-state ammonium electrode. A circular ammonium electrode was used as a reference. Hence, the possible interference of endogenous ammonium can be partly corrected by differential potentiometry. In order to increase the sensitivity of the response, the reaction was kinetically developed following a stopped-flow method. As a result, the sensitivity increased from 20 to 40 mV per decade when comparing the FI and the stopped-flow values. Furthermore, the peak-to-peak stopped-flow signals generated can be used as a more selective analytical response for lysine. The quantification of lysine in mixture samples containing small amounts of ammonium can be achieved with an acceptable accuracy, with prediction errors lower than 4%. However, when the ammonium concentration exceeded the lysine concentration, multivariate calibration with non-linear partial least squares (PLS) regression was needed to improve the lysine quantification, with an overall prediction error around 10%. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
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页码:315 / 324
页数:10
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