How does solid-supported liquid-liquid extraction differ from solid-phase extraction?

• The extraction technique can be used to purify compounds or separate compound mixtures, such as isolating a product from a reaction mixture (known as an extractive work-up). It can also be used to isolate natural products, such as caffeine from tea leaves.
• Solid-Phase Extraction (SPE) is a sample preparation method that is used in a variety of fields due to its numerous advantages over other traditional methods. SPE was developed as an alternative to liquid/liquid extraction because it eliminated several disadvantages, including the use of a large amount of solvent, extended operation time/procedure steps, potential sources of error, and high cost.

(1) Solid-supported liquid-liquid extraction:

• Aqueous phase remains suspended in a microporous medium where organic solvent is passed through in order to extract analytes
• Liquid extraction, also known as partitioning, is a separation process that involves the transfer of a solute from one solvent to another, with the two solvents being immiscible or partially miscible.

(2) Solid-phase extraction:

• Aqueous sample passes through small column of the stationary phase which retains analytes
• Analytes and impurities are eluted by washing it many times with small volumes of solvent with an increase in the solvent strength
• Furthermore, SPE can be applied to samples in conjunction with other analytical methods and sample preparation techniques.
• Because of its versatility, the SPE technique is a useful tool for a variety of purposes. The main approaches in this method's practises are isolation, concentration, purification, and cleanup.