STUDIES OF EVAPORATION AND PLASMA PROCESSES IN GRAPHITE CUVETTES FOR OPTIMIZATION OF AAS ANALYSIS .2. MOLECULAR ABSORPTION SPECTROMETRY AND ATOMIC-ABSORPTION SPECTROMETRY OF AQUEOUS-SOLUTIONS AND ORGANIC EXTRACTS OF GALLIUM AND INDIUM

The authors compared the sensitivities achieved in the determination of Ga and In by AAS with electrothermal atomization in graphite cuvettes in dependence on the solvent, i.e. some acids and organic extracts. The best sensitivity was found in an HNO3 environment. Signal depressions were observed especially in the presence of halides and with solvents containing halogens. The results of the investigations showed that the principal cause of the depressions is the formation of stable molecules of the type MX (M = Ga or In; X = Cl or Br) in the gaseous state. A second cause is the evaporation. The temperature, in particular that prevailing during the ashing step affects the X-concentration in the gaseous state because of thermal hydrolysis of unstable salts or evaporation of the organic solvents. © 1979.