Molekülabsorptionsspektrometrie bei elektrothermischer verdampfung in einer graphitrohrküvette: II. Bestimmung von fluoridspuren in mikrovolumina durch die molekülabsorption von GaF-molekülen

Abstract

Molecular absorption spectrometry by electrothermal volatilization in a graphite furnace. Part 2. The determination of traces of fluoride by GaF molecular absorption A direct determination of traces of fluoride by measurement of the GaF molecular absorption in a graphite furnace is described. The optimal conditions, for compensation of the non-specific absorption and for temperatures of ashing and volatilization, are discussed. The effects of the Ga 3+ and Na + concentrations and of several acids on the determination are reported. Increasing concentrations of Ga 3+ ions increase the concentration of GaF molecules in the graphite furnace plasma. Higher Na +-concentrations decrease the loss of HF in the drying time. The detection limit (3 s) is 1.6 ng F -/10 μl; the sensitivity is 0.8 ng F -/10 μl for 0.01 absorbance units. The influence of Cl --, Br --, J --, SO 4 2--, BO 3 3--, SiO 3 2--, Li +-, K +-, Be 2+-, Mg 2+-, Ca 2+-, Al 3+-, In 3+-, Zn 2+-, Cd 2+- and Fe 3+- ions on the determination are described.