The particle beam liquid chromatography-mass spectrometry interface, d
eveloped more than ten years ago, has withstood the assault of several
new soft ionization-based interfaces, and it is still largely used wo
rldwide. The particle beam has widened the possibility for many HPLC-a
menable compounds to be ionized under electron ionization conditions w
ithout any appreciable thermal degradation. This feature is not of sec
ondary importance in several ''small'' molecules applications, where t
he analytes can be easily identified and their spectra matched with th
ose collected in literature. The task of separating any solute from a
liquid mobile phase is carried our very efficiently by the particle be
am interface, and the only real limitation is found at the moment of t
he solute vaporization in the ion source; therefore, the principle of
particle formation for sample transfer into a mass spectrometer could
be extended profitably to other ionization techniques. (C) 1997 John W
iley & Sons, Inc.