Capillary electrophoresis microseparation technique

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. 

Profile LC Packings is a privately held company based in San Francisco, Amsterdam and Zurich. It was founded in Zurich in 1987 with the goal to develop, manufacture, and commercialize packed microcolumns for use in HPLC. The company offers a complete range of products for use in microseparation techniques such as micro, capillary and nano LC, including electrochromatography, capillary electrophoresis, and LC-MS. 

Capillary electrophoresis is an excellent microseparation technique that has been used for the separation of a wide diversity of different molecules." Its separation capabilities extend to ions, small molecules (such as amino acids), and large biomolecules (such as peptides, proteins, and nucleic acids). Indeed the human genome project owes its success, in part, to the use of CE for the separation of DNA bases. In the past, CE has been combined with detection devices such as ultraviolet (UV) and laser-induced fluorescence (LIE) spectrophotometers. The detection of the separated analytes is carried out on column by etching the capillary. Unfortunately, UV detection lacks sensitivity and not every compound of interest will absorb in the UV region of the spectmm. Detection using LIE is sensitive, however, the analytes of interest may require derivatization with a fluorescent tag or have an aromatic amino acid in their structure (e.g., proteins and peptides). An advantage of MS detection that neither UV nor LIE detection provides is the information necessary to directly determine the structure of the detected analyte(s). 

With the development of microcoil NMR techniques, it is now possible to couple NMR with some microseparation techniques, such as microbore L( 86,93,io3 capillary electrophoresis (CE), and capillary electrochro-matogrphy (CEC), where the inner diameters of the separation channels are in the range of 20 to 75 pm. After coupling these small separation channels with NMR microcoils whose diameters are in the same range, it is possible to achieve maximum mass sensitivity for NMR detec-... 

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