Chemistry: Extraction

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Questions and Answers

What is the main purpose of extraction?

To mix two or more substances together

To separate individual compounds from a complex matrix (correct)

To decrease the concentration of analytes

To change the physical phase of a substance

What is the term for the transfer of a solute from a solid phase to a liquid phase?

Solid-liquid extraction (correct)

Liquid-liquid extraction

Solvent extraction

Phase separation

What is an example of solid-liquid extraction?

Extraction of fixed oil from seeds (correct)

Mixing of two liquids to form a solution

Vaporization of a liquid

Separation of two immiscible solvents

What factor affects the rate of leaching in solid-liquid extraction?

Particle size of the solid Signup and view all the answers

Why does a smaller particle size result in a higher leaching rate?

The interfacial area between the solid and extractant becomes greater Signup and view all the answers

What is the purpose of isolation in extraction?

To separate individual compounds from a complex matrix Signup and view all the answers

What is the importance of solvent nature in solid-liquid extraction?

It affects the selectivity of the solvent Signup and view all the answers

What is an example of solid-liquid extraction used in everyday life?

Extraction of color and flavor from tea leaves Signup and view all the answers

What is the purpose of agitation in solid-liquid extraction?

To increase the eddy diffusion and transfer of material Signup and view all the answers

Which of the following factors affects the rate of leaching?

Temperature, agitation, and extraction duration Signup and view all the answers

What happens to the solubility of the extractable material with an increase in temperature?

It increases Signup and view all the answers

What is the purpose of conditioning in solid phase extraction (SPE)?

To activate the adsorbent surface to promote analyte interaction Signup and view all the answers

What is solid-liquid extraction?

The extraction of natural products from solid resources Signup and view all the answers

What is the purpose of solid phase extraction (SPE)?

To isolate one or more analytes from a liquid sample Signup and view all the answers

What is the solid stationary phase also known as in SPE?

Adsorbent Signup and view all the answers

How many consecutive steps are involved in solid phase extraction (SPE)?

Four Signup and view all the answers

Study Notes

Extraction

Extraction is the transference of a solute from one phase to another phase.
It can involve different physical phases of the same substance (e.g., liquid water and water vapor) or the same physical phases of different substances (e.g., liquid water and liquid hexane).

Goals of Extraction

Concentration: transferring an analyte from the original solvent to a smaller volume of a new solvent, resulting in substantial enrichment and concentration of analytes.
Isolation: separating individual compounds from a complex matrix or isolating a solute from a reaction solvent that is difficult to remove by evaporation.

Types of Extraction

Solid-Liquid Extraction (SLE)

Also known as leaching, it involves the transfer of a solute from a solid phase to a liquid phase.
Examples of SLE include extracting color and flavor from tea leaves, fixed oil from seeds, etc.
Factors affecting the rate of leaching:
- Particle size: smaller particles increase the leaching rate due to greater interfacial area and shorter diffusing pathway.
- Solvent nature: selectivity and low viscosity are important for easy circulation.
- Temperature: increased solubility of extractable material with temperature facilitates its escape from the matrix.
- Agitation: increases eddy diffusion and material transfer from particle surface to bulk solution.
- Extraction duration: longer extraction time increases leeching rate.
- Extraction times: repeating extraction multiple times enhances extraction rate.

Solid-Liquid Extraction Process

The extraction of natural products from solid resources progresses through:
- Solvent penetration into the solid matrix.
- Solute dissolution in the solvent.
- Solute diffusion out of the solid matrix.
- Collection of extracted solutes.

Solid Phase Extraction (SPE)

Transfer of a solute from a continuously streaming liquid (mobile phase) to a fixed solid beads (stationary phase) mainly packed in a column.
One or more analytes from a liquid sample are isolated by extracting, partitioning, and/or adsorbing onto the solid stationary phase.
Solutes are separated based on their different adsorption affinities towards the adsorbent surface.

SPE Steps

Conditioning: activating the adsorbent surface to promote analyte interaction or removing impurities.
Sample loading: passing the sample solution through the column packed with adsorbent.
Washing: removing impurities and interfering compounds.
Elution: desorbing the analyte from the adsorbent surface.

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Description

Learn about the process of extraction, its goals, and principles. Extraction is the transference of a solute from one phase to another phase. It involves transferring an analyte from the original solvent to a smaller volume of a new solvent, resulting in substantial enrichment and concentration.