Qualification of UV-Visible spectrophotometer MCQs With Answer

Qualification of UV-Visible spectrophotometer MCQs With Answer

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Qualification of UV-Visible Spectrophotometer MCQs With Answer

This collection of multiple-choice questions is designed specifically for M.Pharm students studying pharmaceutical validation. It focuses on the qualification and performance verification of UV-Visible spectrophotometers, covering IQ/OQ/PQ concepts, critical performance tests (wavelength accuracy, photometric accuracy, stray light, resolution, baseline stability), calibration standards, documentation and routine checks. The questions probe deeper than basic definitions, addressing practical standards, test procedures, acceptance criteria and the impact of instrument parameters on analytical results. Use these MCQs to strengthen your understanding of instrument qualification requirements, prepare for exams, and build confidence in designing and evaluating validation protocols for UV-Vis instruments used in pharmaceutical analysis.

Q1. What is the primary objective of instrument qualification (IQ/OQ/PQ) for a UV-Visible spectrophotometer?

  • To ensure the software is the latest version
  • To demonstrate the instrument is installed correctly and performs according to manufacturer claims and user requirements under operational and routine conditions
  • To certify the laboratory personnel are trained
  • To maximize instrument run time

Correct Answer: To demonstrate the instrument is installed correctly and performs according to manufacturer claims and user requirements under operational and routine conditions

Q2. Which activity is the main focus of Installation Qualification (IQ) for a UV-Vis spectrophotometer?

  • Verifying analytical method linearity
  • Documenting that the instrument, accessories, and utilities are installed according to manufacturer specifications and site requirements
  • Checking long-term performance under routine sample load
  • Comparing results between two different instruments

Correct Answer: Documenting that the instrument, accessories, and utilities are installed according to manufacturer specifications and site requirements

Q3. Operational Qualification (OQ) for a UV-Vis spectrophotometer normally assesses:

  • User training completion
  • Instrument performance across specified operating ranges such as wavelength accuracy, photometric accuracy, stray light and baseline stability
  • Sample storage conditions
  • Regulatory submission documents

Correct Answer: Instrument performance across specified operating ranges such as wavelength accuracy, photometric accuracy, stray light and baseline stability

Q4. Performance Qualification (PQ) is best described as:

  • Testing instrument performance using manufacturer’s service tools only
  • Verifying the instrument produces acceptable results with real routine samples under normal laboratory conditions
  • Installing the instrument in the laboratory
  • Updating instrument firmware

Correct Answer: Verifying the instrument produces acceptable results with real routine samples under normal laboratory conditions

Q5. Which standard material is commonly used for verifying wavelength accuracy of a UV-Visible spectrophotometer?

  • Potassium dichromate solution
  • Holmium oxide glass filter
  • Neutral density filter
  • Activated carbon

Correct Answer: Holmium oxide glass filter

Q6. For photometric accuracy checks in the UV region, a commonly used reference material or solution is:

  • Potassium dichromate solution
  • Holmium oxide filter
  • Silica gel
  • Deionized water only

Correct Answer: Potassium dichromate solution

Q7. Which test substance or approach is commonly employed to evaluate stray light in UV-Vis spectrophotometers?

  • Potassium chloride (KCl) solution or appropriate cut-off filter to assess transmission below cutoff wavelengths
  • Holmium oxide to assess stray light directly
  • Using only deionized water at 500 nm
  • Measuring room light with a lux meter

Correct Answer: Potassium chloride (KCl) solution or appropriate cut-off filter to assess transmission below cutoff wavelengths

Q8. What does spectral resolution of a UV-Vis spectrophotometer describe?

  • The instrument’s physical size
  • The ability to distinguish two closely spaced spectral peaks as separate signals
  • The maximum absorbance measurable
  • The number of wavelengths stored in memory

Correct Answer: The ability to distinguish two closely spaced spectral peaks as separate signals

Q9. How does reducing the instrument spectral bandwidth (slit width) typically affect measurements?

  • It increases stray light and reduces resolution
  • It narrows peaks and improves resolution but can reduce signal intensity and signal-to-noise ratio
  • It increases detector sensitivity without other effects
  • It has no observable effect on spectra

Correct Answer: It narrows peaks and improves resolution but can reduce signal intensity and signal-to-noise ratio

Q10. Baseline stability in UV-Vis qualification is assessed by monitoring:

  • Absorbance drift over a defined time period with a blank in the sample holder
  • Only the wavelength readout once
  • Temperature changes in the room only
  • The color of the instrument casing

Correct Answer: Absorbance drift over a defined time period with a blank in the sample holder

Q11. A typical system suitability test for linearity of a UV-Vis method involves:

  • Measuring a single high-concentration standard once
  • Analyzing a series of standards at different concentrations and calculating correlation coefficient or regression statistics
  • Only checking the instrument’s serial number
  • Running only a solvent blank

Correct Answer: Analyzing a series of standards at different concentrations and calculating correlation coefficient or regression statistics

Q12. Noise and signal-to-noise ratio (S/N) are assessed by:

  • Measuring extreme temperature fluctuations
  • Recording the standard deviation of baseline absorbance and dividing signal height by baseline noise
  • Counting the number of scans averaged only
  • Measuring only wavelength accuracy

Correct Answer: Recording the standard deviation of baseline absorbance and dividing signal height by baseline noise

Q13. Which procedure best evaluates repeatability (precision) of absorbance measurements on a UV-Vis?

  • Measuring different samples once each
  • Performing multiple consecutive measurements of the same standard solution and calculating %RSD
  • Changing cuvettes between each measurement intentionally
  • Only verifying documentation completeness

Correct Answer: Performing multiple consecutive measurements of the same standard solution and calculating %RSD

Q14. Wavelength repeatability is tested by:

  • Measuring the same known absorption peak multiple times and assessing variation in recorded peak wavelength
  • Changing lamps between measurements
  • Only inspecting the lamp visually
  • Measuring baseline noise at a single wavelength

Correct Answer: Measuring the same known absorption peak multiple times and assessing variation in recorded peak wavelength

Q15. Which approach is commonly used to demonstrate photometric linearity of a UV-Vis system?

  • Using serial dilutions of a standard solution covering the intended absorbance range and verifying linear response
  • Relying only on manufacturer claims about linearity
  • Using a single neutral density filter only
  • Measuring blank solvent at multiple wavelengths

Correct Answer: Using serial dilutions of a standard solution covering the intended absorbance range and verifying linear response

Q16. Why is lamp warm-up time important before performing qualification tests?

  • Lamps are irrelevant for modern spectrophotometers
  • Lamp output intensity and wavelength output stabilize after warm-up, reducing baseline drift and improving repeatability
  • It helps to cool the instrument down
  • Warm-up time is only required for fluorescence instruments

Correct Answer: Lamp output intensity and wavelength output stabilize after warm-up, reducing baseline drift and improving repeatability

Q17. Qualification documentation for a UV-Vis spectrophotometer should typically include:

  • Only the manufacturer’s brochure
  • Installation records, test procedures, raw data, acceptance criteria, calibration certificates and traceability information
  • Only the purchase invoice
  • Only user training sign-off

Correct Answer: Installation records, test procedures, raw data, acceptance criteria, calibration certificates and traceability information

Q18. A full requalification of a UV-Vis spectrophotometer is generally required when:

  • Only small routine maintenance like cleaning the exterior is performed
  • The instrument is relocated, major repairs or optical component replacements occur, or significant software updates are installed
  • You change the brand of cuvettes used
  • You change analysts but not the instrument

Correct Answer: The instrument is relocated, major repairs or optical component replacements occur, or significant software updates are installed

Q19. Why is use of NIST-traceable reference standards important in UV-Vis qualification?

  • They are cheaper than other standards
  • They provide traceability to national measurement standards and support defensible calibration and acceptance decisions
  • They eliminate the need for any laboratory records
  • They are required only for visual inspections

Correct Answer: They provide traceability to national measurement standards and support defensible calibration and acceptance decisions

Q20. How does stray light typically affect measurements of high-absorbance samples in UV-Vis analysis?

  • It increases the measured absorbance leading to false high values
  • It causes measured absorbance to be artificially low and can produce non-linearity at high absorbance values
  • It has no effect at high absorbance
  • It only affects visible wavelength measurements above 700 nm

Correct Answer: It causes measured absorbance to be artificially low and can produce non-linearity at high absorbance values

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