Which instrument uses a cuvette?

• A. Flame-AAS
• B. UV-Vis Spectrophotometer
• C. Gas Chromatograph
• D. pH Meter

Answer: (B)

Cuvettes are small, transparent containers that hold liquid samples so light can pass through them and be measured for absorption or transmission. This is essential in UV-Vis spectroscopy, where the instrument shines light through the sample in the cuvette and detects how much is absorbed at a chosen wavelength. The amount of absorption relates to the sample’s concentration via the Beer-Lambert law, with the cuvette’s path length also influencing the measurement.

In other techniques, the sample is prepared or introduced differently: flame atomic absorption uses a sample aerosol in a flame, gas chromatography injects and vaporizes a sample into a separation column, and a pH meter uses an electrode in solution to measure hydrogen ion activity. These setups do not involve light passing through a cuvette, so a cuvette isn’t used there.