environmental
Applications
note
RestekCorporation • (800)356-1688 • (814)353-1300 •
#59565A
environmental
Extractionofpolynucleararomatichydrocarbons (PAHs)using
Resprep
™
-18-47SPEdisksandResprep
™
-6Dextractionsystem
SamplePretreatment
Allow1Lof deionizedwater toequilibrate to room temperature.
Adjust sample pH to less than 2with 6NHCl.Add 5mLof
methanol andmix thoroughly. ForQA/QC samples, spikewith
1mLof a2µg/mL solution for a final concentration in thewater
of2ppb.
ApparatusAssembly
Assemble theDiskcover
™
-47extractiondiskholderwith
reservoir,making sure theTeflon
®
o-ring is inplace. Alsobe
sure toplace theC18disk in theDiskcover
™
-47 extractiondisk
holder
wrinkled sideup
.Assemble theResprep
™
-6D extraction
systemasdetailed in its instruction sheet, alongwith thevacuum
pump, vacuum line, andvacuum trap.
DiskPrecleaning
Add10mLofmethylene chloride to the top surfaceof thedisk
and immediatelydraw it throughunder vacuum at 15 in.Hg.
Continue todrawvacuum at 15 in.Hg for 5minutes, removing
all solvent.
DiskConditioning
Add10mLofmethanol to the top surfaceof thedisk and let
stand for a fewminutes.Draw themethanol through thedisk
until themethanol’s top surface is just above thedisk.
Donot
allow any air topass through the disk or reach the top
surfaceof thedisk.
Note: It ispreferable to leaveextra liquid
above thedisk rather than allow any air to contact thedisk
surface.
SampleAddition
Pour the sample into theDiskcover
™
-47 reservoir, adding it
directly to the filmofmethanol left on thedisk from thecondi-
tioning step.Adjust thevacuum to approximately25 in.Hg.
DiskDrying
After the entire samplehas beenprocessed, draw air through the
diskunder vacuum to remove any residualwater from thedisk.
AnalyteElution
Release systemvacuum. Insert thecollection rackandvessels
into theglass chamber,making sure to label eachvesselwith the
correspondingDiskcover
™
-47. Reassemble theResprep
™
-6D
extraction system.Add5mLmethylenechloridedirectly to the
samplebottle, andgently swirl to rinseall inner surfacesof the
bottle.Transfer themethlyenechloride to thediskusingaglass
pipetteand rinse the reservoir sides in theprocess.Let the solvent
stand for threeminutes.Draw the solvent through thedisk at
5 in.Hg. Repeat thebottle rinse anddisk elutiononcemorewith
a freshaliquot ofmethlyenechloride, combiningall eluates in the
collection tube.
Resprep
™
samplepreparationproducts allow complete, clean
sample extraction formore accuratePAH analyses.
