Recent advances in IEF in capillary tubes and microchips.

The methodological advancements in CIEF in tubes and microchips during the period between 2002 and early 2008 are reviewed as a continuation of previous review by the same author (Electrophoresis 2002, 23, 3847-3857). After a brief introduction, the following topics related to CIEF technologies are addressed: the materials used to form capillary tubes and chips; modes of CIEF related to the detection schemes; coatings of the capillary walls; additives to the separation media; sample-loading methods; development of pI markers and their use; focusing time in relation to the length of the pH gradient; resolution in terms of a peak capacity; and, the reproducibility and precision of CIEF. Three principal detection methods are examined, i.e. ultraviolet absorption, fluorescence and MS. The coupling of CIEF with other electrokinetic separation methods and chromatography is discussed, including many multidimensional systems constructed for proteome analysis using mass spectrometric identification. The developments in the separation of non-covalent complexes and microorganisms are examined. After a short conclusion, this review ends with 176 references.