PREDICTION AND EXPERIMENTAL-DETERMINATION OF SOLUTE OUTPUT FROM A COLLISON NEBULIZER

The total output from a nebulizer is made up of aqueous droplets conta ining solute and a significant component of water vapor. The solvent l oss is reflected in an increase in the nebulizer solution concentratio n over time and this has been described mathematically. This theory, o riginally described by Mercer et al., was modified to describe the sol ute output from a three-jet Collison nebulizer. The influence of conce ntration, air flow (air pressure), volume, and temperature on the outp ut parameters were then studied. Inlet air pressures were 10(4.1), 20 (6.4), and 40 (10.0) psig (L/min), starting concentrations were 0.1, 2 , and 5% (w/w) and initial solution volumes were 10 and 20 mt. To stud y temperature effects, solutions were nebulized at fixed temperatures ranging from 4 to 50 degrees C. This was achieved by water-jacketing t he nebulizer flask. Test solutions consisted of mannitol and a fixed c oncentration of 11.1 mu g/mL carboxyfluorescein. Nebulization was carr ied out for up to 30 min using dry, filtered air at ambient temperatur e. Total output was determined gravimetrically while solute output was determined by fluorimetry (495-nm excitation, 515-nm emission). Solut ion concentration changes were also monitored over time by fluorimetry . The results show that the solution and solvent output parameters are independent of concentration, volume, and air flow within the ranges studied but that solvent output, in particular, is highly dependent up on temperature.