Advances in instrumentation in liquid chromatography-mass spectrometry and related liquid-introduction techniques.

In the past few years, the instrumental developments in the field of combined liquid chromatography-mass spectrometry (LC-MS) and related liquid-introduction techniques has been extremely fast. Soon after the demonstration of the ability to obtain multiply-charged ions from proteins by electrospray ionization, a major impetus was given to the field. Numerous LC-MS systems based on atmospheric-pressure ionization sources have now been described. This paper reviews these instrumental developments with reference to currently available commercial LC-MS systems. Not only low and high flow-rate electrospray on quadrupole instrument is discussed, but also electrospray on ion-trap, double-focusing sector, time-of-flight, and Fourier-transform ion-cyclotron resonance instruments are reviewed.