In spectrophotometric analysis, a blank solution is used as a reference to ensure accurate measurements.
Role of a Blank Solution:
- Zeroing the Instrument
- The blank sets the baseline absorbance to zero.
- This ensures that only the absorbance of the analyte is measured, not the solvent or cuvette.
- Corrects for Solvent and Cuvette Effects
- Solvents and cuvettes can absorb some light themselves.
- Using a blank eliminates their contribution to the measurement.
- Improves Accuracy
- Helps prevent false readings due to impurities, solvents, or instrument noise.
- Provides a Reference for Comparison
- The sample’s absorbance is measured relative to the blank, giving the true absorbance due to the substance being analyzed.
In short:
A blank solution acts as a zero reference in spectrophotometry, correcting for light absorption by the solvent and cuvette so that only the analyte’s absorbance is measured accurately.