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第37卷 第1期 上海师范大学学报(自然科学版) Vol.37,No.1
2 0 0 8 年 2 月 JournalofShanghaiNormalUniversity(NaturalSciences) 2 0 0 8 , F eb .
C ovalent m odification of carbon electrode
w ith 2-am inoethanethiol and its application
for the trace determ ination of uric acid
ZH A N G Chun-hua, LIA N Ji-ying, ZH A N G Lei
*
( College of Life and E nvironm ent Sciences, Shanghai N orm al U niversity, Shanghai200234, China)
A bstract:
2-A m inoethanethiol (2-A ET ) was covalently grafted on glassy carbon electrode (G CE ) by am ine cation
ra d ica l form ation in the electro-oxidation process of the am ino-containing com pound. The im proved electrochem ical
b eh a vio r o f u ric ac id at th e m od ified elec trode showed thatthe electrode m odified w ith 2 -A E T ex h ib ited efficien t e le c-
tro-catalytic oxidation for uric acid. The anodic overpotential w as reduced about230 m V com pared w ith that obtained
at bare G CE . The enhanced voltam m etric response can be used for the determ ination ofuric acid. The linearcalibra-
tion curve w as obtained over the range from 8.0 ×10
-6
m ol/L to 2.0 ×10
-4
mol/Lwithslop(μA/μM ) an d coeffi-
cient correlation of3.5 and 0.9976, respectively. The detection lim it (3σ) fo r u ric a cid w as 4 . 8 ×1 0
-7
m ol/L. The
relative standard derivation was 2.7% at a concentration of5.0 ×10
-5
mol/L uric acid. The practical utility of the
p rop osed m eth od w as d em onstrated by the m easurem ent of uric acid in h u m an u rin e w ith ou t an y p re lim in a ry trea t-
m ent. M oreover, the catalytic effect of2-A ET /G C E to uric acid led to the voltam m etric resolution of the overlap p in g
oxidation w ave of uric acid and ascorbic acid in a m ixture, w hich allow s the sim ultaneous determ in a tion o f u ric a cid
and ascorbic acid in a sam e sam ple.
K ey w ord s:
2-am inoethanethiol; uric acid; ascorbic acid; covalent m odification
CLC number:
O 657.1
D ocum ent code:
A
ArticleID:
1000-5137(2008)01-0074-08
R eceived date: 2007-09-28
Foundation item : Shanghai M unicipal Education C om m ission(05D Z16) .
Biography: ZH A NG Chun-hua(1982 - ), fem ale, graduate student, College of Life and E nvironm ent Sciences,Shanghai
NormalUniversity; LIA N Ji-ying(1980 - ), fem ale, graduate student, C ollege of Life and Environm ent Sciences,ShanghaiN or-
m alUniversity; ZH ANG Lei(1969 - ), m ale, associate professor, C ollege of Life and E nvironm ent Sciences,Shanghai N orm al
U n iv e r s ity .
* C orresponding author.
1 In tro d u c tion
U ric a c id ( 2 , 6 , 8 -trih y d ro x y p u rin e ) is th e p rim a ry p ro d u c t o f u rin e m e ta b olism and its inconsistency in
hum an body can cause m any diseases, such as gout, hyperuricaem ia and Lesh-N yan disease
[1]
. H ence, the
sim ple and rapid m ethods are necessary to m onitor uric acid in clinical laboratories. H ow ever, the m ajor obsta-
cle in m onitoring uric acid is the interference from other com pounds, especially from ascorbic acid, w hich co-
e x is ts w ith u ric a c id in th e b io lo g ic a l flu id s
[2]
an d can be oxidized at a p otential close to that of uric acid
[3]
.