Hanna Instruments HI 83211 - Manual (Page 10)

10
• Pay attention to push the cuvette completely down in the holder and to align the white point on the
cap to the indexing mark on the meter.
• 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.
• Each time the cuvette is used, the cap must be tightened to the same degree.
• Whenever the cuvette is placed into the measurement cell, it must be dry
outside, and free of fingerprints, oil or dirt. Wipe it thoroughly with
HI 731318 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.
• Do not let the reacted sample stand too long after reagent is 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 (for most precise results follow
the measurement procedures carefully).
• Discard the sample immediately after the reading is 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).
INTERFERENCES
• In the method measurement section the most common interferences that may be present in an average
sample matrix have been reported. It may be that for a particular treatment process other compounds
do interfere with the method of analysis.