Microchip capillary electrophoresis

Lin, C. H., Lee, G. B., Fu, L. M., and Chen, S. H. (2004). Integrated optical-fiber capillary electrophoresis microchips with novel spin-on-glass surface modification. Biosens. Bioelectron. 20, 83—90. 

Lu, Q., G. E. Collins, M. Smith, and J. Wang. Sensitive capillary electrophoresis microchip determination of trinitroaromatic explosives in nonaqueous electrolyte following solid phase extraction. Anal. Chim. Acta 469, 253-260 (2002). 

Miniaturised devices electrochemical capillary electrophoresis microchips for clinical application... 

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. 

EC detection is a promising alternative for capillary electrophoresis microchips due to its inherent characteristics, allowing a proper miniaturisation of the devices and compatibility with the fabrication processes, in case of an integrated detection. Moreover, the low cost associated permit the employment of disposable elements. As the EC event occurs on the surface of electrodes and the decrease in size usually results in new advantages (see Chapter 32), the possibilities of incorporating EC detectors are broad. The simplicity of the required instrumentation, portable in many cases, suit well with the scaling-down trend. Moreover, as the sample volume in conventional micro-channel devices is less than 1 nL, a very highly sensitive detector should be constructed to analyse even modest concentrations of sample solutions. Since sensitivity is one of the accepted characteristics of EC detection EC-CE microchips approach to the ideal analytical devices. 

EC detectors have already proven to be well suited for CE microchip systems, and therefore as commented in a recent review of EC detection for capillary electrophoresis microchips by Wang [48], the rapid progress of EC detection for CE microchips over the past six years suggests the major impact it may have in the near future . Other revisions on developments in EC detection for microchip capillary electrophoresis can be found in Refs. [49-51]. 

Ascorbic acid is an important vitamin and its determination is needed not only in foods but also in drugs, blood and urine. Capillary electrophoresis microchips with EC detection allow a simple and rapid detection of ascorbic acid as well as its separation from interferences. 

Miniaturised analytical systems, especially capillary electrophoresis microchips, have demonstrated to be a promising tool for analytical purposes. 

M. Castano-Alvarez, M.T. Fernandez-Abedul and A. Costa-Garcia, Poly(methylmethacrylate) and Topas capillary electrophoresis microchip performance with electrochemical detection, Electrophoresis, 26 (2005) 3160-3168. 

J. Wang, Electrochemical detection for capillary electrophoresis microchips A review, Electroanalysis, 17 (2005) 1133-1140. 

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. 

Y. Du, J. Yan, W. Zhou, X. Yang and E. Wang, Direct electrochemical detection of glucose in human plasma on capillary electrophoresis microchips, Electrophoresis, 25 (2004) 3853-3859. 

J.-H. Kim, C.J. Kang and Y.-S. Kim, A disposable capillary electrophoresis microchip with an indium tin oxide decoupler/amperometric detector, Microelectr. Eng., 78-79 (2005) 563-567. 

R.S. Martin, A.J. Gawron, S.M. Lunte and C.S. Henry, Dual-electrode electrochemical detection for poly(dimethylsiloxane)-fabricated capillary electrophoresis microchips, Anal. Chem., 72 (2000) 3196-3202. 

J. Wang, G. Chen, M. Wang and M.P. Chatrathi, Carbon-nanotube/cop-per composite electrodes for capillary electrophoresis microchip detection of carbohydrates, Analyst, 29 (2004) 512-515. 

J. Wang, G. Chen, M.P. Chatrathi and M. Musameh, Capillary electrophoresis microchip with a carbon nanotube-modified electrochemical detector, Anal. Chem., 76 (2004) 298-302. 

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

A) Design, integration, and alignment of an amperometric detector based on a metal-wire working electrode in a capillary electrophoresis microchip. (B) Evaluation of the amperometric detector and separation/ injection performance. (C) Determination of different parameters for the separation of L-ascorbic acid and hydrogen peroxide using PMMA and Topas CE-microchips. 

Fabrication of capillary electrophoresis microchip by UV-LIGA process... 

Liu, Y., Fanguy, J.C., Bledsoe, J.M., Henry, C.S., Dynamic coating using polyelectrolyte multilayers for chemical control of electroosmotic flow in capillary electrophoresis microchips. Anal. Chem. 2000, 72(24), 5939-5944. 

Wang, J., Chatrathi, M.P., Mulchandani, A., Chen, W., Capillary electrophoresis microchips for separation and detection of organophosphate nerve agents. Anal. Chem. 2001, 73(8), 1804-1808. 

Sirichai, S., de Mello, A.J., A capillary electrophoresis microchip for the analysis of photographic developer solutions using indirect fluorescence detection. Analyst 2000, 125(1), 133-137. 

Sun, X., Yan, J., Yang, X., Wang, E., Electrochemical detector based on sol-gel-derived carbon composite material for capillary electrophoresis microchips. Electrophoresis 2004, 25, 3455-3460. 

Due to its simple optical devices, wide linear range of response and many well characterized CL systems, chemiluminescence (CL) is uniquely suited to on-line detection for /t-TAS. Some reports have shown that CL is an alternative promising detection method for capillary electrophoresis microchip. In the present work, some glass microchips were designed based on the flow injection and electroosmotic flow (EOF)-chemiluminescent devices and applied to determine transition metal ions and organic compounds. 

Fig. 17 Schematic representation of a capillary electrophoresis microchip using a confo-cal epiluminescence microscope as an ultrasensitive detection system to monitor the analytes separated on the separation channel of a CE microchip. (Adapted from Refs. 68 and 454.)...

Alderman,)., O Mathuna, S. C., Eabrication of a miniamrized liquid chromatography separation channel on silicon. J. Capillary Electrophoresis Microchip Technol. 1999, 6(1 2), 33-36. 

Castano-Alvarez, M., Fernandez-Abedul, M. T., and Costa-Garcia, A., Amperometric detector designs for capillary electrophoresis microchips, J. Chromatogr A, 24,1109, 291—299, 2006. 

Liu, J., and Lee, M.L. Permanent surface modification of polymeric capillary electrophoresis microchips for protein and peptide analysis. Electrophoresis, 27, 3533, 2006. 

Ding, Y., Mora, M. R, and Garcia, C. D., Analysis of aUcyl gallates and nordihydroguaiaretic acid using plastic capillary electrophoresis—microchips, AnaZyft c Chimica Acta, 561,126, 2006. 

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