Metrohm 892 Professional Rancimat - Manual (Page 39)

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4 Operation
892 Professional Rancimat
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￭ Then transfer 3 g sample material to the reaction vessel using
preheated pipettes.
or
￭ Place the reaction vessel on a scale using a 6.2628.000 holder.
￭ Weigh in the fat as solid.
For this, weigh in 3 g sample material directly in the reaction
vessel and insert it briefly in the heated block of the 892 Profes-
sional Rancimat, so that the fat melts.
2 Checking the filling level
￭ Make sure that the quantity of melted sample material in the
reaction vessel is sufficient so that the air tube is immersed deeply
enough. If this is not the case, add more sample material.
Preparing samples containing oil and fat
Oils and fats made from products containing oil and fat must be extracted
with petroleum ether (low-boiling) while being protected from light as fol-
lows:
1 Crushing the samples
￭ Finely and homogeneously grind oilseed fruit, cocoa beans as well
as other solids in coarse form in a knife mill or another suitable
crushing apparatus (if possible, metal-free).
NOTE
Oil/fat extraction through pressing has not proven effective in
practice.
2 Extraction
￭ Prepare a 300 mL Erlenmeyer flask with standard ground-joint.
￭ Weigh in between 50 and 100 g (depending on the oil/fat con-
tent) of the sample in powder form (e.g. milk powder, cocoa
powder, hazelnut powder) or the finely ground material.
￭ Cover the sample material with a layer of approx. 1 cm of petro-
leum ether (low-boiling).
￭ Extract the oil or fat while continuously stirring for around 12 h
and keeping it protected from light.