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6.3. CUVETTE PREPARATION
Proper mixing is very important for reproducibility of the measurements. The proper mixing
technique for each method is listed in the method procedure.
(a) Invert the cuvette a couple of times or for a specified time: hold the cuvette in the vertical
position. Turn the cuvette upside‑down and wait for all of the solution to flow to the cap end,
then return the cuvette to the upright vertical position and wait for all of the solution to flow to
the cuvette bottom. This is one inversion. The correct speed for this mixing technique is
10‑15 complete inversions in 30 seconds.
This mixing technique is indicated with “invert to mix” and the following icon:
(b) Shaking the cuvette, moving the cuvette up and down. The movement may be gentle or
vigorous. This mixing method is indicated with “shake gently” or “shake vigorously”, and one
of the following icons:
In order to avoid reagent leaking and to obtain more accurate measurements,
close the cuvette first with the supplied HDPE plastic stopper
and then the
black cap.
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
or
a lint‑free cloth 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.
shake gently
shake vigorously
PHO
TOMETER MODE