SampleExtraction andPreparation
Soil Samples
•
InMethod8095, analytes of interest are extracted fromsoil and sediment
samples using the same acetonitrile extractionwith ultra-sonicationprocedure
as described inMethod8330.
Samples are air-dried at roomtemperature or
cooler to a constant weight.
Then the samples are screenedwith a colorimetric
test, such as EPAMethod8515, to determine if theycontain toomuch
explosive residue tobe safelygroundwith amortar and pestle. If the sample
contains less than1%explosive residue, generally it is considered safe to be
groundwith amortar and pestle.
Two grams of the finelyground soil are
extracted using10milliliters of acetonitrile in a cooledultra-sonicationbath
for 18 hours.
The acetonitrile extracts are then dried and filtered before
analysis.
•
Amain difference in sample preparation forGC is that the samples are not
diluted 1:1with reagent water prior tobeing injected, as is the case forHPLC
samples
