Af. Martin et Ta. Nieman, GLUCOSE QUANTITATION USING AN IMMOBILIZED GLUCOSE-DEHYDROGENASE ENZYME REACTOR AND A TRIS(2,2'-BIPYRIDYL) RUTHENIUM(II) CHEMILUMINESCENT SENSOR, Analytica chimica acta, 281(3), 1993, pp. 475-481
A flow-injection analysis detection method for glucose is presented wh
ich is based on oxidation of glucose by glucose dehydrogenase with con
comitant conversion of NAD+ to NADH followed by chemiluminescent detec
tion of NADH. The glucose dehydrogenase is immobilized via glutaraldeh
yde crosslinking to controlled pore glass to form an immobilized enzym
e reactor. The chemiluminescent reagent, tris(2,2'-bipyridyl)ruthenium
(II) [Ru(bpy)3(2+)] is immobilized in a Nafion film coated on a platin
um electrode to form a regenerable chemiluminescent sensor. The immobi
lized Ru(bpy)3(2+) is oxidized to Ru(bpy)3(2+) which then reacts with
NADH produced by the enzyme reactor to yield light and Ru(bpy)3(2+). R
u(bpy)3(2+) is thus recycled and made available again. Conditions for
optimum enzyme reactor efficiency and chemiluminescent detection are d
etermined and reported for pH (about 6.5), flow-rate (2 ml min-1), and
NAD+ concentration (1-2.5 mM). At the optimum conditions a Working cu
rve is constructed where the upper limit for glucose detection is depe
ndant on NAD+ concentration and lower detection limit is 10 muM glucos
e. Signal reproducibility is 1-2% relative standard deviation. The met
hod is very selective for glucose; some interference is seen from uric
acid, ascorbic acid and catechol as well as species (such as oxalate
and aliphatic amines) already known to chemiluminesce with the Ru(bpy)
3(2+) sensor.