Background Fluorescence Spectra Observed in Atomic Fluorescence Spectrometry with a Continuum Source.

摘要

The background spectrum observed in atomic fluorescence spectrometry with a continuum source, consisting of source radiation scatter and molecular fluorescence of flame gas species, has been evaluated for the argon separated air/acetylene flame and an EIMAC xenon arc continuum source in both the pulsed and cw modes of operation. Molecular fluorescence bands were measured and assigned to PO, NH, CN, and OH. Peaks resulting from the grating second order PO fluorescence bands were observed. The spectral distribution of the source radiation was measured in both the pulsed and cw modes. Background fluorescence spectra were recorded for fuel-lean, stoichiometric, and fuel-rich conditions and spectra obtained in both the pulsed and cw modes are compared. A commercially-available filter designed to remove PH3 from acetylene was evaluated with respect to its ability to reduce the fluorescence intensity of PO, a species formed in the flame from PH3, present in the acetylene as an impurity. A general assessment of molecular fluorescence in flames as a source of interference in atomic fluorescence spectrometry is presented. (Author)