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GENERAL TIPS FOR ACCURA
TE MEASUREMENTS
9. GENERAL TIPS FOR ACCURATE MEASUREMENTS
9.1. CUVETTE PREPARATION
The cuvette is part of the optical system as the light reaches the sample by passing through the
cuvette glass. Measurements are affected by dirt, dust, scratches, or fingerprints present on the cuvette
surface, and so special care must be taken during sample preparation.
Handling & Cleaning
• Cuvettes should be free of scratches or cracks. If any present, the cuvettes should be replaced.
• Part of regular maintenance, cuvettes should be washed with acid and rinsed thoroughly with
distilled or deionized water.
• Cuvettes should be completely dry before use or storage.
• For long term storage, cuvettes should be stored with caps on, in separate boxes (or with separators
between them) to avoid scratches.
• When handling the cuvettes only the cap or the top side (over the horizontal line) should be touched.
Preparation
• Only use clean cuvettes.
• When inserted, it must be dry outside, completely free of fingerprints or dirt.
• If the cuvette is not indexed, position the cuvette such that the factory mark is aligned with the
mark on top of the instrument.
Note:
If the cuvette is indexed, use the index for correct positioning.
Cuvette Oiling
To hide minor imperfections and scratches, the outside of a clean, dry cuvette should be oiled using
supplied silicone oil. For low turbidity samples (< 1 FNU) scratches can alter turbidity readings.
The silicone oil has the same refractive index as the glass and does not alter the turbidity readings.
