A modified ultra-high-volume liquid electrostatic aerosol precipitator sampler (LEAP) was calibrated with near monodisperse aerosols of water-soluble and insoluble materials in the size range of 0.02 to 4 microns diameter. The water-soluble materials were ammonium sulfate and ammonium hydrogen sulfate. The insoluble materials included carnauba wax, stearic acid, silver chloride and Y(THD)3. The particulate collection efficiency of the unit ranged from 40 to 98%, depending on particle size, sampling air flow and also on particle material. Tests with water-soluble aerosols showed higher collection efficiency than those with the insoluble aerosols by about 2 to 10%. A sharp decline in the collection efficiency for the particles smaller than 0.1 micron was observed. A comparison with the available manufacturer's data for the particle diameters of 0.1 to 3 microns suggests that the manufacturer overestimated the collection efficiency by 6 to 20% for an air flow of 10 m3/min. We consider the LEAP to be a useful ultra-high volume sampler, especially suited for low-level or short-term sampling.