Micro-flow in vivo analysis of L-glutamate with an on-line enzyme amplifier based on substrate recycling

Citation
T. Yao et al., Micro-flow in vivo analysis of L-glutamate with an on-line enzyme amplifier based on substrate recycling, ANAL SCI, 17(6), 2001, pp. 703-708
Citations number
18
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
ANALYTICAL SCIENCES
ISSN journal
0910-6340 → ACNP
Volume
17
Issue
6
Year of publication
2001
Pages
703 - 708
Database
ISI
SICI code
0910-6340(200106)17:6<703:MIVAOL>2.0.ZU;2-R
Abstract
A micro-flow enzyme system with a microdialysis probe is proposed for the a mperometric detection of trace amounts of neurotransmitter L-glutamate rele ased from rat brain cells. The L-glutamate oxidase (EC 1.4.3.11)/glutamate dehydrogenase (EC 1.4.1.4) coimmobilized reactor was used to enhance the se nsitivity of L-glutamate as an on-line amplifier based on substrate recycli ng. A poly(1,2-diaminobenzene) film-coated platinum electrode was also used to selectively detect only the hydrogen peroxide generated into a upstream enzyme reactor, without interference from oxidizable species, such as L-as corbate, the adsorption of low molecular-weight proteins in a dialysate, an d NADPH added to the carrier solution to initiate substrate recycling. By t he present in vivo system, L-glutamate was selectively assayed with about a 600-fold increase in sensitivity compared with the unamplified responses. The detection limit was 0.08 mu mol dm(-3). This method was applied to an i n vivo assay of L-glutamate in the extracellular space of rat brain; also, monitoring of the L-glutamate level changed after a continuous stimulation of KCI to demonstrate the reliability of the system.