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2007 vol. 3
Sample Preparation
References
1
Method for the Determination of Extractable Petroleum Hydrocarbons (EPH)
. Massachusetts Department of
Environmental Protection, Division of Environmental Analysis, Office of Research and Standards, Bureau of
Waste Site Cleanup, Revision 1.1, May 2004.
Table I
Excess moisture and improper storage compromise results by causing breakthrough into the aromatic fraction.
Table II
Restek Massachusetts EPH SPE tubes provide more accurate and reproducible results for critical marker compounds.
-------------- Restek --------------
-------------- Vendor A --------------
-------------- Vendor B --------------
-------------- Vendor C --------------
percent
n=3
percent
n=3
percent
n=3
percent
n=3
Analyte
r covery STD
RSD
r covery
STD
RSD
r covery
STD
RSD
r covery
STD
RSD
naphthalene
103.1
7.5
7.2
101.2
10.1
10.0
88.8
2.8
3.1
66.5
2.6
3.9
2-fluorobiphenyl
97.8
6.6
6.7
100.4
13.7
13.6
99.3
5.0
5.0
104.2
6.6
6.4
2-bromonaphthalene 98.6
5.3
5.4
71
7.1
10.0
50.0
8.1
16.1
29.2
1.9
6.6
Method Specific SPE Cartridges:
Massachusetts EPH
Rtx
®
-5 Columns (fused silica)
(Crossbond
®
5% diphenyl/95% dimethyl polysiloxane)
ID df (µm)
temp. limits
length cat. #
price
0.32mm 0.25 -60 to 330/350°C 30-Meter 10224
$450
PAHs:
acenaphthene
acenaphthylene
anthracene
benzo(a)anthracene
benzo(a)pyrene
benzo(b)fluoranthene
benzo(k)fluoranthene
benzo(ghi)perylene
chrysene
dibenzo(a,h)anthracene
fluoranthene
fluorene
indeno(1,2,3-cd)pyrene
2-methylnaphthalene
naphthalene
phenanthrene
pyrene
Hydrocarbons:
n
-nonane (C9)
n
-decane (C10)
n
-dodecane (C12)
n
-tetradecane (C14)
n
-hexadecane (C16)
n
-octadecane (C18)
n
-nonadecane (C19)
n
-eicosane (C20)
n
-docosane (C22)
n
-tetracosane (C24)
n
-hexacosane (C26)
n
-octacosane (C28)
n
-triacontane (C30)
n
-hexatriacontane (C36)
MA Fractionation Check Mix
(31 components)
25µg/mL each in hexane, 1mL/ampul
cat. # 31481
(ea.) $46
2-bromonaphthalene
2-fluorobiphenyl
MA Fractionation Surrogate Spike Mix
4,000µg/mL each in hexane, 1mL/ampul
cat. # 31480
(ea.) $28
1-chlorooctadecane
o
-terphenyl
MA EPH Surrogate Spike Mix
4,000µg/mL each in acetone, 1mL/ampul
cat. # 31479
(ea.) $28
Splitless Liners for PerkinElmer GCs
ID* x OD & Length (mm)
qty.
cat.#
price
Coextractables are another major concern with commercial cartridges. The
contaminants may be found in the packaging, cartridge materials such as the
SPE tube and frits, and the silica itself. The solvent blank extractions shown in
Figure 1 were collected from cartridges that were not pre-conditioned. Restek
cartridges show the lowest level of background peak area counts, indicating
the lowest level of background extractables.
When cartridges start out with low levels of extractables, it may not be neces-
sary to use the methylene chloride pre-treatment allowed in the method. This
pre-treatment can easily compromise the fractionation performance of the
cartridge beds and should be avoided whenever possible. In addition, fewer
product-related contaminants will provide clearer quantitation and require
fewer manual reviews of the data generated from the final chromatograms.
In all of the key performance areas, the Restek Massachusetts EPH SPE tubes
outperformed other commercially available products. Our cartridges are
designed to deliver accurate, reliable, and reproducible results. For high quality
separation products developed to prevent breakthrough and minimize back-
ground, reach for Restek sample preparation products.
% Breakthrough into Hexane (Aliphatic) Fraction
Analyte
Package intact,
no added moisture
200
µ
L water added
Package opened, resealed,
stored on shelf, 1 year
Package intact,
stored on shelf, 1 year
Naphthalene
0.0
0.0
----
----
2-fluorobiphenyl (surrogate)
0.0
0.0
----
----
2-bromonaphthalene (surrogate)
0.0
4.4
33.3
28.5
All tubes were 20 or 25mL with approximately 5g silica packing. Conditioning: 15mL hexane. Sample: 0.5mL of each fractionation check standard and surrogate standard. Elution
for fraction #1 (aliphatics): 17-20mL hexane (volume was optimized for each supplier and lot of tubes). Elution for fraction #2 (aromatics): 20mL of CH
2
Cl
2
. Each fraction was
dried to a total volume of 1mL and analyzed by GC.
1
Tube Volume, Bed Weight
qty.
cat.#
price
20mL, 5g
20-pk.
26065
$110
for
more
info
For more information on our selection of SPE tubes, visit us online at
www.restek.com