High speed photographic study of plasma fluctuations and intact aerosol particles or droplets in inductively coupled plasma mass spectrometry
Cine-films of the inductively coupled plasma were taken at 3000 frames s–1 while the plasma was sampled for mass spectrometry. The axial channel expanded and contracted periodically at frequencies of 260–300 Hz, depending on the operating conditions. The frequency of the observed fluctuations decreased as the separation between the torch and sampling cone increased. With a concentric nebulizer, emission from vapour clouds surrounding the aerosol droplets or particles was observed flowing along the axial channel and into the sampling orifice.