Correction of interfering absorptions

Instruments with a burner generally have only low background noise in the signal. 

For the selected wavelength, using the monochromator, the flame is swept alternately by light issuing, either from the hollow cathode lamp or from the deuterium lamp, which constitutes a continuous source. A rotating mirror is used. When the deuterium lamp is selected, bearing in mind that the sample is nebulized 

CHAPTER 13 - ATOMIC ABSORPTION AND FLAME EMISSION SPECTROSCOPY 

When the hollow cathode lamp is selected, the total absorption (background and absorption due to the spectral line of the element) is measured. Absorbances being additive, the difference between the two measurements will yield the absorption due to the background corrected sample, whatever the intensities of the two lamps. 

The application of the Zeeman effect in AAS requires the application of an electromagnet at the graphite furnace (or at the flame). Two assemblies exist for correcting the background absorption. 

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