environmental
Applications
note
RestekCorporation • (800)356-1688 •
#59110
environmental
rates, which may be used with this material, allow rapid extrac-
tion of 1 to 4 liters of aqueous samples. The tubes have a low
background level, especially suitable for pesticides. The high
surface area provides maximum capacitywith aminimum of bed
weight, reducing the volume of solvent used during extraction.
These same characteristics make CarboPrep
™
SPE tubes an ex-
cellent choice for cleanup of solid waste samples.
References:
1. The8
th
Report onCarcinogens - 1998,USDept. ofHealth&HumanServices,
PublicHealthService,www.ehis.niehs.nih.gov.
2. Recognition andManagement of PesticidePoisonings,USEPA,www.epa.gov.
3. “TraceDeterminationof Phenols inNaturalWaters”,A.DiCorcia,A. Bellioni,
M. Madbouly, S. Marchese,
Journal of Chromatography A
, 1996, 733, 383-393.
4. “UltratraceDetermination of Atrazine and its SixMajor Degradation Products in
Water”,A.DiCorcia,C.Crescenzi,E.Guerriero,R.Samperi,
ES&T
,1997,31,
1658-1663.
5. “Development of aMultiresidueMethod forAnalyzing PesticideTraces inWater”,
C.Crescenzi,A.DiCorcia ,E.Guerriero,R.Samperi,
ES&T
, 1997,31, 479-488.
References not available fromRestek.
Table I
Recovery of Chlorinated Pesticides from Solvent Extracts
Using CarboPrep
™
90 SPE Cartridge
Analytes*
Percent
RSD
Recovery n=6
dibromochloropropane
84.7
11.4
hexachlorocyclopentadiene
100.4
9.9
2,4,5,6 tetrachloro
-m
-xylene (surrogate)
90.6
8.1
cis
-diallate
73.0
11.3
hexachlorobenzene
96.8
7.4
trans
-diallate
93.0
10.3
α
-BHC
93.7
9.7
γ
-BHC
97.7
8.7
β
-BHC
97.0
7.9
δ
-BHC
106.7
6.4
heptachlor
111.6
8.0
aldrin
97.3
8.6
isodrin
98.5
7.8
heptachlor epoxide
101.6
7.0
γ
-chlordane
91.2
11.3
α
-chlordane
96.1
7.4
endosulfan I
97.0
7.5
4,4' DDE
100.1
6.7
dieldrin
104.9
4.1
endrin/chlorobenzilate
121.9
6.3
4,4' DDD
107.8
2.9
endosulfan II
108.8
4.9
4,4' DDT
103.5
6.5
endrin aldehyde
110.0
2.8
endosulfan sulfate
102.7
6.5
methoxychlor
119.1
6.1
endrin ketone
101.0
3.3
decachlorobiphenyl (surrogate)
96.8
3.5
*Analytes spiked at 80-160ng/mL in hexane.
CarboPrep™ SPE Cleanup of Method 8081A Chlorinated Pesticides
Many chlorinated pesticides have been banned for use because
of their short- and long-term toxicity, carcinogenicity, and envi-
ronmental persistence
1
. An expanded list of these chemicals,
some of which are still actively applied in the field, has been
included in the updated US Environmental Protection Agency
(EPA) Method 8081A. Despite the fact that most of these chlori-
nated pesticides are now illegal to use, manufacture, and trans-
port in the US, organochlorines are the eighth most common
source of pesticide poisoning that results in reportable illness
2
.
Although most of these chlorinated pesticides, insecticides, and
herbicides have limited water solubility and mobility, they are
found to bioaccumulate and persist in the environment. There is
an ongoing risk for exposure from a number of sources, so it is
still essential to test soils, wastewater, and sediments for their
presence.
Many of the additional components included in the EPAMethod
8081A update are difficult to analyze by gas chromatography
(GC), especially the isomers of the carbamate herbicide diallate.
However, these have been shown to separatewell using the Rtx
®
-
CLPesticides and Rtx
®
-CLPesticides2 column pair. For more
details on EPAMethod 8081A analysis using these columns,
refer to Applications Note #59547.
Standard EPAmethods for preparation and analysis of pesticide-
containing hazardous wastes require initial liquid/liquid extrac-
tion with dichloromethane, gel permeation chromatography
(GPC) fractionation of higher molecular weight interferences,
and a final cleanup of polar contaminants with Florisil
®
columns
or solid phase extraction (SPE) tubes, before analysis with GC-
electron capture detection (ECD). Many labs have found that
these cleanup precautions are not adequate and still produce
high backgrounds in analytical samples, resulting in difficult
quantitation and frequent GC/detector maintenance. The addi-
tion of a CarboPrep™ SPE tube, after the Florisil
®
cleanup, will
remove additional mid- to non-polar contaminants without com-
promising the recovery of pesticides. Extracts will have lower
backgrounds, producing better chromatograms with fewer inter-
ferences and extending the lifetime of inlet sleeves, guard col-
umns, and reducing maintenance of sensitive ECD detectors.
Results in Table I below show that recovery levels are excellent
for this extended chlorinated pesticides list, when following the
method described in Figure 1.
CarboPrep
™
SPE tubes contain a nonporous, chromatographic
grade, graphitized carbon, optimized for cleanup and concen-
tration of environmental samples. Graphitized carbon has also
been shown to be effective in the concentration and extraction
of many environmentally significant analytes found in drinking
and waste water, such as phenols and triazine herbicides
3,4
. This
form of carbon has been useful in multi-residue fractionation of
base/neutral compounds from acidic pesticides
5
. The high flow
