Spectral interferences and stray light in continuum source excited flame atomic-fluorescence spectrometry

Abstract

Sectral interferences were shown to be caused primarily by fluorescence of the interfering species within the spectral band pass of the monochromator. When the spectral band pass of the monochromator was limited to 0.1 nm there were no significant spectral interferences.

The choice of a single or double monochromator for discrimination against stray light depends on different considerations when a line source is used compared with a continuum source. Improvements in the signal to noise ratio when using a double monochromator were less when a continuum source was in use.

Use of the short-arc xenon arc for the excitation of elements that have analytical lines below 214 nm was possible and gave parts per million level detection limits, but only during the first 14 h of lamp life. Radio-frequency-excited electrodeless discharge lamps gave similar or better detection limits in the UV region. A hybrid multi-element instrument with both types of light source is therefore better for the determination of the greatest number of elements.