The key difference between flame atomization and electrothermal atomization is that flame atomization has a low sensitivity than electrochemical atomization method.
Sample atomization is an important initiating step in atomic absorption spectroscopy. It requires the conversion of a sample into its gaseous atoms that can absorb the radiation. Most commonly, we use the sample as a solution in atomic absorption spectroscopy. In this technique, the solution is passed into a small tube which can be taken to the nebulizer. In the nebulizer, the solution breaks up into a fine mist. This fine mist is then passed to the atomizer, breaking the sample into its individual atoms, which is known as atomization.
CONTENTS
1. Overview and Key Difference
2. What is Flame Atomization
3. What is Electrothermal Atomization
4. Flame Atomization vs Electrothermal Atomization in Tabular Form
5. Summary – Flame Atomization vs Electrothermal Atomization
What is Flame Atomization?
Flame atomization is an analytical technique used in atomic absorption spectroscopy, which involves the mixing of a nebulized gaseous oxidant with fuel which is then passed into a flame where the heat is allowing the sample to undergo atomization. In this technique, when the sample reaches the flame, desolvation, volatilization, and dissociation occur. Initially, a molecular aerosol is formed when the solvent evaporates. This step is called the desolvation step. The second step involves the formation of aerosol into gaseous molecules. This is the volatilization step. The final step is the dissociation and production of the atomic gas, known as the dissociation step. Moreover, cations and electrons can also form upon the ionization of atomic gas.
In the flame atomization process, we can use a mixture of different oxidants and fuels, which are useful in achieving a specific temperature range. This is because the dissociation and breakdown of molecules into atoms are easier with the presence of heat. Here, oxygen gas is the most common oxidant. We can use a rotameter to monitor the flow rate of an oxidant and fuel. Further, the rotameter is a vertically tapered tube, having the smallest end placed down, and a float is located inside the tube.
What is Electrothermal Atomization?
Electrochemical atomization or electrothermal atomization is a technique where a sample is passed through three phases in order to achieve atomization. In the first phase, the sample dries out at a low temperature. The second phase involves the ashing of the sample in a graphite furnace. The third phase is the rapid temperature increase inside the furnace to make the vapour phase of the sample; the vapour phase contains the atoms from the sample. We can measure the absorption using these atoms by placing the sample above the heated surface.
Typically, the graphite furnace contains a graphite tube that is open at both ends. It has a hole in the middle, which can be used to introduce the sample. Moreover, this tube is encased within graphite electrical contacts at both ends. These electrical contacts serve to heat the sample. However, we need to use a supply of water to keep the graphite furnace cool. In addition, we need an external stream of inert gas which flows around the tube to avoid the entering of outside air and destroy the tube.
What is the Difference Between Flame Atomization and Electrothermal Atomization?
Flame atomization is an analytical technique useful in atomic absorption spectroscopy which involves the mixing of the nebulized gaseous oxidant with fuel which is then passed into a flame where the heat is allowing the sample to undergo atomization. Electrochemical atomization, on the other hand, is a technique where a sample is passed through three phases in order to achieve atomization. The key difference between flame atomization and electrothermal atomization is that flame atomization has a low sensitivity than the electrochemical atomization method.
The below infographic lists the differences between flame atomization and electrothermal atomization in tabular form for side by side comparison
Summary – Flame Atomization vs Electrothermal Atomization
Sample atomization is an important initiating step in atomic absorption spectroscopy. It requires the conversion of a sample into its gaseous atoms that can absorb the radiation. The key difference between flame atomization and electrothermal atomization is that flame atomization has a low sensitivity than the electrochemical atomization method.
Reference:
1. “Sample Atomization | Atomic Absorption Spectroscopy Learning Module“, MaryVille Education.
Image Courtesy:
1. “Atomization” By Figure 9. a) Atomization system for powder production and b) Copper powder prepared – Research Gate (CC BY-SA 4.0) via Commons Wikimedia