Dissociation and ionization effects in atomic absorption spectrochemical analysis

Abstract

Use of a nitrous oxide-acetylene flame in atomic absorption spectrophotometry reduces or eliminates certain chemical interferences that have been observed in cooler flames. However, ionization increases with temperature, and is significant for some elements in the nitrous oxide-acetylene flame. Ionization can be reduced by adding an easily ionized metal (e.g. alkali metal) to the solution. Elements likely to be determined using the nitrous oxide-acetylene flame which will be significantly ionized are: Al, Ba, Ti, V, Zr, Hf, Nb, Sc, Y, the lanthanides and the actinides. The ionization of an element in the nitrous oxide-acetylene flame can be readily calculated by taking absorption readings, provided that relatively sensitive atom and ion resonance lines are available. This technique possibly could be used to establish ionization potentials or partition functions of those lanthanide elements that are not now well known.