Tapers and restrictors for capillary electrochromatography and capillary electrochromatography-mass spectrometry

Tapered and narrow restrictor capillaries have been investigated for use in capillary electrochromatography (CEC) and have been shown to offer viable, more reproducible, alternatives to silica frits and may aid in suppression of bubble formation, a recognised problem in CEC. In addition, these capillaries have been coupled to mass spectrometry, especially for low-flow and nano-flow electrospray ionisation, where results have shown better maintenance of chromatographic efficiency and higher sensitivity, compared with more conventional interfaces. The use of tapered CEC column inlets is suggested as being useful in sampling from micro-environments, such as cell contents.