Hyphenating liquid phase separation techniques with mass spectrometry: on-line or off-line

The advantages of hyphenating analytical separation techniques to mass spectrometers have been recognised since the 1970s. The first attempts to couple liquid phase separations to mass spectrometry (MS) were problematic, but the development of electrospray ionisation (ES) in 1984 facilitated the production of routinely used, commercial interfaces. This review considers the most recent major developments in hyphenating liquid chromatographic and electrophoretic separations to mass spectrometry, and considers the role the post genomic sciences have played in driving them. It also considers why, despite all of the advances in hyphenation, the future appears to hold a major role for off-line analysis.