RestekCorporation
(800) 356-1688
Environmental
Extraction of Paraquat&Diquat fromWaterUsing
Resprep
™
-C8–47ExtractionDisks
note
A
pplications
cat.#59563
EPAmethods are
available from the
NationalTechnical
InformationService:
703-487-4650
analyte.Adjust sample pH to10.5±0.2
with sodiumhydoxide solution (10%w/
v) or hydrochloric acid solution (10%v/
v). Proceedwith the extraction immedi-
ately following samplepH adjustment.
ApparatusAssembly
Assemble theDiskcover
™
-47mmappa-
ratus, using theTeflon
®
reservior.
Teflon
®
parts shouldbeused tomini-
mize the riskof interferences. If using a
glassware apparatus, silanizationof the
apparatusmayprovide improved recov-
eries. Place theResprep
™
-C8diskon
the filter support,with theWRINKLED
SIDEUP.
DiskConditioning
Add the following solvents to the disk
in the sequence indicated:
Apply lowvacuum (1-2 in.Hg, 3-7kPa)
immediatelyupon additionof the first
solvent and throughout the entire condi-
tioning sequence.Donot allow any air
topass through the diskor to reach the
top surfaceof thediskduring the condi-
tioningprocess.
Note:
It is preferable to add the next
solvent directly to a layer of the pre-
vious solvent on the disk rather than
to allow any air to contact the disk’s
surface.
1. Add10mLmethanol to the disk
and immediatelyapply lowvacuum
(1-2 in.Hg, 3-7kPa). Draw through
until the top surface of themethanol
is just above the surface of the disk.
2. Add two10mL aliquots of deion-
izedwater directly to the liquidon
the surface of the disk. Continue to
draw throughunder lowvacuumuntil
the top surface of thewater is just
SolutionPreparation
The following reagent solutions are
used in the extractionprocedure—
ConditioningSolutionA:
Dissolve0.500gmof cetyl trimethyl
ammoniumbromide and5mLof con-
centratedammoniumhydroxide in
500mLof deionizedwater anddilute
to1000mL in avolumetric flask.
ConditioningSolutionB:
Dissolve10.0gmof 1-hexanesulfonic
acid (sodium salt) and10mLof con-
centratedammoniumhydroxide in
250mLof deionizedwater anddilute
to500mL in avolumetric flask.
SodiumHydroxideSolution
(10%w/v):
Dissolve50gmof so-
diumhydroxide in400mLof deion-
izedwater anddilute to500mL in a
volumetric flask.
HydrochloricAcidSolution
(10%v/v):
Add50mLof concen-
tratedhydrochloric acid to400mLof
deionizedwater anddilute to500mL
in avolumetric flask.
DiskElutingSolution:
Add13.5mLof orthophosphoricacid
and10.3mLof diethylamine to
500mLof deionizedwater anddilute
to1000mL in avolumetric flask.
Ion-pairConcentrate:
Dissolve3.75gmof 1-hexanesulfonic
acid in15mLof disk eluting solution
anddilute to25mLwithdisk eluting
solution in avolumetric flask.
SampleTreatment
Allow a 250mLwater sample to equili-
brate to room temperature in a silanized
amber glass bottle (or an amber polyvi-
nyl chloridebottle). ForQA/QC
samples, spikewith100µg/Lof each
Please note:
Thismethod is based
on the sample extractionproce-
dure fromSection 11.3 of EPA
Method 549.1, but is not intended
to be a replacement or substitute
for the official EPAMethod 549.1
procedure. Please refer directly to
the publishedEPAmethod for
additional information for the
preparation of samples to be ana-
lyzed according toEPAMethod
549.1.
EPAmethods are available from
NTIS (National Technical Infor-
mation Service), U.S. Department
of Commerce, Springfield,VA
22161, phone: (703) 487-4650.
