Separation Techniques Quiz

Filtration and Its Variants

• Main purpose of filtration is to separate solids from liquids.
• Vacuum filtration uses suction to accelerate the filtration process, making it faster than gravity filtration.
• Gravity filtration relies on the force of gravity to pull the liquid through the filter, which can be slower than vacuum filtration.

Distillation

• Distillation is effective because it separates components based on differences in boiling points.
• Different boiling points are crucial to ensure effective separation during distillation.
• Ethanol has a lower boiling point than water due to weaker intermolecular forces, facilitating easier evaporation during distillation.
• The primary function of distillation is to purify liquid mixtures by separating components.

Chromatography Techniques

• Chromatography separates compounds based on differences in their affinities for the stationary and mobile phases.
• In gas chromatography, the separation of compounds is primarily influenced by their vapor pressures.
• Larger hydrocarbons typically have lower vapor pressures and are expected to be retained longer in gas chromatography.
• A flame ionization detector in gas chromatography burns organic compounds to detect electrical current.

Liquid Chromatography

• Purpose of the liquid solvent is to dissolve the sample and carry it through the chromatographic system.
• The stationary phase exists within the chromatograph, interacting with sample components and facilitating separation based on various properties.
• Property used for separation in liquid chromatography can include polarity, size, or charge.
• Wetting the filter paper with solvent minimizes the loss of sample during filtration.
• Turning on the vacuum source enhances filtration speed by creating a pressure differential.

Size Exclusion Chromatography (SEC)

• In Size Exclusion Chromatography, smaller molecules take longer paths due to their ability to enter pores in the stationary phase, thereby increasing their travel time.
• Larger molecules move more quickly through the column because they are excluded from the pores.
• SEC specifically separates biomolecules based on size.

General Chromatography Principles

• In chromatography, components are separated based on their differing interactions with the stationary and mobile phases.
• Larger molecules elute first as they do not interact strongly with the stationary phase and can flow through the columns more freely.
• Smaller molecules are retained longer due to their interactions with the stationary phase or being trapped in small pores.

Additional Details

• When a salt and sand mixture is combined with water, the salt dissolves while the sand remains undissolved, illustrating the principle of solubility in chromatography.
• The purpose of the detector in chromatography is to quantify and identify the separated components as they elute from the column.