Table 1. Volatile organic compounds and petroleum products studied
during holding time and chemical preservation experiments.
o/w†
Vol.††
Solubility
(L)
Abbrev.*
(mg/L)
Log P
CAS
Set 1
Benzene
Ben
1780
2.13
5.7
71-43-2
Toluene
Tol
515
2.65
5.8
108-88-3
Ethylbenzene
E-Ben
152
3.13
5.8
100-41-4
p-Xylene
p-Xyl
200
3.18
5.8
106-42-34
o-Xylene
o-Xyl
152
2.95
5.7
95-47-6
trans-1,2-Dichloroethene
TDCE
600
2.09
3.5
156-60-5
Trichloroethene
TCE
1100
2.53
3.7
79-01-6
Tetrachloroethene
PCE
150
2.60
3.1
127-18-4
Set 2
m-Xylene
m-Xyl
173
3.20
5.8
108-38-3
Methylene chloride
MC
20,000
1.30
3.8
75-09-2
1,1-Dichloroethane
1,1 DCA
5500
1.78
4.1
75-34-3
Chloroform
CF
8000
1.97
3.4
67-66-3
1,2-Dichloroethane
1,2 DCA
8690
1.48
4.0
107-06-2
Bromodichloromethane
BDCM
4500
1.88
2.5
75-27-4
1,1,2-Trichloroethane
1,1,2 TCA
4500
2.18
3.5
79-00-5
Chlorobenzene
CB
500
2.84
4.5
108-90-7
Set 3:
Styrene
Styrene
300
2.95
5.5
100-42-5
Isopropylbenzene
iso-PB
50
3.66
5.8
98-82-8
n-Propybenzene
n-PB
55
3.57
5.8
103-65-1
n-Butyl benzene
n-BB
11.8
4.29
5.7
104-51-8
Carbon tetrachloride
C-tet
800
2.83
3.1
56-23-5
1,3-Dichlorobenzene
1,3 DCB
69
3.38
3.9
541-73-1
cis-1,2-Dichloroethene
CDCE
?
?
3.9
?
1,2-Dichloropropane
1,2 DCP
2700
2.28
4.3
78-87-5
Set 4:
Gasoline
Gas
95
* Abbreviation.
† Octanolwater partition coefficient.
†† Volume.
experiment. It was airdried for 24 hours, reduc-
neat (reagent grade) VOCs or unleaded gasoline
ing the moisture content (weight percent relative
to a 100-mL volumetric flask containing about
to dried soil) from 24 to 4.3% (ASTM D2216-66)
102 mL of groundwater. The quantities of the neat
passed through a 30-mesh sieve, and thoroughly
analytes added would have created an aqueous
mixed. The organic carbon content was 0.940.04%
concentration of approximately 50 mg/L, if dis-
(Hach method 8097). Subsamples of 1.000.01 g
solution were complete. However, this is unlikely
were transferred to 2-mL glass ampoules (Whea-
based on their solubilities. After adding either
ton, actual vol. ≈ 3.1 mL) some of which already
eight analytes or gasoline, the solution was man-
contained 0.25 g of NaHSO4 as a chemical preser-
ually shaken; then a Teflon stirring bar was intro-
vative (Table 2). Sodium bisulfate has a pKa of
duced and the flask topped off with water, leav-
1.92, and the quantity used created a pH of about
ing less than 0.5 mL of headspace. These solutions
1.9, once sufficient water was added to produce a
were stirred for at least 24 hours and then al-
slurry condition. For the series of experiments
lowed to sit undisturbed for 1 hour prior to re-
described here, 15 ampoules contained both NaH-
moving aliquots.
Each soil sample was spiked with a 200-L ali-
SO4 and moist soil, and 27 contained just moist
soil.
quot from the prepared aqueous solution by us-
ing a 500-L glass syringe (Hamilton). To avoid
The fortification solution was prepared by sep-
arately adding microliter volumes (Table 1) of eight
undissolved low density analytes that would ac-
2
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