The key difference between supercritical fluid extraction and microwave assisted extraction is that in supercritical fluid extraction method, the extraction is done using a supercritical fluid as the extracting solvent, whereas in microwave assisted extraction, extraction is done using microwave energy.
Supercritical fluid extraction and microwave assisted extraction are two types of important analytical techniques. Supercritical fluid extraction or SFE is a highly selective method in which we use pressurized fluid as solvents. Microwave-assisted extraction or MAE is a conventional technique used for the extraction of active components from medicinal plants using microwave energy.
CONTENTS
1. Overview and Key Difference
2. What is Supercritical Fluid Extraction
3. What is Microwave Assisted Extraction
4. Supercritical Fluid Extraction vs Microwave Assisted Extraction in Tabular Form
5. Summary – Supercritical Fluid Extraction vs Microwave Assisted Extraction
What is Supercritical Fluid Extraction?
Supercritical fluid extraction or SFE is a highly selective method in which we use pressurized fluid as solvents. It is an analytical process that separates one component from another using supercritical fluid as the extracting solvent. The former component is called the extractant, and the latter is called the matrix.
Generally, this extraction is done from a solid matrix, but it can also be done from liquids. Moreover, we can use this method as a sample preparation step for analytical applications. We can also use it in large-scale applications to either strip the unwanted material from a product or to collect the desired product. A good example of the stripping of unwanted materials is decaffeination. An example of collecting the desired product is essential oils.
The most used supercritical fluid is carbon dioxide. Sometimes it is modified before use. The modifications are done using ethanol or methanol. The extraction conditions that we need to use for supercritical carbon dioxide are a temperature above the critical temperature (31 degrees Celsius) and critical pressure (74 bar). However, the addition of the modifiers can alter these conditions.
What is Microwave Assisted Extraction?
Microwave assisted extraction or MAE is a conventional technique used for the extraction of active components from medicinal plants using microwave energy. Here, microwave energy is used to heat solvents that consist of the samples. Therefore, the analytes partition from a sample matrix into the solvent.
It is an efficient method involving deriving natural compounds from raw plants. This method also allows organic compounds to be extracted more rapidly compared to conventional extraction methods.
There are several important advantages of this method over the soxhlet method.
- Reduction in extraction time
- Improved yield
- Better accuracy
- Suitability for thermolabile substance
When considering the extraction principle, the target for microwave heating is the minute microscopic trace of moisture in the dried plants. Usually, the inside of the oven has a high temperature and pressure. This high temperature can cause the dehydration of the cellulose and this, in turn, reduces the mechanical strength. The major steps of the MAE method are as follows.
- Microwave radiation
- Moisture getting heated-up
- Moisture evaporation
- Formation of tremendous pressure on cell wall
- This causes the swelling of plant cell
- Rupturing of the cell
- Removal of phyto-constituents
What is the Difference Between Supercritical Fluid Extraction and Microwave Assisted Extraction?
Supercritical fluid extraction (SFE) is a highly selective method where fluids are pressurized as solvents while microwave assisted extraction (MAE) is a conventional technique for the extraction of active components from medicinal plants using microwave energy. The key difference between supercritical fluid extraction and microwave-assisted extraction is that supercritical fluid extraction method uses a supercritical fluid as the extracting solvent, whereas microwave assisted extraction uses microwave energy for the extraction.
The below infographic presents the differences between supercritical fluid extraction and microwave-assisted extraction in tabular form for side-by-side comparison.
Summary – Supercritical Fluid Extraction vs Microwave Assisted Extraction
Extraction is an analytical technique to separate the desired component from a mixture of components. Supercritical fluid extraction and microwave assisted extraction are two types of important analytical techniques. The key difference between supercritical fluid extraction and microwave-assisted extraction is that supercritical fluid extraction method uses a supercritical fluid as the extracting solvent, whereas microwave assisted extraction uses microwave energy for the extraction.
Reference:
1. “Supercritical Fluid Extraction.” An Overview | ScienceDirect Topics.
Image Courtesy:
1. “Thar Process SFC system” By Tharprocess1 – Own work (CC BY-SA 4.0) via Commons Wikimedia