Collection and separation of particles by size from laser ablated material

Inductively coupled plasma mass spectroscopy with electrothermal vaporization has been combined for the analysis of size-classified particles from laser ablated material. An Nd:YAG laser operating in the Q-switch mode with a wavelength of 355 nm (third harmonic) was used to produce particles from a brass sample. The particles were transported by argon as carrier gas into a 11-stage impactor (0.013-11.4-mum aerodynamic particle diameter) and collected on small graphite disks (7 mm in diameter) arranged in front of the jet nozzles of cascade stages. To determine the elemental composition of the particles, the graphite disks were inserted into a specially designed electrothermal vaporizer. Cu-63, Cu-65, Zn-66, Zn-68, Pb-207, and Pb-208 were chosen for measurements. Calibration was carried out with elemental standard solutions. Relative standard deviation of the analytical signals were measured in the range from 7% (Zn) to 13% (Pb). The absolute limits of detection of these metals in solution were between 1 pg (Pb) and 10 pg (Zn). (C) 2002 Published by Elsevier Science B.V.