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Next: 3.3 Liquid-Liquid Extraction Up: 3. Extraction Techniques Previous: 3.1 Introduction to Extractions   Contents

3.2 Liquid-Solid Extraction

In liquid-solid extraction, a solvent (hydrophilic or hydrophobic, acidic, neutral or basic) is added to a solid. Insoluble material can be separated by gravity or vacuum filtration, and soluble material is 'extracted' into the solvent. A sequence of solvents, of varying polarity or pH, can be used to separate complex mixtures into groups. The filtered solution can be used as a solution (for example, to be injected into the GC/MS system) or the solvent can be evaporated to recover the solute(s) in powder or crystalline form.

The figures below show several simple liquid-solid extraction schemes. {insert figures}

John S. Riley, DSB Scientific Consulting