Semi-Micro Osmometer K-7400S instructions, V3700
Operation 25
8. Water which is stored in polyethylene bottles over a longer period
could be dicult to be super-cooled. If such diculties may occur, we
recommend a storage in glass bottles.
9. Make sure that the sample material is homogeneous. If the measure-
ment result has to be reproduced with the same sample, it has to
be mixed with the stirring wire before each further measurement.
As ice does not contain salines and floats on top while unfreezing, it
results in a concentration gradient which has to be removed before
measure ment.
10. Evaporation can increase the concentration of dissolved particles
which leads to increase of osmolality of a solution. Calibration solu-
tions should be used not longer than 30 – 60 min after the tubes were
opened. We recommend using KNAUER calibration solutions which
are mentioned in chapter „13. Repeat orders“ on page 42.
11. After finishing all measurements, the osmometer should be swit-
ched o, because a permanent operation reduces the lifespan of the
device. If the device is switched on but unused for a longer period, it
may occur that some water from room air is condensed in the cooling
cavity. It should be removed carefully with a dry, lint-free tissue prior
to the next measurement.
12. The stirring wire triggers the reproducible freezing and is set optimal
in the factory. Make sure that you do not bend the wire while atta-
ching the sample tubes and cleaning.
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