Impact of source and free atom density spatial non-uniformities in electrothermal atomic absorption spectrometry

Abstract

Using various atom density gradients within the furnace combined with several spatial distributions of the lamp image profile, the impact on the measured analytical signal (using peak areas) has been modeled. Atom density gradients which decrease from bottom to top of the furnace together with distributions which increase either toward the center of the furnace or toward the wall are considered. The calculation of the absorbance signal is done using two approaches. Case I involves use of the integrated intensity after passing through the absorbers in the furnace and ratioing this value to the integrated intensity in the absence of absorbers to finally calculate the absorbance. In Case II the final absorbance is calculated using the average absorbance through each spatial zone. Non-linearities in the calibration curve and changes in sensitivity are minimized using Case II in most situations.