Abstract: A monodisperse aerosol generator forms a stable jet of liquid at a velocity allowing columnar breakup into droplets of uniform size and spacing. To prevent degradation of the monodisperse aerosol, it is disposed by entrainment in a high velocity gaseous stream. To provide an interface for direct injection onto a particle collection device or into an infrared or Raman spectrometer or to interface a liquid chromatograph with a particle collection device or an infrared or Raman spectrometer, the generator is followed by a desolvation chamber operation at about atmospheric pressure and a multistage pressure reducer which evacuates solvent vapor and gaseous medium to form a high momentum, solvent-depleted solute aerosol beam which is input into the infrared or Raman spectrometer.