Preparing A Sample - KERN and SOHN DLB 160-3A Mode D'emploi

13.4 Preparing a sample

Prepare one sample at a time for measuring. This prevents the sample from exchanging
moisture with its surroundings. If several samples have to be taken at the same time,
they should be packed in airtight boxes so that they do not undergo changes during
storage.
To receive reproducible results, spread the sample thinly and evenly on a sample dish.
Patchy spreads will produce inhomogeneous heat distribution in the sample to be dried
resulting in incomplete drying and increased measuring time. Sample clusters generate
increased heating of the upper layers resulting in combustion or incrustation. The high
layer thickness or possibly arising incrustation makes it impossible for the moisture to
escape from the sample. Due to this residual moisture, measured results calculated in
this way will not be comprehensible or reproducible.
Preparing a sample from solids:
• Spread powdery or grainy samples evenly on the sample dish.
• Grind coarse samples using a mortar or a shredder. When grinding the sample avoid
any heat supply as this may cause loss of humidity.
Preparing a sample from liquids:
For liquids, pastes or melting samples we recommend to use a glass fibre filter. The glass
fibre filter has the following advantages:
• Even distribution thanks to capillary attraction
• no formation of droplets
• fast evaporation due to a greater surface
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