Micromeritics AccuPyc 1330, Operator'S Manual, Page: 28 / 115

Preparing and Loading a Sample
Preparing the sample is the first step in obtaining accurate results from the
pycnometer. Samples must be free of moisture in order to obtain true sample
weight and to avoid the distorting effect of water vapor on the volume meas-
urement. The following procedures are recommended; however, modifications
may be necessary for some materials. Heat sensitive materials may have to
be dried by long-time exposure to silica gel, freeze drying, etc. Materials
having a low melting point may be dried using the purge process. In this
case, do not weigh the sample and cup until after the purge and analysis have
been completed.
The important point to keep in mind is that each step should be conducted to
avoid exposure of the dried sample to atmospheric moisture. This means
weighing as rapidly as possible and installing in the instrument without unnec-
essary delay.
Keep the cap on the cell chamber except when actually inserting or re-
moving a sample. If the chamber remains uncapped, temperature insta-
bility will occur which could affect analysis results.
1. Weigh the empty sample cup. (If volume only is to be measured, you
may skip this step).
2. Place a quantity of sample in the cup. Use as large a quantity of sample
as possible; we recommend that the cup be at least two-thirds full. Pack
powders and fluffy materials (if permissible) to obtain maximum sample
weight in the cup.
3. Place the sample cup with sample in a drying oven. The amount of time
the sample must be heated depends on the material and the temperature
it will tolerate; this may have to be established by other tests.
4. Remove the sample cup from the oven and transfer it to a desiccator pro-
vided with active desiccant. Allow it to cool until near room tempera-
ture. In the steps which follow, minimize air exposure of the sample.
5. Weigh the cup and sample and record the weight. Subtract the empty
sample cup weight from the sample cup plus sample weight to deter-
mine the sample weight. (If volume only is to be measured, you may
skip this step.)
Preparing and Loading a Sample AccuPyc 1330
3-2 September 1996