Capillary electrophoresis amperometric detection

Amperometric detection Capillary electrophoresis Conductivity detection Microfluidic chip... 

Sun, X. et al., Capillary electrophoresis with amperometric detection of curcumin in Chinese herbal medicine pretreated by solid-phase extraction, J. Chromatogr. A, 962, 117, 2002. 

For many applications, diode array detection has become routine. A photodiode array was used for simultaneous detection of 100 capillaries in zone electrophoresis and micellar electrokinetic chromatography (MEKC).1516 Deflection of a laser beam by acoustic waves was reported as a means to scan six capillary channels on a microchip.17 The design of a low-noise amperometric detector for capillary electrophoresis has been reported.18... 

Simple etching of the capillary end served to decouple the electrophoretic current from that of amperometric detection, permitting quantitation of attomole levels of catecholamines from brain microdialyzates.24 A postcolumn reactor using bromine generated electrochemically in situ has been used in the detection of peptide thiols, such as glutathione and cysteine, separated by capillary electrophoresis.25... 

Fang, X. M., Ye, J. N., and Fang, Y. Z. (1996). Determination of polyhydroxy antibiotics by capillary zone electrophoresis with amperometric detection at a nickel electrode. Anal. Chim. Acta 329, 49-55. 

Wang, J. and M. Pumera. Dual conductivity/amperometric detection system for microchip capillary electrophoresis. Anal. Chem. 74, 5919-5923 (2002). 

Voltammetry has been adapted to HPLC (when the mobile phase is conducting) and capillary electrophoresis (CE) as a detection technique for electroactive compounds. In this usage, the voltammetric cell has to be miniaturised (to about 1 pi) in order not to dilute the analytes after separation. A metal or carbon microelectrode has a defined potential (vs the reference electrode) depending on the substances to be detected (ions or molecules) and the mobile phase flows through the detection cell (Fig. 19.5). This method of amperometric detection in the pulsed mode is very... 

Figure 26-29 (a) Amperometric detection with macroscopic working electrode at the outlet of the capillary, (b) Electropherogram of sugars separated in 0.1 M NaOH, in which OH groups are partially ionized, thereby turning the molecules into anions. [From J. Ye and R. P Baldwin, Amperometric Detection In CapHary Electrophoresis with Normal Size Bectrodes," Anal. Chem. 1993,65,3525.]... 

The aim of this chapter is to show through the subsequent sections the present trends in capillary electrophoresis microchips paying special attention to the manufacturing and designs employed in those combined to electrochemical (EC) detection. Conductimetric and amperometric detection are considered. Clinical application of these devices is further revised. 

M.J. Schoning, M. Jacobs, A. Muck, D.-T. Knobbe, J. Wang, M. Chatrathi and S. Spillmann, Amperometric PDMS/glass capillary electrophoresis-based biosensor microchip for catechol and dopamine detection, Sens. Actuator B, 108 (2005) 688-694. 

Klett and L. Nyholm, Separation high voltage field driven on-chip amperometric detection in capillary electrophoresis, Anal. Chem., 75... 

W.R. Vandaveer IV, S.A. Pasas, R.S. Martin and S.M. Lunte, Recent developments in amperometric detection for microchip capillary electrophoresis, Electrophoresis, 23 (2002) 3667-3677. 

C. -C. Wu, R.-G. Wu, H.-G. Huang, Y.-C. Lin and H.-C. Chang, Three-electrode electrochemical detector and platinum film decoupler integrated with a capillary electrophoresis microchip for amperometric detection., Anal. Chem., 75 (2003) 947-952. 

J. Vickers and C.S. Henry, Simplified current decoupler for microchip capillary electrophoresis with electrochemical and pulsed amperometric detection, Electrophoresis, 26 (2005) 4641-4647. 

J. Wang, M.P. Chatrathi and B. Tian, Capillary electrophoresis chips with thick-film amperometric detectors Separation and detection of hydrazine compounds, Electroanalysis, 12 (2000) 691-694. 

J. Wang, S. Mannino, C. Camera, M.P. Chatrathi, M. Scampicchio and J. Zima, Microchip capillary electrophoresis with amperometric detection for rapid separation and detection of seleno amino acids, J. Chromatogr. A, 1091 (2005) 118-177. 

There can be found good reviews on conventional and microchip capillary electrophoresis in forensic/security analysis [4 7] in the literature. The aim of this chapter is to overview the progress which has been made towards the development of portable microfluidic device for on-site and fast detection of nitrated explosives and to describe the major developments in this field (summarized details on analytical methods for microchip determination of nitroaromatic explosives can be found in Table 35.2). The corresponding practical protocol for measurements of explosives on microfluidic device with amperometric detector is described in Procedure 49 (see CD accompanying this book). 

Separation and amperometric detection of hydrogen peroxide and L-ascorbic acid using capillary electrophoresis microchips... 

Baldwin, R.P., Electrochemical determination of carbohydrates Enzyme electrodes and amperometric detection in liquid chromatography and capillary electrophoresis. J. Pharm. Biomed. Anal. 1999, 19, 69-81. 

Figure 3.24 Capillary electrophoresis/amperometric response of a Bud Light beer sample using different detection potentials. (Reproduced with permission from Ref. 72.)...

Kappes et al. evaluated the potentiometric detection of acetylcholine and other neurotransmitters through capillary electrophoresis [209]. Experiments were performed on an in-house capillary electrophoresis instrument that made use of detection at a platinum wire, dip-coated in 3.4% potassium tetrakis (4-chlorophenyl) borate/64.4% o-nitrohenyl octyl ether/32.2% PVC in THF. The results were compared to those obtained using capillary electrophoresis with amperometric detection at a graphite electrode. Samples prepared in the capillary electrophoresis buffer were electrokinetically injected (7 s at 5 kV) into an untreated fused silica capillary (88 cm x 25 pm i.d.) and separated with 20mM tartaric acid adjusted to pH 3 with MgO as the running buffer. The system used an applied potential of 30 kV, and detection versus the capillary electrophoresis ground electrode. 

Amperometric detection, which generally offers quite high sensitivity, has not been used so far for forensic (toxicological) applications. The reason probably reflects some problems with commercially available coupling of the high-performance amperometric cell with the capillary electrophoresis device. 

Figure 12.9. Amperometric CE detector with cathodic insulating assembly and ultramicroelectrode.7 [Reprinted, with permission, from R. A. Wallingford and A. G. Ewing, Anal. Chem. 60 (No. 3), 1988, 258-263. Amperometric Detection of Catechols in Capillary Zone Electrophoresis with Normal and Micellar Solutions . 1988 by American Chemical Society.]...

Holland LA, Leigh AM. Amperometric and voltammetric detection for capillary electrophoresis. Electrophoresis 2002 23 3649-58. 

Hilmi, A., J.H.T. Luong, and A.-L. Nguyen. 1997. Application of capillary electrophoresis with amperometric detection to study degradation of chlorophenols in contaminated soil. Environ. Sci. Technol. 31 1794-1800. 

B Yang, J Mo, X Yang, L Wang. Separation and determination of chlorphenamine maleate, acetaminophen and vitamin C of cold medicines by capillary electrophoresis with amperometric detection. Sepu 17 477-479, 1999. 

Fu, C. G., Fang, Z. L., Combination of flow injection with capillary electrophoresis Part 7. Microchip capillary electrophoresis system with flow injection sample introduction and amperometric detection. Anal. Chim. Actfl 2000,422(1), 71-79. 

HA, heterocyclic amine AA, aromatic amine PA, polyamine Al, aliphatic amine N, nitrosamine CZE, capillary zone electrophoresis MEKC, micellar electrokinetic capillary chromatography LIE, laser induced huorescence ED, electrochemical detection CD, conductivity detection AD, amperometric detection PD, potentiometric detection ALA, alkylamines AQA, alkyl and aUcylbenzyl quaternary ammonium compound A, air H, water S, soil W, waste. 

---