Supercritical fluid extraction (SFE) refers to a modern separation technique that utilizes supercritical fluids as solvents to extract various compounds from solid or liquid samples. A supercritical fluid is a substance that is above its critical temperature and pressure, where it exhibits properties between those of a gas and a liquid. In this state, the fluid possesses high density and low viscosity, allowing it to readily penetrate and dissolve substances.
In supercritical fluid extraction, a sample is placed in a high-pressure chamber and the supercritical fluid, commonly carbon dioxide (CO2), is introduced. The fluid is then heated or pressurized to reach its supercritical state, causing it to become a powerful solvent. It is able to selectively dissolve targeted compounds from the sample, leaving behind undesired components. This technique is particularly useful for extracting delicate or temperature-sensitive compounds, as the low temperatures involved prevent degradation.
Once the extraction is complete, the pressure is reduced, causing the supercritical fluid to return to its gaseous state. The extracted compounds are then collected for further analysis or application. SFE offers several advantages, including its low environmental impact, since CO2 is readily available, non-toxic, and can be easily recycled. It also allows for the extraction of a wide range of compounds with adjustable selectivity by varying the temperature and pressure conditions.
Supercritical fluid extraction finds application in various industries, such as pharmaceuticals, food, cosmetics, and environmental analysis. It is employed for the extraction of natural products, essential oils, flavors, fragrances, and bioactive compounds. Additionally, SFE can be used for sample preparation in analytical methods, as it provides efficient and selective extraction.
