Biology Chapter 3: Chromatography

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Questions and Answers

What is the purpose of Solid-Phase Extraction (SPE) in chromatography?

To analyze solid phase materials directly

To merge different liquid samples into one

To separate solid samples from liquid ones

To isolate and concentrate analytes from a liquid sample (correct)

What materials can be part of the stationary phase in SPE?

Silica, polymers, and other porous materials (correct)

Only silica particles

Solid metals with no adsorption properties

Various liquids with adsorption properties

What is the role of the stationary phase in SPE?

To dissolve the analytes completely

To speed up the flow of the liquid sample

To actively react with the analytes

To selectively retain analytes based on their interactions with the solid support (correct)

After washing away interfering substances, how are the analytes of interest retrieved in SPE?

By eluting with a solvent, then concentrating Signup and view all the answers

In which fields is SPE widely used?

Environmental analysis, pharmaceuticals, food and beverage testing, forensic toxicology Signup and view all the answers

Which type of adsorption chromatography relies on the specific interactions between sample components and ligands attached to the stationary phase?

Affinity Signup and view all the answers

What is the main principle behind ion exchange chromatography?

Separation based on charge Signup and view all the answers

Which chromatography technique separates components based on their ability to distribute themselves between the stationary and mobile phases?

Partitioning Signup and view all the answers

In which type of chromatography do larger molecules elute more quickly?

Size Exclusion Signup and view all the answers

How is elution achieved in ion exchange chromatography?

By changing ionic strength or pH of the mobile phase Signup and view all the answers

Which chromatography technique involves sample components adhering to the surface of the stationary phase?

Adsorption Signup and view all the answers

What kind of interactions are utilized in affinity chromatography for separation?

Specific ligand-receptor interactions Signup and view all the answers

What property is exploited in size exclusion chromatography to separate sample components?

Molecular size Signup and view all the answers

What is the stationary phase in Thin-Layer Chromatography (TLC)?

A thin layer of adsorbent material coated on a plate Signup and view all the answers

How is the retention factor (Rf) in TLC calculated?

By dividing the distance traveled by the component by the distance traveled by the solvent front Signup and view all the answers

What is the primary purpose of Thin-Layer Chromatography (TLC)?

Quick qualitative analysis and compound identification Signup and view all the answers

What action causes the solvent to move up the plate in TLC?

Capillary action Signup and view all the answers

What is Solid-Phase Extraction (SPE) used for?

Purifying and concentrating analytes from a liquid sample Signup and view all the answers

In SPE, what material is typically used for the stationary phase?

A solid material packed inside a column Signup and view all the answers

During which step of SPE are unwanted components removed from the sample?

Washing with a solvent Signup and view all the answers

Which industries commonly use SPE?

Environmental monitoring, drug discovery, food safety, and beverage testing Signup and view all the answers

Which phase in chromatography is immobile and where separation occurs?

Stationary Phase Signup and view all the answers

Which method of chromatography involves the separation of components based on their size and shape?

Size Exclusion Signup and view all the answers

In gas chromatography, the mobile phase typically used is:

Gas Signup and view all the answers

What is the primary purpose of the detector in a chromatography system?

To detect the separated components as they elute Signup and view all the answers

Which type of chromatography relies on specific interactions between the sample components and the stationary phase?

Affinity Signup and view all the answers

What technique is characterized by the adsorption of sample components onto the stationary phase?

Adsorption Chromatography Signup and view all the answers

Which component of chromatography is the mixture of compounds to be separated?

Sample Signup and view all the answers

In which type of chromatography does the separation occur through partitioning?

Gas chromatography (GC) Signup and view all the answers

What is involved in the data analysis component of chromatography?

Interpreting the chromatogram generated by the detector Signup and view all the answers

In ion exchange chromatography, separation is affected by which of the following?

Ionic strength or pH of the mobile phase Signup and view all the answers

Study Notes

Definition and Components of Chromatography

Chromatography is a biophysical technique used for separation, identification, and purification of mixture components for qualitative and quantitative analysis.
Stationary phase: immobile material where separation occurs (solid, liquid, or gel).
Mobile phase: fluid that carries the sample through the stationary phase (liquid, gas, or supercritical fluid).
Sample: mixture of compounds to be separated.
Column or plate: physical structure where separation takes place.
Detector: instrument that detects separated components as they elute from the column or plate.
Data analysis: interpretation of the chromatogram to determine identity and quantity of separated components.

Separation Mechanism

Partitioning: separation occurs through distribution between stationary and mobile phases (gas chromatography and liquid chromatography).
Adsorption: separation occurs through adsorption of sample components onto the stationary phase material (thin-layer chromatography and solid-phase chromatography).
Ion exchange: separation occurs based on electrostatic interactions (ionic strength or pH of the mobile phase affects separation).
Size exclusion: separation occurs based on size and shape of sample components (components too large to enter pores are excluded).
Affinity: separation occurs through specific interactions between sample components and stationary phase.

Types of Chromatography

Adsorption chromatography: relies on adsorption of sample components onto the stationary phase.
Partition chromatography: relies on partitioning of sample components between stationary and mobile phases.
Ion exchange chromatography: relies on electrostatic interactions between sample components and stationary phase.
Size exclusion chromatography: relies on size and shape of sample components.
Affinity chromatography: relies on specific interactions between sample components and stationary phase.

Thin-Layer Chromatography (TLC)

Stationary phase: thin layer of adsorbent material (silica gel or alumina) coated on a glass or plastic plate.
Sample components separate based on affinity for the stationary phase.
Distance travelled by each component is measured relative to the distance travelled by the solvent (retention factor, Rf).

Solid-Phase Extraction (SPE)

Sample preparation technique used to purify and concentrate analytes from a liquid sample.
Stationary phase: solid material packed inside a column (silica, polymers, or other porous materials with adsorption properties).
Sample is loaded onto the column, washed with a solvent, and then eluted with a solvent to concentrate the desired analytes.

Applications of Chromatography

Environmental monitoring
Drug discovery
Food safety
Beverage testing
Forensic toxicology

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Description

Learn about the biophysical technique of chromatography, its components, and its applications in separating, identifying, and purifying mixture components. Discover the roles of stationary and mobile phases.