Nanospray mass spectrometry in protein and peptide chemistry

The introduction of electrospray in the mid-1980s revolutionised biological mass spectrometry, in particular in the field of protein and peptide sequence analysis. Electrospray is a concentration-dependent, rather than a mass-dependent process, and maximum sensitivity is achieved at low flow rates with high-concentration, low-volume samples. This has lead to the development of nanoelectrospray, microelectrospray and related low flow-rate forms of electrospray which offer high sensitivity with low sample consumption. In this chapter the physical chemistry of low flow-rate electrospray is discussed, and a brief review of the types of low flow-rate electrospray interfaces is made. An indication of the performance obtainable on various instruments is given, along with some comments from the author's own experience of these techniques.