Absorbance accuracy in spectrophotometry is checked using which combination?

• A. Filters and a solution with no absorbance
• B. Gas discharge lamp and cuvette
• C. Holmium oxide solution
• D. Sharp cutoff filters

Answer: (A)

Absorbance accuracy hinges on ensuring the instrument’s baseline is correct and its response to light attenuation is reliable. To check this, you use a solution with no absorbance to set the zero point so the measured absorbance should be zero when no absorber is present. Pairing that with filters—specifically neutral density filters that attenuate light without introducing spectral features—lets you verify the photometric response across different light intensities. If the blank truly reads zero and the instrument’s readings scale correctly with the known attenuation, you can trust the absorbance measurements over the instrument’s range. The other options address different aspects: holmium oxide solution is used for confirming wavelength accuracy, while gas discharge lamp with a cuvette or sharp cutoff filters relate to hardware setup or spectral selection rather than checking absorbance accuracy directly.