Rice Lake MA37 Sartorius Moisture Analyzer User Manual
Page 15
Preparation
Before drying a sample, you must carry out the following preparations:
– Adjust against the existing measurement system
– Prepare the sample
– Set the drying program parameters
Adjusting against an Existing Measurement System
A moisture analysis method often replaces another drying method (such as oven
drying method) because it is simple to use and requires shorter analysis time . In this
case, you should adapt this method to that of the moisture analyzer in order to
obtain values comparable to those yielded by your standard reference method .
Perform parallel measurements:
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Take a fresh sample and divide it in half
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Determine the moisture content of the first half using your standard method
of analysis
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Determine the moisture content of the second half using the following settings:
– Fully automatic mode for the switch-off criterion
– Lower temperature settings than for the oven drying method
– Temperature setting for organic substances: 80–100°C
– Temperature setting for inorganic substances: 140–160°C
If the result of the second analysis does not correspond to that of the first:
1 . First, repeat the analysis using a different temperature setting
2 . Then use the semi-automatic mode for the switch-off criterion (for example with
a different loss rate per 24 s)
Change the switch-off criterion if required:
– Increase end-point recognition: Set the parameter to 2 mg/24 s or 1 mg/24 s
– Decrease end-point recognition: Set the parameter to 10 mg/24 s or 20 mg/24 s
Preparing the Sample
Select a sample:
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Select a representative part of the whole substance as a sample .
– Choose a representative number of individual samples for quality control
– Choose enough samples to indicate a trend for in-process control
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If required, homogenize the product before a sample is taken by:
– Mixing or stirring
– Taking several samples from different areas of the product
– Taking several samples at defined intervals
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Take only one sample at a time for a given analysis and prepare it as quickly as
possible . In this way, it will not lose or gain moisture as a result of the ambient
conditions .
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If several samples need to be taken simultaneously, the samples must be sealed
in airtight containers to ensure that the storage conditions do not alter the state
or condition of the samples:
– Warm or highly volatile substances lose their moisture very quickly .
– If you store the samples in a container, the moisture can condense on the walls
of the container .
– If the container is too big and not filled completely, the sample can exchange its
moisture with the air remaining in the container .
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Operating Instructions Moisture Analyzer MA37
Basic Principles