Hanna Instruments HI97101 Instruction Manual page 23

Whenever the cuvette is placed into the measurement holder, it must be dry outside
and free of fingerprints, oil or dirt. Wipe it thoroughly with HI731318 microfiber
cleaning cloth or a lint-free wipe prior to insertion.
Shaking the cuvette can generate bubbles in the sample, causing higher readings. To
obtain accurate measurements, remove such bubbles by swirling or by gently tapping
the cuvette.
Do not let the reacted sample stand too long after reagent has been added. For best
accuracy, respect the timings described in each specific method.
It is possible to take multiple readings in a row, but it is recommended to take a new
zero reading for each sample and to use the same cuvette for zeroing and measurement
when possible.
Discard the sample immediately after the reading has been taken, or the glass might
become permanently stained.
All the reaction times reported in this manual are at 25 °C (77 °F). In general, the
reaction time should be increased for temperatures lower than 20 °C (68 °F), and
decreased for temperatures higher than 25 °C (77 °F).
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