Inductively coupled plasmas in analytical atomic spectrometry: Excitation mechanisms and analytical feasibilities

Abstract

The excitation mechanisms in an inductively coupled plasma are discussed based on a collisional-radiative process theory. In the theory, the kinetic processes such as electron impact excitation and de-excitation, electron impact ionization and three-body recombination, spontaneous emission and induced absorption, radiative recombination, Penning ionization, and charge transfer are taken into consideration to interpret the excitation mechanisms in the argon ICP. These considerations suggest that the electron-collisional excitation/de-excitation and ionization processes are dominant in determining the atom and ion populations in the normal analytical zone, although the non-LTE properties of the plasma are caused mainly by the radiative processes. In addition, the graphite cup direct insertion technique will be discussed as a new analytical method for solution and solid sample analysis. © 1988 IUPAC