Metrohm 892 Professional Rancimat - Manual (Page 41)

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4 Operation
892 Professional Rancimat
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NOTE
If the isolated oil/fat samples are not immediately analyzed, you
have to store the samples in a cool place and protected from
light; for storing the samples, you should cover them in their ves-
sels with a nitrogen layer. This type of storage does not provide
complete protection against unintended and uncontrolled changes
in the oxidation stability, but it represents a useful preservation in
many cases.
You can find further information on the treatment of oil and fat samples
in Rancidity in Foods, Allen J.C., Hamilton R.J., Applied Science Publish-
ers, London and New York, 1983.
Preparing emulsion fats
You can use emulsion fats like pure substances and prepare them as fol-
lows:
1 Weighing in the sample
￭ Weigh in the sample.
NOTE
As the water evaporates right at the beginning of the analysis and
is carried away by the air blown through, you have to use corre-
spondingly more sample material.
2 Mounting the foam barrier
￭ Mount the foam barrier (see figure 9, page 17), as the samples
can foam heavily.
NOTE
If the emulsion fat samples are not immediately analyzed, you
need to store the samples in a cool place and protected from
light; for storing the samples, you should cover them in their ves-
sels with a nitrogen layer. This type of storage does not provide
complete protection against unintended and uncontrolled changes
in the oxidation stability, but it provides useful preservation in
many cases.