Microchip analysis

E. X. Vrouwe, R. Luttge, W. Olthuis and A. van den Berg, Microchip analysis of lithium in blood using moving boundary electrophoresis and zone electrophoresis, Electrophoresis, 26 (2005) 3032-3042. 

Sanders, J.C., Breadmore, M.C., Kwok, Y.C., Horsman, K.M., Landers, J.P., Hydroxypropyl cellulose as an adsorptive coating sieving matrix for DNA separations Artificial neural network optimization for microchip analysis. Anal. Chem. 2003, 75, 986-994. 

Although SGE, CEPS, and microchip analysis are of fundamental importance for genetic analysis, it is important to note that several new promising technologies already exist that allow DNA sequencing without using the classic Sanger biochemistry principle, capillaries, or microchannels (3,17). 

Integration of a dialysis membrane or coupling to a microdialysis probe can help to exclude many of the larger molecules such as proteins that are typically responsible for fouling the sensor elements of microchip analysis systems. The nature of the analysis will dictate whether coupling to a flowthrough or separation-based sensor must be achieved and the kind of detection elements to be employed (optical, electrochemical, etc.). One of the issues with microchip devices is the very small... 

In most cases, the investigator should compare the results of the microchip analysis with those an offline standard technique (CE high-performance liquid chromatography, HPLC) for method validation. Control microdialysate samples must be collected, particularly for in vivo experiments that involve injection of a compound or drug. Such control samples can help identify or eliminate peaks from the microchip analysis. In many cases it is useful to incorporate an internal standard into the sampling process to correct for any changes in the recovery, reaction chemistry or with the on-chip injection process. 

MICROCHIP ANALYSIS OF DNA SEQUENCE BY CONTIGUOUS STACKING OF OLIGONUCLEOTIDES AND MASS SPECTROMETRY... 

The advantages of microchip analysis include the ability to analyze minute samples, speed of analysis, reduced cost and waste, and portability. Ever since, the pTAS has drawn a huge amount of attention, and researchers... 

The microchip analysis format has significant advantages over conventional CE, being 10 times faster... 

Widmer and colleagues in 1990, in which silicon chip analyzers which incorporate sample pretreatment, separation and detection played a fundamental role [9]. The advantages of microchip analysis include the ability to analyze minute samples, speed of analysis, reduced cost and waste and portability. Ever since, the p.TAS has drawn a huge amount of attention and researchers have been attempting to incorporate a microdialysis-based continuous sampling component. Some of the devices which have been fabricated are shown in Fig. 4. 

Tilib SV, Mirzabekov AD (2001) Advances in the analysis of DNA sequence variations using oligonucleotide microchip technology. Curr Opin Biotechnol 12 53-58... 

Kikutani, Y., Hisamoto, H., Tokeshi, M., Kitamori, T, Fabrication of a glass microchip with three-dimensional channel network and its application to a single-chip combinatorial synthetic reactor, in Ramsey, J. M., VAN den Berg, A. (Eds.), Micro Total Analysis Systems, pp. 161-162, Kluwer Academic Publishers, Dordrecht (2001). 

Chen, S.-H., Lin, Y.-H., Wang, L.-Y., Lin, C.-C., Lee, G.-B. (2002). Flow-through sampling for electrophoresis-based microchips and their applications for protein analysis. Anal. Chem. 74, 5146-5153. 

Roddy, E.S., Lapos, J.A., Ewing, A.G. (2003). Rapid serial analysis of multiple oligonucleotide samples on a microchip using optically-gated injection. J. Chromatogr. A 1004, 217-224. 

Sato K, Mawatari K, Kitamori T (2008) Microchip-based cell analysis and clinical diagnosis system. Lab Chip 8 1992-1998... 

Jimidar, M., Van Ael, W, Shah, R., Redlich, D., and De Smet, M. (2003). Fast method development and rapid analysis using a screening approach for enantiomeric separations in capillary electrophoresis./. Capillary Electrophor. Microchip Technol. 8, 101 — 110. 

Two types of conductivity detectors exist the contact conductivity detector, where the electrodes are in direct contact with the electrolyte, and the contactless coupled conductivity detector (C D also called oscillometric detector). With this detector, two stainless-steel tubes that act as electrodes are mounted on a capillary at a certain distance from each other. By applying an oscillation frequency, a capacitive transition occurs between the actuator electrode and the liquid inside the capillary. After having passed the detection gap between the electrodes, a second capacitive transition between the electrolyte and the pickup electrode occurs (see Figures 7 and 8 which is an example of separation of cations). In different reviews, Zemann and Kuban and Hauser discuss the advantages of this technique which include rather simple mechanical parts and electronics, and Kuban et al. compared several C D detectors. This technique has also been used as a detector for analysis by microchip CE. C" D detectors are available to be mounted on existing CE instruments. 

Kuban, P., and Hauser, P. C. (2005). Application of an external contactless conductivity detector for the analysis of beverages by microchip capillary electrophoresis. Electrophoresis 26, 3169—3178. 

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