Nebulizer diagnostics: fundamental parameters, challenges, and techniques on the horizon - Invited lecture

Nebulizer diagnostic techniques provide fundamental information for the quantitative assessment and prediction of the quality of the aerosol used for plasma spectrometry. Recent advances in aerosol diagnostic techniques are reported, with an emphasis on micronebulizers used in inductively coupled plasma spectrometry. The qualities of an ideal nebulizer in generating an analytically ideal aerosol for plasma spectrometries are described. Optical imaging and non-imaging methods used to obtain droplet size and velocity, number density, volume flux and span information are examined, In addition to established techniques, the capabilities of two novel aerosol diagnostic instruments, the optical patternator and rainbow refractometer, are presented. The optical patternator allows for the rapid elucidation of two-dimensional spray structure, planar mass distribution and spatial droplet size distributions, Rainbow refractometry/thermometry permits the determination of droplet temperature, droplet temperature-size correlations, and droplet temperature-velocity correlations. The capabilities and limitations of each technique are summarized. Prospects for future aerosol diagnostic techniques are discussed.