Simultaneous elemental composition and size distributions of submicron particles in real time using laser atomization/ionization mass spectrometry

Abstract

Composition and size of individual submicron particles have been measured using a laser atomization/ionization mass spectrometry technique, the Particle Blaster. Individual particles are quantitatively converted to atomic cations, providing information on both their complete elemental composition and particle size. Measured average atomic ratios for ~ 100 nm particles of sodium chloride is 1.12 ± 0.36 (C1:Na), for 50 nm particles of silica is 1.93 ± 0.52 (O:Si), and for 64 nm polystyrene latex spheres (PSL) is 1.13 ± 0.19 (H:C), in excellent agreement with the empirical formulae. Calculated particle sizes agree well with electrostatic classifier or TEM measurements in the size range of 17-900 nm diameter for particles of sodium chloride, silicon, and PSL. Size distributions are also obtainable, giving narrower distributions than are measured with an electrostatic classifier, for particles of alumina, silica, sodium chloride, and PSL spheres. Comparison with TEM data shows comparable primary particle sizes, but numerous particle aggregates are detected by the Particle Blaster which are unreported by the TEM measurements.