3 • Operation and Maintenance
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Guidelines for Grinding
• For an efficient extraction to occur, the solvent must make contact
with the target analytes. The more surface area that can be exposed in
a sample, the faster extraction will occur. Therefore, samples with
large particle sizes should be ground prior to extraction. Often a large,
representative sample can be ground, and then weighed portions of
the ground sample can be used for extraction.
• Soil and sediment samples usually do not need to be ground, but it
may be necessary to remove stones or sticks from the samples prior to
extraction.
• Polymer samples must be in a ground state for an efficient extraction
of additive compounds. Materials such as polymers and rubbers are
best ground at reduced temperatures; for example, liquid nitrogen.
• Animal or plant tissue samples can be homogenized using any
procedure such as a blender or tissue homogenizer.
Sample Preparation by Grinding
Grind the sample with any of the following tools: a conventional mortar
and pestle, an electric grinder, or an electric mill. For the most efficient
extraction, grind until particles are smaller than 1 mm.
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