Microseparator

Gavriilidis, a., Yeung, K. L., Design and fabrication of zeolite-based microreactors and membrane microseparators, Micropor. Mesopor. Mater. 42 (2001)... 

X. Zhang, A. G. Webb 2005, (Magnetic resonance microimaging and numerical simulations of velocity fields inside flowcells for coupled NMR microseparations), Anal. Chem., 77, 1338. 

Microseparation of Block Copolymers II Volume Editor Abetz, V. 

Despite the advantages of CEC over CE and HPLC, particle-packed columns are plagued with problems such as the difficulty in the preparation of frits to retain the stationary phase and bubble formation that results in current leakage and EOF breakdown. These problems set the pace for the development of column technology to overcome the problems associated with particle-packed columns and to improve on the speed of separation of analytes in mixtures. The fabrication of a continuous porous rod (monoliths), not requiring any frits and ensuring a constant and uniform current flow to give a stable EOF has so far proved a potential development for microseparations. ... 

The emerging of CEC and the increased scientific work on the preparation of different phases, characterization, and applications of the CEC columns have given much credence to their future potentials in microseparations. The fabrication and availability of different phases for analysis with both particle-packed and monolithic columns give the technique a great future. This is because a variety of mechanisms can be exploited in the analysis and separation of compounds that could otherwise be difficult to analyze with HPLC or CE alone. The ease of coupling CEC to sensitive detectors such as mass spectrometers for enhanced sensitivity, structural elucidation, and characterization bestows the technique with great versatility. 

S. E. Gilbert, The future of liquid-phase microseparation devices in process analytical technology, in Micro Instrumentation for High Throughput Experimentation and Process Intensification - a Tool for PAT, M.V. Koch,... 

Straub et al. (76) reported a method for the identification and quantification of penicillin G, ampicillin, amoxicillin, cephapirin, cloxacillin, and ceftiofur residues in milk using perfusive-particle liquid chromatography combined with ultrasonic nebulization electrospray mass spectrometry. According to this method, a 0.5 ml milk sample is diluted with an equal volume of a solution consisting of acetonitrile/water (1 1), and ultrafiltrated in a microseparation system with a 10000 da molecular mass cut-off filter. An aliquot of the ultrafiltrate is then analyzed on a 15 cm porous II R/H LC (7-8 m) perfusion analytical column using the chromatographic conditions shown in Table 29.3. Concentrations as low as 10 ppb could be readily determined in milk by electrospray mass spectrometric detection. 

Preparative chromatography, which is used on a large scale for the separation and purification of components of a mixture, has progressed into a stand-alone analytical technique with impressive performance, and is now used for microseparation. 

J. Wang, M.P. Chatrathi and B. Tian, Microseparation chips for performing multienzymatic dehydrogenase/oxidase assays Simultaneous electrochemical measurement of ethanol and glucose, Anal. Chem., 73 (2001) 1296-1300. 

Microseparation units make use of the enhancement of mass transport between different phases. PNNL workers reported a microchannel gas-liquid contactor... 

Fruetel, J., Renzi, R., Crocker, R., VanderNoot, V., Stamps, J., Shokair, I., Yee, D., Application of microseparation arrays to the detection of biotoxins in aerosol backgrounds. Micro Total Analysis Systems, Proceedings 5th ytTAS Symposium, Monterey, CA, Oct. 21-25, 2001, 523-524. 

Ultramicroelectrodes can also greatly benefit modem microseparation techniques such as open-tube liquid chromatography or capillary-zone electrophoresis (CZE) (73). For example, cylinder-shaped carbon or copper fibers can be inserted into the end of the CE separation capillary (e.g., see Fig. 3.26). Such alignment of the working electrode with the end of the capillary represents a challenge in combining electrochemistry with CZE. 

Paper chromatograms spot amino acids. Two-dimensional microseparation patterns quickly identify them— or other substances—in a mixture. Added tests give concentrations. Food Ind., 22, 824-951 (1950). 

The aim of this chapter is to cover the theoretical and practical aspects of capillary gel electrophoresis. It also provides an overview of the key application areas of nucleic acid, protein, and complex carbohydrate analysis, affinity-based methodologies, as well as related microseparation methods such as ultra-thin-layer gel electrophoresis and electric field-mediated separations on microchips. It also gives the reader a better understanding of how to utilize this technology, and determine which actual method will provide appropriate technical solutions to problems that may have be perceived as more fundamental. Micropreparative aspects and applications are discussed in Chapter 12. 

RELATED MICROSEPARATION TECHNIQUES USING GELS OR ENTANGLED POLYMER SOLUTIONS... 

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