Monodisperse aerosol generator for use with infrared spectrometry

A system for producing an aerosol beam of solvent-depleted solute with a narrow particle size distribution, which comprises nozzle means for discharging a stable, cylindrical jet of a solution into a confined space, the solution including a relatively volatile solvent with a relatively involatile solute dissolved therein, supply means for supplying the solution to said nozzle means at a rate sufficient to maintain the velocity of the jet at a value that droplet formation occurs, dispersion means for entraining said droplets in a gaseous medium near the point of droplet formation, a desolvating chamber receiving the entrained droplets at one end thereof and having a restrictive outlet spaced sufficiently far from said one end to allow volatilization of said solvent before reaching said restricted outlet, and vacuum means for continuously evacuating gaseous medium, solvent vapor and solvent-depleted solute at high velocity through said restricted outlet to form an aerosol beam of solvent-depleted solute with a narrow particle size distribution while separating off solvent vapor and gaseous medium;

• wherein:
• said desolvating chamber is maintained at about atmospheric pressure;
• and
• said vacuum means includes a vacuum chamber connected to said restricted outlet and a vacuum pump which maintains said vacuum chamber at a pressure in the range of 2-20 torr, a second vacuum chamber and a vacuum pump which maintains said second vacuum chamber at a pressure in the range of 0.01 to 10 torr, skimmer means for separating said beam of solvent-depleted solute from said vacuum chamber first mentioned into said second vacuum chamber, and second skimmer means for separating the beam of solvent-depleted solute from said second vacuum chamber to an infrared spectrometer cell.