Miniaturized capillary electrophoresis system with a carbon nanotube microelectrode for rapid separation and detection of thiols

• Published in: Talanta (Oxford) Vol. 64; no. 4; pp. 1018 - 1023
• Main Authors: Chen, Gang, Zhang, Luyan, Wang, Joseph
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-11-2004; Oxford Elsevier
• Subjects: Amperometric detection; Analytical chemistry; Capillary electrophoresis; Carbon nanotube; Chemistry; Chromatographic methods and physical methods associated with chromatography; Cysteine; Electrochemical methods; Exact sciences and technology; General, instrumentation; Glutathione; Homocysteine; Miniaturization; N-Acetylcysteine; Other chromatographic methods; Carbon nanotube; Amperometric detection; Cysteine; N-Acetylcysteine; Capillary electrophoresis; Miniaturization; Homocysteine; Glutathione; Phosphates; Thiol; Biochemical analysis; Chemical analysis; Stability; Noise; N-Acetlcysteine; Chemical sensor; Carbon; Electrochemical detector; Chemical enrichment; Miniaturisation; Adsorption; Reproducibility; Detection limit; Amperometry; Microelectrode; Separation process
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2004.04.022

Multi-walled carbon nanotube (CNT) was mixed with epoxy to fabricate microdisc electrode used as a detector for a specially designed miniaturized capillary electrophoresis (CE)–amperometric detection system for the separation and detection of several bioactive thiols. The end-channel CNT amperometric detector offers favourable signal-to-noise characteristics at a relatively low potential (0.8
V) for detecting thiol compounds. Factors influencing the separation and detection processes were examined and optimized. Four thiols (homocysteine, cysteine, glutathione, and
N-acetylcysteine) have been separated within 130
s at a separation voltage of 2000
V using a 20
mM phosphate running buffer (pH 7.8). Highly linear response is obtained for homocysteine, cysteine, glutathione, and
N-acetylcysteine over the range of 5–50
μM with detection limits of 0.75, 0.8, 2.9, and 3.3
μM, respectively. Good stability and reproducibility (R.S.D. < 5%) are obtained reflecting the minimal adsorption of thiols at the CNT electrode surface. The new microchip protocol should find a wide range of bioanalytical applications involving assays of thiol compounds.