Chromatographic techniques in standardization of herbal products MCQs With Answer

Chromatographic techniques are essential tools in the standardization and quality control of herbal products. For B.Pharm students, understanding separations such as thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), gas chromatography (GC) and hyphenated methods (LC-MS, GC-MS) is vital for phytochemical analysis, marker identification, purity testing and quantitative assay development. Method validation, resolution, retention time, mobile phase selection and detector choice determine reliable results. These techniques help detect adulteration, batch-to-batch variability and ensure safety and efficacy of herbal formulations. This concise review reinforces practical and theoretical aspects of chromatographic methods applicable to herbal standardization, preparing you for laboratory work and regulatory expectations. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which chromatographic parameter directly describes the relative migration of a compound on a TLC plate?

• Retention time
• Retention factor (k’)
• Resolution (Rs)
• Rf value

Correct Answer: Rf value

Q2. In reversed-phase HPLC of polar herbal constituents, which stationary phase is most commonly used?

• Sulfuric acid-treated silica
• C18 (octadecyl) bonded silica
• Porous graphitic carbon
• Alumina

Correct Answer: C18 (octadecyl) bonded silica

Q3. The van Deemter equation primarily helps to optimize which chromatographic attribute?

• Detector sensitivity
• Plate height and column efficiency
• Mobile phase pH
• Sample dilution factor

Correct Answer: Plate height and column efficiency

Q4. Which detector is most suitable for detecting non-volatile phytochemicals in HPLC with high specificity?

• Flame ionization detector (FID)
• Mass spectrometer (MS)
• Thermal conductivity detector (TCD)
• Electron capture detector (ECD)

Correct Answer: Mass spectrometer (MS)

Q5. In method validation for herbal standardization, which parameter assesses the smallest concentration that can be reliably quantified with acceptable accuracy and precision?

• Specificity
• Limit of detection (LOD)
• Limit of quantification (LOQ)
• Robustness

Correct Answer: Limit of quantification (LOQ)

Q6. Which mobile phase change is typically used to improve elution of strongly retained non-polar compounds in reversed-phase HPLC?

• Decrease organic content
• Use pure water
• Increase organic solvent percentage (e.g., acetonitrile)
• Add more buffer salt

Correct Answer: Increase organic solvent percentage (e.g., acetonitrile)

Q7. For GC analysis of herbal volatile oils, what sample preparation step is commonly required?

• Derivatization to increase volatility
• Direct injection of raw powder
• Ion exchange chromatography
• Dialysis

Correct Answer: Derivatization to increase volatility

Q8. In TLC fingerprinting of herbs, what advantage does a fingerprint profile provide for standardization?

• Quantifies trace metals
• Determines molecular weight
• Shows characteristic pattern of multiple phytochemicals for identity and consistency
• Measures moisture content

Correct Answer: Shows characteristic pattern of multiple phytochemicals for identity and consistency

Q9. Which of the following describes the capacity factor (k’) in chromatography?

• Ratio of signal to noise
• Measure of peak symmetry
• Relative retention of analyte compared to dead time
• Column backpressure

Correct Answer: Relative retention of analyte compared to dead time

Q10. In HPLC method development for herbal constituents, gradient elution is preferred over isocratic when:

• All analytes have identical polarity
• Analytes range widely in polarity and retention
• Only one analyte is present
• Column lifetime must be shortened

Correct Answer: Analytes range widely in polarity and retention

Q11. Which chromatographic term describes the separation quality between two adjacent peaks?

• Resolution (Rs)
• Elution order
• Dead time (t0)
• Plate count (N)

Correct Answer: Resolution (Rs)

Q12. Which modifier is often added to mobile phases to improve peak shape for basic herbal alkaloids in RP-HPLC?

• Triethylamine or formic acid (buffered modifier)
• Sodium chloride crystals
• Hydrogen peroxide
• Glycerol

Correct Answer: Triethylamine or formic acid (buffered modifier)

Q13. What is the primary purpose of system suitability tests before chromatographic analysis of herbal samples?

• To sterilize the column
• To verify system performance parameters like resolution, theoretical plates and tailing
• To adjust pH of the sample
• To concentrate the sample

Correct Answer: To verify system performance parameters like resolution, theoretical plates and tailing

Q14. Which parameter indicates how symmetrical a chromatographic peak is?

• Retention factor
• Tailing factor
• Dead time
• LOD

Correct Answer: Tailing factor

Q15. In HPTLC for herbal standardization, derivatization reagents are used to:

• Increase column pressure
• Enhance visualization of specific phytochemical classes
• Evaporate solvents
• Change stationary phase chemistry

Correct Answer: Enhance visualization of specific phytochemical classes

Q16. Which chromatographic technique is most appropriate for volatile essential oil profiling from herbal samples?

• Ion-exchange chromatography
• Gas chromatography-mass spectrometry (GC-MS)
• Size-exclusion chromatography
• Paper chromatography

Correct Answer: Gas chromatography-mass spectrometry (GC-MS)

Q17. What does peak purity assessment by diode array detector (DAD/PDA) reveal in herbal analysis?

• Column temperature variations
• Whether a chromatographic peak contains co-eluting components
• The molecular weight of the analyte
• Mobile phase pH

Correct Answer: Whether a chromatographic peak contains co-eluting components

Q18. Which of the following is a common internal standard requirement in quantitative chromatographic assays of herbal extracts?

• It should co-elute with the analyte
• It must be absent from the sample matrix and chemically stable
• It must be a volatile solvent
• It should degrade under analysis conditions

Correct Answer: It must be absent from the sample matrix and chemically stable

Q19. Which factor most affects selectivity between two compounds in chromatography?

• Detector lamp intensity
• Stationary phase chemistry and mobile phase composition
• Sample vial color
• Ambient lighting in lab

Correct Answer: Stationary phase chemistry and mobile phase composition

Q20. In herbal product standardization, what is a major challenge for chromatographic analysis?

• Simplicity of herbal matrices
• Complex multi-component matrices with interfering constituents
• Lack of any natural variability
• Excessively high volatility of all components

Correct Answer: Complex multi-component matrices with interfering constituents

Q21. What is the main advantage of hyphenated techniques (e.g., LC-MS) in herbal standardization?

• Lower instrumentation cost
• Ability to separate and provide structural information for analytes
• No need for sample prep
• Reduced sensitivity

Correct Answer: Ability to separate and provide structural information for analytes

Q22. Which parameter is improved by using smaller particle size stationary phases in HPLC?

• Detector baseline noise
• Column efficiency and theoretical plates
• Mobile phase boiling point
• Sample solubility

Correct Answer: Column efficiency and theoretical plates

Q23. In TLC, a mobile phase of increasing polarity will generally cause which effect on polar analytes?

• They will move further up the plate (higher Rf)
• They will not change position
• They will move less (lower Rf)
• They will decompose

Correct Answer: They will move further up the plate (higher Rf)

Q24. When developing an HPLC method for a herbal marker compound with ionizable groups, which variable is critical to control?

• Column length only
• Mobile phase pH relative to pKa of analyte
• Ambient humidity
• Vial cap color

Correct Answer: Mobile phase pH relative to pKa of analyte

Q25. For quantitative HPLC assays, calibration curves should be evaluated for which linearity criterion?

• Correlation coefficient (r or r2) within acceptable limits and homoscedastic residuals
• Only one calibration point
• Use of a nonlinear single point
• Random scatter without regression

Correct Answer: Correlation coefficient (r or r2) within acceptable limits and homoscedastic residuals

Q26. Which of the following best describes “fingerprinting” in herbal chromatographic analysis?

• Quantifying a single contaminant only
• Generating a comprehensive chromatographic profile representing multiple characteristic peaks
• Measuring temperature of extract
• Determining pH alone

Correct Answer: Generating a comprehensive chromatographic profile representing multiple characteristic peaks

Q27. What is the role of a guard column in HPLC when analyzing complex herbal extracts?

• Increase detector sensitivity
• Protect analytical column from particulates and strongly retained impurities
• Change mobile phase composition
• Reduce sample polarity

Correct Answer: Protect analytical column from particulates and strongly retained impurities

Q28. In liquid chromatography, what does a high plate number (N) indicate?

• Poor separation
• High column efficiency and potentially narrower peaks
• Excessive baseline noise
• Column blockage

Correct Answer: High column efficiency and potentially narrower peaks

Q29. What chromatographic approach can help resolve closely eluting isomers in herbal extracts?

• Using a stationary phase with different selectivity or orthogonal separation (e.g., chiral or different chemistry)
• Decreasing detector gain
• Reducing sample concentration to zero
• Ignoring system suitability

Correct Answer: Using a stationary phase with different selectivity or orthogonal separation (e.g., chiral or different chemistry)

Q30. Which validation attribute ensures the method remains reliable when small deliberate changes are made to chromatographic conditions?

• Robustness
• Specificity
• Accuracy
• LOD

Correct Answer: Robustness

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