What is the Difference Between Flame Emission Spectroscopy and Atomic Absorption Spectroscopy?

Flame emission spectroscopy and atomic absorption spectroscopy are both spectro-analytical procedures used to determine the presence and concentration of certain elements in a sample. However, there are key differences between the two methods:

1. Light Emission vs. Light Absorption: The main difference between flame emission spectroscopy and atomic absorption spectroscopy lies in the way light interacts with the atoms. In flame emission spectroscopy, certain wavelengths are emitted from atoms, while in atomic absorption spectroscopy, certain wavelengths are absorbed by atoms.
2. Excitation Method: In flame emission spectroscopy, the electrons in the analyte atoms are excited by the thermal energy in the flame. In atomic absorption spectroscopy, a source of pure light is needed to excite the analytes without causing excessive instrumental noise. Most instruments today use a hollow cathode lamp that is specific to each element being analyzed to emit a very narrow bandwidth of UV or visible radiation into the instrument for detection.
3. Detection Method: In flame emission spectroscopy, the intensity of the light emitted by the excited atoms is measured, while in atomic absorption spectroscopy, the difference in the radiant power of the resonance line in the presence and absence of the analyte atoms in the flame is determined.

In summary, flame emission spectroscopy focuses on the wavelengths emitted by excited atoms, while atomic absorption spectroscopy measures the wavelengths absorbed by atoms. Both methods are used to analyze the presence and concentration of specific elements in a sample, but they use different approaches to achieve this goal.

Comparative Table: Flame Emission Spectroscopy vs Atomic Absorption Spectroscopy

Here is a table comparing the differences between Flame Emission Spectroscopy and Atomic Absorption Spectroscopy:

Both Flame Emission and Atomic Absorption Spectroscopy are spectro-analytical procedures that study the interaction of light with matter, but they differ in the way they detect and quantify the elements in a sample.