Kb. Male et Jht. Luong, DETERMINATION OF URINARY GLUCOSE BY A FLOW-INJECTION ANALYSIS AMPEROMETRIC BIOSENSOR AND ION-EXCHANGE CHROMATOGRAPHY, Applied biochemistry and biotechnology, 37(3), 1992, pp. 243-254
A practical biosensor system has been developed for the determination
of urinary glucose using a flow-injection analysis (FIA) amperometric
detector and ion-exchange chromatography. Glucose oxidase was immobili
zed onto porous aminopropyl glass beads via glutaraldehyde activation
to form an immobilized enzyme column. On the basis of its negative cha
rge at pH 5.5, endogenous urate in urine samples was effectively retai
ned by an upstream anion-exchange resin column. The biosensor system p
ossessed a sensitivity of 160 +/- 2.4 RU muM-1 (RU or relative unit is
defined as 2.86 muV at the detection output) for glucose with a minim
um detection level of 10 muM. When applied for the determination of ur
inary glucose, the result obtained compared very well with that of the
widely accepted hexokinase assay. The immobilized glucose oxidase cou
ld be reused for more than 1000 repeated analyses without losing its o
riginal activity. The reuse of the acetate anion-exchange column befor
e replacement would be about 25-30 analyses. Acetaminophen and ascorbi
c acid were also effectively adsorbed by the acetate anion exchanger.
The introduction of this type of anion exchanger thus greatly improved
the selectivity of the FIA biosensor system and fostered its applicab
ility for the determination of glucose in urine samples.