Sartorius MA35, Руководство по эксплуатации

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18
t
Use an appropriate tool for grinding
the sample .
t
If the sample is liquid containing solids,
use one of the following tools:
– Glass stirrer
– Spoon
– Magnetic stirrer
Use a disposable sample pan
t
Use only Sartorius disposable sample
pans (inner diameter of 90 mm) . Reusing
sample pans leads to poor repeatability
of results:
– After cleaning, sample residues can still
remain on the pan .
– Residues from cleaning agents can
evaporate during the next moisture
analysis .
– Scratches and grooves made during
cleaning result in damage that forms
points of attack for hot, rising air
produced during the drying process
(more pronounced buoyancy) .
Distribute the sample on the
sample pan
t
Distribute the sample on the sample pan
in a thin, even layer (height: 2 to 5 mm,
weight: 5 to 15 g); otherwise:
– A sample applied unevenly will result in a
nonuniform distribution of heat
– The sample will not be dried completely
– The analysis time will be unnecessarily
extended
– The sample will burn or a crust/skin will
form on its surface as a result of a very
thick layer
– The crust makes it difficult or impossible
for moisture to escape from the sample
during the drying process
– An uncertain and unknown quantity of
moisture will remain in the sample
t
Apply liquid samples, pasty samples, or
samples that can melt to a glass-fiber
filter (order no . 6906940); this provides
the following benefits:
– Uniform distribution due to the capillary
effect
– Liquids are prevented from beading
together and forming drops
– With larger surfaces, the moisture can
evaporate faster
– Colorless/transparent samples do not
reflect
– Considerably more convenient than the
“sea-sand method”
When drying samples containing sugar,
a crust or skin can form and seal the
surface . A glass-fiber filter is particularly
useful in such cases . The moisture can
evaporate downwards through the
surface of the filter . Crust/skin formation
can be prevented or limited by placing
the glass-fiber filter on top of the
sample .
t
Cover solid, heat-sensitive samples with
a glass-fiber filter (order no . 6906940);
this provides the following benefits:
– Gentle heating, because the sample
surface is shielded from excessive heat
– Higher temperature setting can be
selected
– Uniformity of the sample surface
– Fast evaporation of the moisture
– Excellent repeatability for samples
containing fat