It is important that the sample does not contain any debris.
Whenever the cuvette is placed into the measurement cell, it must be dry outside, and completely free of fingerprints, oil and dirt. Wipe it thoroughly with HI 731318 or a lint-free cloth prior to insertion.
Shaking the cuvette can generate bubbles, causing higher readings. To obtain accurate measurements, remove bubbles by swirling or by gently tapping the cuvette.
Do not let the reacted sample stand for too long after reagent is added, as accuracy will be affected.
After the reading it is important to immediately discard the sample, otherwise the glass might become permanently stained.