A.A.S. is that branch of Analytical Chemistry with the help of which we can have quantitative analysis by knowing the amount of light absorbed by the atoms which are present in the ground state in the unexcited form. The points of superiority of A.A.S. to flame photometry are as follow:
1. If the analyst has to analyze several samples in a day it is possible with A.A.S. and is not possible with flame photometry, because A.A.S. requires less time than flame photometry.
2. The A.A.S. technique is specific as source of radiations is specific (special) Therefore; spectral interference of the lines is not taking place.
3. As the absorption of radiations is by the atoms present in the ground state, so the temperature change do not affect the absorption but in flame photometry, the temperature of the flame is very important.
4. A.A.S. is sensitive to more number of the elements. About 70 different elements can be analyzed by A.A.S. while flame photometry seems limited scope.
5. So many elements like Zn cannot be excited. For such elements the analysis by flame Photometry is not possible but A.A.S. analysis is possible. Because there is no excitation and A.A.S. depends on the absorption.
6. As the A.A.S. obeys the Beer - Lambert’s Law hence the absorbance varies in linear manner with concentration under a wide range of concentration. This is not in the case of flame photometry.
On the whole A.A.S. will always give better results, is less time consuming and have more scope. That is why the A.A.S. is superior technique to flame photometry.
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