SIMULTANEOUS DETECTION OF THIOLS AND DISULFIDES BY CAPILLARY ELECTROPHORESIS ELECTROCHEMICAL DETECTION USING A MIXED-VALENCE RUTHENIUM CYANIDE-MODIFIED MICROELECTRODE
Jx. Zhou et al., SIMULTANEOUS DETECTION OF THIOLS AND DISULFIDES BY CAPILLARY ELECTROPHORESIS ELECTROCHEMICAL DETECTION USING A MIXED-VALENCE RUTHENIUM CYANIDE-MODIFIED MICROELECTRODE, Journal of chromatography, 680(1), 1994, pp. 271-277
Thiols and disulfides are separated and detected by capillary electrop
horesis-electrochemical detection using a mixed-valence ruthenium cyan
ide-modified microelectrode. A carbon fiber array microelectrode was e
mployed to maximize the signal-to-noise ratio. Detection limits for gl
utathione disulfide, cystine and homocystine were 2.5, 1.3 and 1.1 fmo
l, respectively. The response for cystine was linear over two orders o
f magnitude with a correlation coefficient of 0.992. The long-term sta
bility and overall reproducibility of the electrode were investigated
and found to be highly dependent on the cation concentration in the el
ectrophoretic buffer. The selectivity of this technique for disulfides
was demonstrated by the detection of cystine in the urine of a patien
t with kidney stones.