Effects of Solution Physical Properties on Copper and Chromium Signals in Flame Atomic Absorption Spectrometry

• Fàbio R. P. Rocha ^[1] ; Joaquim A. Nòbrega ^[1]
  1. [1] Universidade Federal de São Carlos

     Universidade Federal de São Carlos

     Brasil

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 73, Nº 10 (October), 1996, págs. 982-984
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Instrumental techniques, such as flame atomic absorption spectrometry (FAAS), are frequently used in chemical analysis. Independently of the technique used, the chemical principles must be considered to assure that the analytical results are correct. In FAAS, the most critical step is the sample introduction, since solutions need to be converted in an aerosol (nebulization process) that should contain drops with suitable size to attain the flame. Solution physical properties, such as viscosity and surface tension, can severely affect the analytical signals. Solutions with high viscosity are less easily aspirated and the analyte mass that reach the flame is reduced. The surface tension of the solution affects the size of the drops generated by the nebulization process and can modify the quantity of analyte that attain the flame. This work describes an experiment that allow demonstrating the effects of viscosity and surface tension on analytical signals, using a set of copper solutions prepared in different concentrations of ethanol and chromium solutions prepared in surfactant (tetrapropylammonium bromide) medium. The experiment can be carried out in a 4 h laboratory class and is useful to demonstrate to undergraduate students the effects of samples physical properties on the analytical signals in FAAS.