18 Questions
In adsorption chromatography, which component is the polar absorbent?
CH3OH Methanol
What does the retention factor (Rf) in chromatography represent?
Distribution coefficient for a compound
For paper chromatography, which method is used for visualizing components non-destructively?
Iodine vapour forming a coloured complex
Which solvent is commonly used in liquid chromatography?
Methanol
What visualization method is typically employed in carrying out paper chromatography for amino acids?
Spot visualization using Ultra violet lamp
Which compound chemically bonds to the polar absorbent in adsorption chromatography?
Caprylic acid
What greatly influences the column efficiency in chromatography?
Length of the column
Which mode of separation is popularly used in HPLC?
Partition
What is the mobile phase in gas chromatography?
Gas
Which chromatographic technique is considered the gold standard for analyzing volatile organic compounds (VOCs)?
Liquid chromatography
What reagent can be used to detect alkaloids in partition chromatography?
Dragendorff’s reagent
In which type of chromatography are components of a chemical mixture partitioned between a moving gas and a stationary liquid phase?
Gas chromatography
What is the main principle behind adsorption chromatography?
Adsorption of the mobile phase onto the surface of a stationary solid phase
In partition chromatography, what does the separation primarily depend on?
Differences in solubility of sample components in the stationary phase
Why is paper chromatography considered an example of partition chromatography?
Dependent on differences in the partition coefficients of the components between water and an immiscible organic liquid
What role does liquid chromatography play in paper chromatography?
It helps in forming a thin film on the surface of the solid support
What aspects should be considered when carrying out paper chromatography?
Apparatus used, preparation of the sample, development of the chromatogram
Which type of chromatography involves equilibration between the mobile phase and a stationary liquid?
Partition Chromatography
Study Notes
Adsorption Chromatography
- Acyl carbon chains of varying length are chemically bonded to the polar absorbent in adsorption chromatography
- The mobile phase consists of solvents such as methanol, butanol, and n-hexane
- Caprylic acid is one of the solutes used in adsorption chromatography
- Quercetin is another solute used in adsorption chromatography
- The retention factor (Rf) is the ratio of the distance traveled by the solute to the distance traveled by the solvent
- Rf value is specific and constant for a particular compound and reflects the distribution coefficient for that compound under standard conditions
Paper Chromatography
- Paper chromatography is a technique used in adsorption chromatography
- It involves spotting a sample on a stationary phase and allowing it to develop
- The distance traveled by the solute is compared to the distance traveled by the solvent to calculate the Rf value
- Visualization techniques are used to detect separated components, including iodine vapor and UV lamps
- Some components may not be visible and require derivatization or other visualization methods
Partition Chromatography
- Partition chromatography separates solutes based on differences in solubility between the mobile and stationary phases
- It is a type of liquid chromatography (LC)
- Paper chromatography is an example of partition chromatography
- The separation of a mixture is dependent on differences in partition coefficients of the components between an aqueous and immiscible organic liquid
- Partition chromatography involves a thin film formed on the surface of a solid support by a liquid stationary phase
- Solute equilibrates between the mobile phase and the stationary liquid
Gas Chromatography
- Gas chromatography is a type of partition chromatography
- The mobile phase is a gas (carrier gas)
- Partitioning components of a chemical mixture occur between the moving gas and stationary liquid phase
- Gas chromatography is recognized as one of the most powerful separative methods available
- It can detect very low amounts of compounds (parts per billion) and is the gold standard for volatile organic components (VOCs) analyses
Learn about adsorption chromatography and how to calculate the retention factor (Rf) in chromatography experiments. Understand the relationship between the distance traveled by the solute and the solvent.
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