BACE Chromatography Techniques 1 — Questions and Answers
Question 1: What is the stationary phase in column chromatography?
- The mobile solvent flowing through the column
- The solid matrix packed inside the column (Correct answer)
- The sample loaded onto the column
- The eluate collected at the bottom
Correct answer: The solid matrix packed inside the column
The stationary phase is the solid matrix (e.g., resin or beads) packed inside the column that interacts with sample components to achieve separation.
Question 2: In size exclusion chromatography (SEC), which molecules elute first?
- Small molecules that enter the pores
- Molecules of intermediate size
- Large molecules that are excluded from the pores (Correct answer)
- Charged molecules regardless of size
Correct answer: Large molecules that are excluded from the pores
Large molecules are excluded from the pores of the resin and travel around them, eluting first with the void volume.
Question 3: What does the term 'elution' refer to in chromatography?
- Loading the sample onto the column
- Washing away unwanted contaminants
- Releasing and collecting separated components from the column (Correct answer)
- Equilibrating the column with buffer
Correct answer: Releasing and collecting separated components from the column
Elution is the process of washing separated analytes off the stationary phase so they can be collected as fractions.
Question 4: Which type of chromatography separates proteins based on their affinity for a specific ligand?
- Ion exchange chromatography
- Affinity chromatography (Correct answer)
- Hydrophobic interaction chromatography
- Gel filtration chromatography
Correct answer: Affinity chromatography
Affinity chromatography uses a ligand bound to the stationary phase that specifically binds the target molecule, allowing highly selective purification.
Question 5: What is the mobile phase in high-performance liquid chromatography (HPLC)?
- The column packing material
- The detector used to monitor separation
- The liquid solvent pumped through the column (Correct answer)
- The sample injection loop
Correct answer: The liquid solvent pumped through the column
In HPLC, the mobile phase is the liquid solvent mixture that carries the sample through the stationary phase under high pressure.
Question 6: In ion exchange chromatography, a cation exchange resin carries which charge?
- Positive charge to attract anions
- Negative charge to attract cations (Correct answer)
- No charge; it separates by size
- Variable charge depending on pH
Correct answer: Negative charge to attract cations
A cation exchange resin has negatively charged functional groups that attract and retain positively charged cations from the sample.
Question 7: What is the purpose of equilibrating a chromatography column before loading a sample?
- To elute any previously bound proteins
- To pack the resin more tightly
- To set the column's pH and ionic conditions to match the sample (Correct answer)
- To sterilize the column before use
Correct answer: To set the column's pH and ionic conditions to match the sample
Equilibration establishes the correct pH and ionic strength conditions in the column so that the target molecule will bind efficiently when the sample is loaded.
BACE Chromatography Techniques 1
What is the stationary phase in column chromatography?