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MB62 Instruction Manual
Treating the sample during drying
Occasionally, following recording of the initial weight of the sample and before the actual
drying, the test substance is subjected to further treatment. The Moisture Analyzer from
OHAUS offers this possibility in the "manual" operating mode.
Such applications could include:
• Mixing of quartz sand: moisture which vaporizes during the mixing of the sample is
correctly taken into account in the final result.
• Coagulation of protein by dropwise addition of alcoholic solutions. This prevents skin
formation during drying. Added solvent is not recorded in the final result.
• Formation of readily volatile azeotropes by addition of solvents insoluble in water (e.g.
xylene, toluene).
CAUTION:
Risk of Fire or Explosion! Addition of solvents can lead to the formation of flammable
or even explosive mixtures. With applications of this type, you should thus work with
extremely small amounts of samples and with the necessary care. In cases of doubt,
a careful risk analysis must be performed.
Selection of the optimum sample weight
The sample weight has an influence on both the accuracy of the measurement results
and the measurement time. With large amounts of samples, a great deal of water must
vaporize and the moisture determination takes longer.
To keep the measurement time as short as possible, we advise you choose a low weight
for your sample, but not so low that attainment of the required measurement accuracy is
no longer possible.
Influence of the sample weight on the repeatability of the
results
Sample weight influences the repeatability of the Moisture Analyzer. The repeatability
always becomes worse with decreasing sample weight. The relation between sample
weight and repeatability is shown in the following table:
Sample Weight
3g
10g
The preceding table is based on the assumption that the sample is ideal, homogeneous
and its moisture can always be separated completely and free from decomposition (e.g.
moist sand). Deviations always comprise the uncertainty, which depends on the sample,
Repeatability
±0.10%
±0.018%
EN-23
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