ing. For the aqueous spiked samples, a 0.100-mL
Heated equilibrium HS/GC analysis (H-HS)
aliquot was removed from each 5 days after we
Ampoules containing laboratory spiked soil
initiated extraction. Each aliquot was transferred
were transferred to empty auto sampler VOA vials,
to an auto sampler vial containing 10 mL of Type
which were then capped. Once the vials were her-
1 water. Using this same procedure, we did analy-
metically sealed, the ampoules were broken and
the soil was completely dispersed by careful hand
ses after various extraction times, ranging from
shaking. In all cases the samples were analyzed
less than 2 hours to 79 days (Table 4) for the vapor-
on the same day that the ampoules were broken;
fortified soils. Before HS vapors were removed
after the sample was heated to 60C for 50 min-
from the VOA vials containing the aqueous-MeOH
solutions, they were held for 20 minutes at 25C.
utes, HS vapors were removed. This procedure is
consistent with that described in the Draft State-
ment of Work for Quick Turnaround Analysis (U.S.
Tetraglyme extraction
EPA 1993).
Samples extracted with tetraglyme used the
same solvent volumes and were analyzed using
Aqueous dispersionextraction in a NaCl-saturated
the same procedure as described for MeOH. For
the aqueous spiked samples, a 0.500-mL aliquot
HS/GC analysis (Aq-NaCL sat'd-HS)
was transferred 6 days after we initiated the ex-
traction. These aliquots were placed into VOA vi-
An aqueous dispersionextraction solution was
als, and 9.5 mL of Type 1 NaCl-saturated water
prepared by acidifying 500 mL of Type 1 water
with H3PO4 to pH 2, then adding 180 g of NaCl;
was added. For the vapor-fortified soils, 0.100-mL
10 mL of this solution was transferred to an auto
aliquots were transferred to VOA vials containing
sampler VOA vial and an ampoule of spiked soil
10 mL of Type 1 water. As for MeOH, several
was added. Once the vials were sealed, the am-
extraction periods were used (Table 4).
poules were broken and their contents complete-
ly dispersed. These samples were analyzed 1 day
Poly(propylene)glycol extraction
after the ampoules were broken when they were
Only soil samples prepared for the second
spiked with an aqueous solution (experiment I),
vapor fortification experiment (experiment III)
and within 2 hours when they were vapor forti-
were extracted with PPG. Extraction and analysis
fied (experiment III). Before HS vapors were
were identical to those described for MeOH and
removed, the soil water slurry was heated to 85C
tetraglyme.
for 60 minutes. This sample preparation and anal-
ysis procedure is consistent with that currently
Analysis
described in draft Method 5021 (U.S. EPA 1986).
All samples were analyzed with a HS auto sam-
pler (Tekmar 7000) coupled to a GC (SRI model
Aqueous dispersionextraction in a solution acidified
8610-0050) equipped with a 15-m DB1 0.53-mm
i.d. capillary column and sequential photo ioniza-
tionflame ionization detectors. Just before the
(Aq-NaHSO4-HS)
We placed 10 mL of Type 1 water and 0.25 g of
VOA vials (22 mL) were transferred to the auto
NaHSO4 into auto sampler VOA vials, then intro-
sampler system, each was shaken for approximately
duced ampoules. Once the vials were sealed, the
2 minutes. Vial pressurization settings of 7 and 10
lb/in.2 (48 and 69 kPa) were used, respectively, for
ampoules were broken and their contents com-
the 25 and 85C equilibration temperature settings.
pletely dispersed. Samples were analyzed 2 days
after dispersionextraction when prepared by
For each sample preparation procedure, ana-
aqueous treatment, and within 2 hours when
lyte concentrations were established relative to HS
vapor-fortified. Before HS vapors were removed,
standards prepared by adding small (microliter)
the VOA vial was held for 20 minutes at 25C.
quantities of a MeOH stock solution to auto sam-
pler vials containing the same solution composi-
MeOH extraction
tion and volume as the samples (e.g., 10 mL of Type
HPLC grade MeOH was transferred to VOA vi-
1 water and 0.100 mL of solvent or appropriate
als and an ampoule was placed in each. A 10-mL
saltacid). However, since the 2 g of soil and the
volume was used for the aqueous treatment and 5
broken glass ampoules were present for the three
mL was used for vapor-fortified soils. After we
equilibrium methods, these samples contained an
capped the vials, the ampoules were broken, and
additional phase and had a reduced HS volume
the soil was completely dispersed by hand shak-
(i.e., the glass ampoule and soil occupied approx-
4
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