Capillary isoelectric focusing with whole column detection and a membrane sample preparation system

Progress of the research on capillary isoelectric focusing (clEF)-whole col umn detection is reviewed. Three kinds of whole column detectors have been developed for cIEF: universal refractive index gradient imaging detector, l aser-induced fluorescence (LIF) imaging detector, and optical absorption de tector. Principle, applicability and detection limit of these detectors are discussed. A capillary column cartridge specially designed for cIEF with w hole column detection is introduced. The column cartridge uses microdialysi s hollow fiber membranes to isolate the sample solution from the electrolyt es. Sample can be directly injected into the column without disturbing the electrolytes using a syringe pump or a liquid chromatography autosampler. T he cartridge incorporates an on-line desalting, carrier ampholytes mixing d evice which also uses a microdialysis hollow fiber membrane. The on-line de vice adapts cIEF to a variety of analytical matrices. Examples of applicati on of different whole column detectors to cIEF are shown in the review. (C) 1999 Elsevier Science B.V. All rights reserved.