Which practice should not be done when using a cuvette?

• A. Use a Brush to Clean the Insides of the Cuvette
• B. Fill the Cuvette About 3/4 Full of the Solution You Wish to Test.
• C. Wipe the Outside of the Cuvette with a Lint-Free, Soft Tissue to Remove Any Moisture or Fingerprints from the Outside Surface.
• D. Do Not Clean Your Cuvettes in an Ultrasonic Cleaning Bath.

Answer: (A)

The main idea is keeping cuvettes clean without damaging their precise optical surfaces. Using a brush to clean the inside of a cuvette should be avoided because the interior is a very smooth, delicate surface. A brush can scratch glass or quartz, or leave fibers and particles behind, all of which scatter or absorb light and distort spectrophotometer readings.

The other practices align with good cuvette care. Filling the cuvette to about three-quarters helps prevent spills and keeps the solution fully within the light path without sloshing or creating too much meniscus. Wiping the outside with a lint-free tissue removes moisture and fingerprints that could alter light transmission. Cleaning with an ultrasonic bath is something some labs use, but it should be done only if the cuvette material and design tolerate it and according to manufacturer guidelines.