Introduction: Qualification of DSC MCQs With Answer is designed for M.Pharm students to strengthen their understanding of Differential Scanning Calorimetry (DSC) qualification as applied in pharmaceutical validation. The set covers key concepts such as IQ/OQ/PQ stages, temperature and enthalpy calibration, selection of reference standards, performance verification, acceptance criteria, and common sources of error. These questions emphasize practical aspects—sample preparation, heating rates, purge gas effects, baseline stability, and software controls—relevant to ensuring accurate thermal analysis data in drug development and quality control. Use this quiz to self-assess readiness for lab responsibilities and regulatory documentation related to DSC qualification.
Q1. What is the primary purpose of Instrument Qualification (IQ) for a DSC used in a pharmaceutical laboratory?
- To verify method suitability for a specific assay
- To demonstrate that the DSC is installed correctly and all components are present
- To test long-term stability of sample materials
- To calibrate the enthalpy using reference standards
Correct Answer: To demonstrate that the DSC is installed correctly and all components are present
Q2. Which calibration standard is most commonly used for temperature calibration of DSC instruments?
- Benzoic acid
- Indium
- Potassium chloride
- Sucrose
Correct Answer: Indium
Q3. In DSC qualification, what does PQ (Performance Qualification) principally assess?
- Whether the instrument was shipped undamaged
- Whether the instrument meets user requirements under real-world conditions
- Whether installation paperwork is completed
- Whether reference materials are available
Correct Answer: Whether the instrument meets user requirements under real-world conditions
Q4. Which of the following is a critical acceptance criterion during DSC enthalpy calibration?
- Peak width of the endotherm must be less than 10 °C
- The measured enthalpy of fusion should be within a predefined percent of the certified value
- The baseline must be perfectly horizontal with zero noise
- Heating rate should be above 50 °C/min
Correct Answer: The measured enthalpy of fusion should be within a predefined percent of the certified value
Q5. During DSC qualification, which factor most directly influences apparent peak temperature and must be controlled?
- Color of the sample pan
- Heating rate
- Ambient humidity of the lab
- Manufacturer of the balance
Correct Answer: Heating rate
Q6. Which purge gas parameter is typically verified during DSC OQ to ensure stable baseline and reproducible results?
- Purity of sample pans
- Flow rate and gas type (e.g., nitrogen or helium)
- Time of day when the experiment is run
- Color of the DSC enclosure
Correct Answer: Flow rate and gas type (e.g., nitrogen or helium)
Q7. For enthalpy calibration, why are multiple calibration points (different temperature standards) recommended during qualification?
- To validate the linearity of temperature and heat flow responses across the measurement range
- To reduce the weight of the sample
- To verify the color stability of standards
- To increase sample throughput
Correct Answer: To validate the linearity of temperature and heat flow responses across the measurement range
Q8. Which property of indium makes it a preferred reference material for DSC temperature calibration?
- Very high melting point above 500 °C
- Sharp, well-defined melting point and well-known enthalpy of fusion
- It is a polymer with multiple transitions
- It sublimes easily at low temperature
Correct Answer: Sharp, well-defined melting point and well-known enthalpy of fusion
Q9. What is the main reason to perform baseline determination as part of DSC qualification?
- To calibrate the mass of the sample
- To assess instrument noise, drift and stability independent of sample signal
- To identify the color of thermal events
- To determine the melting point of unknown compounds
Correct Answer: To assess instrument noise, drift and stability independent of sample signal
Q10. Which DSC operational parameter should be documented and controlled to ensure reproducible results during qualification?
- Size of the benchtop the instrument sits on
- Sample mass, pan type, heating rate and purge gas conditions
- Brand of laboratory gloves used
- Color of sample labeling tape
Correct Answer: Sample mass, pan type, heating rate and purge gas conditions
Q11. In qualification, what does heat flow calibration verify?
- That the DSC door closes properly
- That the instrument reports accurate enthalpy values (mW to J conversion) against certified standards
- That software update history is present
- That sample pans are magnetically responsive
Correct Answer: That the instrument reports accurate enthalpy values (mW to J conversion) against certified standards
Q12. Which of the following is a common reference material used for low-temperature calibration of DSC near 0 °C?
- Gallium
- Lead
- Gold
- Polyethylene
Correct Answer: Gallium
Q13. Why is reproducibility testing (repeatability) important in DSC PQ runs?
- To confirm that different instruments give wildly different results
- To demonstrate that measurements under the same conditions produce consistent thermal parameters
- To reduce the need for standard operating procedures
- To increase the heating rate for speed
Correct Answer: To demonstrate that measurements under the same conditions produce consistent thermal parameters
Q14. Software validation is part of DSC qualification. Which aspect is most critical to validate?
- Graphical color schemes available in the software
- Data acquisition integrity, calculation algorithms for peak onset, peak area, and audit trail
- Default user wallpaper
- Keyboard language options
Correct Answer: Data acquisition integrity, calculation algorithms for peak onset, peak area, and audit trail
Q15. During OQ, a DSC shows a systematic offset in measured melting temperature across standards. What is the likely corrective action?
- Replace all sample pans with plastic ones
- Adjust temperature calibration (slope/intercept) and re-calibrate using certified standards
- Increase sample mass until the offset disappears
- Change the room lighting to daylight lamps
Correct Answer: Adjust temperature calibration (slope/intercept) and re-calibrate using certified standards
Q16. What effect does excessive sample mass generally have on DSC peak shapes and measured temperatures?
- No effect; DSC is mass-independent
- It can broaden peaks and cause apparent shifts in peak temperature due to thermal gradients
- It sharpens peaks and lowers baseline noise
- It converts endotherms into exotherms
Correct Answer: It can broaden peaks and cause apparent shifts in peak temperature due to thermal gradients
Q17. For qualification documentation, which element is essential to include with each calibration or verification run?
- Favorite color of the analyst
- Date, analyst name, instrument ID, raw data, calculated results and acceptance statement
- List of unrelated experiments in the lab
- Number of coffee breaks taken during the day
Correct Answer: Date, analyst name, instrument ID, raw data, calculated results and acceptance statement
Q18. Which DSC mode separates two cells each heated by independent heaters and is often used in high-performance instruments?
- Heat flux DSC
- Power compensation DSC
- Thermogravimetric DSC
- Infrared DSC
Correct Answer: Power compensation DSC
Q19. Which performance test specifically checks the instrument’s sensitivity to small heat effects during qualification?
- Temperature ramp speed test
- Baseline noise and minimum detectable heat flow (sensitivity) test
- Sample tray capacity test
- External light interference test
Correct Answer: Baseline noise and minimum detectable heat flow (sensitivity) test
Q20. If a DSC shows drift in baseline over long isothermal holds during PQ, what is a likely root cause to investigate?
- Insufficient sample cooling prior to run
- Instrument thermal equilibration issues, poor purge gas stability, or electronics drift
- Incorrect font size in software reports
- Excessive labeling on sample vials
Correct Answer: Instrument thermal equilibration issues, poor purge gas stability, or electronics drift
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.
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