University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Juice

Classification: Fruit -> peach -> juice

Citations 1

"A Multisyringe Flow Injection System With Immobilized Glucose Oxidase Based On Homogeneous Chemiluminescence Detection"
Anal. Chim. Acta 2004 Volume 508, Issue 1 Pages 23-30
Matías Manera, Manuel Miró, José Manuel Estela and Víctor Cerdà

Abstract: In this paper, enzyme containing reactors are for the first time implemented in the multisyringe flow injection analysis (MSFIA) technique interfaced with chemiluminescence detection for biochemical assays. The automated methodology is based on the on-line substrate conversion in an oxidase packed-bed reactor and the post-column chemiluminogenic catalyzed-reaction of the generated oxidising species with an organic molecule (namely, 3-aminophthalhydrazide) in front of the photosensor module. Various catalysts in homogeneous phase are compared taking advantage of the benefits of the MSFIA concept. On one hand, mineral catalysts (namely, Co(II)) are assessed, on the other hand, minute and accurate volumes of soluble organic species (viz., horseradish peroxidase (HRP)) are readily handled without requiring further immobilization protocols. The potentials of the MSFIA-CL concept with immobilization of the proper oxidase protein are demonstrated using glucose as a model of substrate. Despite the different pH and kinetic requirements for both the substrate conversion in the enzyme-reactor and the Co(II)/HRP-mediated luminol oxidation integrated in the flow system, the MSFIA approach warrants maximum yields owing to the independent optimization of the physical and chemical parameters of the various reactions involved. Under the optimized configurations and experimental variables, dynamic working ranges from 2.5 x 10^-6 to 1.0 x 10^-3 mol L-1 glucose may be obtained for both detection schemes by proper photomultiplier gain selection. The detection and determination limits calculated at the 3s and 10s level were 8.6 x 10^-7 and 2.0 x 10^-6 mol L-1 glucose, respectively, for the Co(II)-luminol system, and 1.3 x 10^-6 and 2.3 x 10^-6 mol L-1 glucose, respectively, for the HRP-luminol procedure. The repeatability (n=10) at the 1.0 x 10^-5 mol L-1 level was slightly better for the Co(II)-catalyzed reaction (2.5% versus 4.0%). The developed MSFIA-CL methodology was used for kinetic studies of the mutarotation reaction between α and β anomeric forms of glucose, obtaining quantitative information of the specific glucose oxidase (GOD) anomer formed at prefixed intervals of time. It was also successfully applied to the determination of traces of glucose in complex matrices, namely, human urine, soft drinks and fruit juices, exploiting the Co(II)-mediated luminol oxidation.
Glucose Chemiluminescence Multisyringe Interferences Immobilized enzyme Optimization Column