Partition column chromatography – principles and applications MCQs With Answer

Introduction
Partition column chromatography is a liquid–liquid separation technique that separates solutes based on their differing partition coefficients between a liquid stationary phase and a liquid mobile phase. Common formats include paper, column partition, and countercurrent chromatography used in pharmaceutical analysis. Key concepts for B.Pharm students include partition coefficient (K), distribution ratio, stationary/mobile phase selection, solvent systems, separation factor, retention factor, theoretical plates, and method optimization. This method minimizes irreversible adsorption and is valuable for extracting natural products, purifying drug intermediates, and preparative separations. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is the primary principle of partition column chromatography?

• Separation based on ionic exchange with a solid resin
• Separation based on differential adsorption to silica gel
• Separation based on differential partitioning between two immiscible liquid phases
• Separation based on molecular size through pores

Correct Answer: Separation based on differential partitioning between two immiscible liquid phases

Q2. How is the partition coefficient (K) defined in partition chromatography?

• Ratio of solute concentration in mobile phase to stationary phase
• Ratio of solute concentration in stationary phase to mobile phase
• Difference between concentrations in two phases
• Product of concentrations in both phases

Correct Answer: Ratio of solute concentration in stationary phase to mobile phase

Q3. Which of the following is a typical stationary phase in classical partition column chromatography?

• Silica gel powder
• Paper or immiscible liquid held on a support
• Neutral alumina
• Ion exchange resin

Correct Answer: Paper or immiscible liquid held on a support

Q4. Which technique is a liquid–liquid partition method commonly used for preparative separations in pharmaceutical chemistry?

• Thin layer chromatography (TLC)
• Countercurrent chromatography (CCC)
• Gas chromatography (GC)
• Size exclusion chromatography (SEC)

Correct Answer: Countercurrent chromatography (CCC)

Q5. In partition chromatography, increasing the partition coefficient (K) of a solute generally causes which effect on retention?

• Shorter retention time
• No change in retention
• Longer retention time
• Immediate elution with dead volume

Correct Answer: Longer retention time

Q6. What does the separation factor (α) represent?

• Ratio of partition coefficients of two solutes
• Difference in molecular weights of two solutes
• Sum of retention times of two solutes
• Flow rate divided by column length

Correct Answer: Ratio of partition coefficients of two solutes

Q7. Which parameter is defined by k’ = (tR – t0)/t0 in chromatographic theory?

• Partition coefficient (K)
• Retention factor (k’)
• Separation factor (α)
• Theoretical plate number (N)

Correct Answer: Retention factor (k’)

Q8. Why is solvent system selection critical in partition chromatography?

• It determines detector wavelength
• It controls the partitioning behavior and selectivity between phases
• It only affects column pressure but not separation
• It is only important for solid-phase methods

Correct Answer: It controls the partitioning behavior and selectivity between phases

Q9. Which advantage is specifically associated with liquid–liquid partition column chromatography compared to adsorption chromatography?

• Higher irreversible adsorption of analytes
• Better separation for ionic species only
• Reduced irreversible adsorption and gentle handling of labile compounds
• Lower solvent consumption always

Correct Answer: Reduced irreversible adsorption and gentle handling of labile compounds

Q10. Countercurrent chromatography achieves separation by:

• Using a solid stationary phase with covalently bound ligands
• Partitioning solutes between two immiscible liquid phases while one is retained by centrifugal force
• Gas–liquid partitioning under high temperature
• Size exclusion in packed beads

Correct Answer: Partitioning solutes between two immiscible liquid phases while one is retained by centrifugal force

Q11. Theoretical plates (N) are a measure of:

• Column mechanical strength
• Chromatographic efficiency and band spreading
• Solvent purity
• Detector sensitivity

Correct Answer: Chromatographic efficiency and band spreading

Q12. Which factor will most likely increase resolution between two nearby peaks in partition chromatography?

• Increasing flow rate drastically
• Decreasing column length
• Optimizing solvent composition to change selectivity
• Using a detector with lower sensitivity

Correct Answer: Optimizing solvent composition to change selectivity

Q13. In a two-phase solvent system, if a solute has K = 1, what does that indicate?

• Solute is only in the mobile phase
• Solute is only in the stationary phase
• Equal distribution between stationary and mobile phases
• Solute is immiscible and precipitates

Correct Answer: Equal distribution between stationary and mobile phases

Q14. Which detection method is commonly used for partition chromatography of pharmaceutical compounds?

• Flame ionization detector (FID) only
• UV-Vis absorbance and refractive index detectors
• Thermal conductivity detector only
• Geiger counter

Correct Answer: UV-Vis absorbance and refractive index detectors

Q15. How does temperature generally affect partition coefficients for most solutes?

• Temperature has no effect on K
• Higher temperature can change K by affecting solubility and partitioning
• Lower temperature always increases K
• It converts partition chromatography into adsorption chromatography

Correct Answer: Higher temperature can change K by affecting solubility and partitioning

Q16. Which of the following is a disadvantage of partition column chromatography?

• High risk of irreversible adsorption
• Poor scalability to preparative scales
• Formation of emulsions and phase instability with some solvent systems
• Complete incompatibility with natural product separations

Correct Answer: Formation of emulsions and phase instability with some solvent systems

Q17. In countercurrent chromatography, what role does centrifugal force play?

• It heats the column to vaporize the solvent
• It retains the stationary liquid phase while mobile phase flows through
• It mixes solid packing material evenly
• It replaces the need for detectors

Correct Answer: It retains the stationary liquid phase while mobile phase flows through

Q18. Distribution ratio (D) differs from partition coefficient (K) because D:

• Is measured only at infinite dilution
• Accounts for all species including ionized and non-ionized forms in both phases
• Is always equal to K
• Is irrelevant in liquid–liquid systems

Correct Answer: Accounts for all species including ionized and non-ionized forms in both phases

Q19. For ionizable drug molecules, which parameter critically affects partitioning between phases?

• Detector wavelength
• Solution pH and pKa of the drug
• Column mechanical strength
• Ambient humidity only

Correct Answer: Solution pH and pKa of the drug

Q20. Which of the following strategies will reduce band broadening in partition column chromatography?

• Using a longer and narrower column while optimizing flow rate
• Increasing injection volume without changing conditions
• Choosing a solvent system that causes strong emulsion formation
• Operating detector at lower sensitivity

Correct Answer: Using a longer and narrower column while optimizing flow rate

Q21. Paper chromatography is best described as which type of partition method?

• Liquid–solid adsorption chromatography
• Liquid–liquid partition chromatography with water trapped in paper fibers
• Gas–solid chromatography
• Size exclusion chromatography

Correct Answer: Liquid–liquid partition chromatography with water trapped in paper fibers

Q22. When scaling up partition chromatography for preparative work, which consideration is most important?

• Ignoring solvent costs
• Maintaining similar phase ratio and solvent composition to retain selectivity
• Reducing column length drastically
• Using any detector without validation

Correct Answer: Maintaining similar phase ratio and solvent composition to retain selectivity

Q23. Which van Deemter term corresponds to longitudinal diffusion affecting plate height in liquid chromatography?

• A term (eddy diffusion)
• B term (longitudinal diffusion)
• C term (mass transfer)
• D term (column diameter)

Correct Answer: B term (longitudinal diffusion)

Q24. Which mobile phase modification can increase the retention of a polar solute in a normal-phase partition system?

• Increase polarity of mobile phase substantially
• Decrease polarity of mobile phase
• Use pure water as mobile phase only
• Reduce column length to zero

Correct Answer: Decrease polarity of mobile phase

Q25. A high separation factor (α) between two compounds indicates:

• Poor selectivity and overlapping peaks
• Good selectivity and easier baseline separation
• Identical partitioning behavior
• That both compounds are volatile gases

Correct Answer: Good selectivity and easier baseline separation

Q26. Which application is partition column chromatography frequently used for in pharmaceutical analysis?

• Determination of elemental impurities by ICP-MS only
• Purification of natural product extracts and drug intermediates
• Direct solid-state characterization of APIs
• Measuring tablet hardness

Correct Answer: Purification of natural product extracts and drug intermediates

Q27. If two solutes have identical partition coefficients but different diffusion rates, what effect is expected?

• They will co-elute exactly regardless of column conditions
• One may show broader peak due to mass transfer differences, reducing resolution
• Both will be unaffected by diffusion
• The slower-diffusing solute will disappear

Correct Answer: One may show broader peak due to mass transfer differences, reducing resolution

Q28. In immobilized liquid chromatography (a variant of partition chromatography), what is immobilized?

• Mobile phase solvent is permanently evaporated
• Liquid stationary phase is chemically bonded to a solid support
• Detector is fixed to the column
• Sample is immobilized on the detector

Correct Answer: Liquid stationary phase is chemically bonded to a solid support

Q29. Which practice helps avoid emulsion formation in liquid–liquid partition separations?

• Vigorous prolonged shaking of phases
• Selecting mutually immiscible solvents with suitable density difference and gentle mixing
• Using surfactants indiscriminately
• Running at very high temperatures to boil solvents

Correct Answer: Selecting mutually immiscible solvents with suitable density difference and gentle mixing

Q30. For separating two acidic drug impurities, which mobile-phase adjustment is most useful?

• Adjust pH to suppress ionization of acids to favor partitioning into organic phase
• Adjust pH to fully ionize acids to increase partitioning into organic phase
• Always use purely neutral solvent regardless of pKa
• Add solid salts to precipitate analytes

Correct Answer: Adjust pH to suppress ionization of acids to favor partitioning into organic phase

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com