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Unformatted text preview: readily atomized, resulting in a
lower concentration of iron atoms in the flame. b) Lessen sulfate interference by:
• adding a releasing agent that forms complexes with sulfate that are
more stable than the iron-sulfate complexes; • adding a protective agent, such as EDTA, that forms a highly stable
but volatile complex with Fe(III); • using a higher temperature flame (oxygen/acetylene or nitrous
oxide/acetylene). 17. During drying and ashing, volatile absorbing species may have been formed. In addition,
particulate matter would appear as smoke during the ashing and would scatter the source
radiation. 19. When an internal standard is used, the ratio of the intensity of the analyte line to that of the
internal standard is plotted as a function of the concentration of the analyte. This intensity
ratio for the unknown can be used with the calibration curve to assess the unknown
concentration. If the internal standard and the analyte species are influenced in the same
way by variations in the aspiration rate and temperature of the source, and if the internal
standard is present at the same concentration in the calibration standards and unknown,
the result is independent of these variables....
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This document was uploaded on 03/06/2014 for the course CHEM 422 at CSU Northridge.
- Fall '08