_1_ . ENVIRONMENTAL ANALYSIS

ImprovedAnalysis andIdentification ..........of NitramineandNitroaromatic

Explosives

:_. Ground Water Flow Direction

Waters introduces anew method for the

preconcentrationand analysis of Introductionexplosives

As military basesthroughoutthe UnitedStates Watershas improvedtheoriginal methodin

and Europeare decommissionedand readied severalways:

for otheruses,siteson thesebasesthat are • Developeda solid phaseextraction

contaminatedneedto be remediated.A major cartridge, specificallyfor this application,

sourceof this pollution isthe prolonged produc- which enablessubpart per billion detectiontion, storageand testingof explosivesweaponry, limits.

Todefinethe extentof the contaminationproblem • Enhancedthechromatographicseparationand monitor theprogressof thecleanup,samples of Method 8330 analytes.are initially screenedon-site]'2or sentfor labora-

• Employedphotodiode array (PDA)detectiontory analysis.Theapproved Environmental

to automaticallyconfirmthe identityofProtectionAgency (EPA)procedurefor this class

of compoundsis SW846 Method 8330 s.This sampleanalytesthroughthe useof specialHPLC-basedmethoddescribesconditionsfor the algorithmsand library-matchingroutines.

detectionof ppb levelsof certainexplosivesresiduesin soil, sedimentand water matrices.

Inthis method,soil and sedimentsamplesare

extractedusingacetonitrilein an ultrasonicbath,

filtered and analyzed. Aqueoussamplesare

concentratedby a liquid-liquidsalting-outextrac-

tion procedure.

Waters

Solid PhaseExtractionfor LowerSolvent "

Consumptionand FasterSampleThroughput

Toimprove methodperformanceand reducethe New Manufacturing ProcessProducesLow UV

useof organic solvents,the EPAis actively investi- ExtractablesResinfar Improved Performance

gating the useof new analytical techniquessuch Waters hasdevelopeda processto producea

as solid phaseextraction(liquid-solidextraction) low extractablesresincalled Porapak®RDx,specifi-

to replace liquid-liquidextraction.Solid phase cally designedfor preconcentratingnitroaromatics

extraction(SPE)requireslessglassware,is more and nitraminesin water5'6.We offer this highly-

economicaland fasterthan conventionaltech- purified resin in a 0.5g, 6cc Sep-Pak®Vac

niques, cartridge ready for immediateuse.Waters manu-

Analytical proceduresfor the analysisof explo- facturesPorapakRDXcartridgesto exacting back-

sivesusingsolid phaseextractionhavebeen ground specificationsin our IS0-9002 certified

successfullyvalidated by theUnited StatesArmy manufacturingfacility. Thechromatogramshown

EnvironmentalCenter.Until now, labs had to buy in Figure 1 comparestheanalysisof a 1 ppb

thepolymeric resins,cleanthem,and then spiked reagentwater sampleconcentratedwith aassembletheir own SPEcartridges4. PorapakROXcartridge to thatof a reagentwater

methodblank.Theabsenceof interfering peaksisToeffectivelyanalyze explosivesin ground and

testimonyto the high purity of the PorapakRDXsurfacewaters down to the subppb level, the

cartridges.resinmustbe ultra-clean,therebyeliminating the

possibilityof UV absorbingextractableswhich ExcellentRecoveries

mayinterferewith theanalysis.Sincemostpoly- The speciallyprepared resin is highly selectiveformericpackingsare produced from low molecular nitroaromaticand nitraminecompounds,resultingweight organic monomers,any residualmonomer in recoveriesof greater than 90%. Recoverydata,

or otherpotentially interferingcompoundsmust in TableI on the following page, also demon-be removedbeforethe packing can be used in stratesthe high reproducibilityof this approach.cartridgesfor trace analysisapplications.

Figure 1:Column: Waters Nova-Pak®Cs, 3.9xl 50ram

Comparison of II L Mobi,e ph.... 82:18 water/isopropanol

a) reagent water 0.0020 - Flowrate: 1.0 mL/mJnInjectionvolume: 100 pL

blank and b) spiked -_ Temperature: 24"Creagent water, bothprepared using s- 0.0016 - _ Detection: UV@ 254 nm<.< c, Sample: 1ppb explosivesconcentrated40-fold on Porapak

Porapak RDX =E Ibx, in 60:40 water/acetonitrile

Sep-Pakcartridges. _ ooo12- _- < __@ Z Z _.

_z_ , _-__-

............... _,-._P!°_!_4_,0.0000 - _ _ w _ . . _ :- . _ blank a

..... :_ ' _s5 10 I5 20 25 30 5 40

Minutes

HMX 100.5 6.76 100.6 3.95

TNB 95.9 3.54 99_3

Table I: Recovery data from preconcentrating RDX 90.9 6.48 98.8 3.24500 mL of explosives standards in Milli-Q _ _._water at two concentrations on Porapak RDx DNB 99.5 3.22 99.2 _Sep-Pak Vac cartridges. The number of TNT 97.0 3.07 102.0 3.75

replicates = 7. TETRYL 89.0 6.44

NB 96.5 2.52 97.9 2.89

3,5-DNA 91.2 3.318 !ii_!!i: i_!_!i:i!!__

2,4-DNT 97.3 3.41 100.0 3.46

2,6-DNT 94.5 3_49

2-Am-DNT 92.4 5.25 98.1 3.72

4-Am-DNT 90.9 4.99 _=z_?_;_i:_i_i_!4-NT 89.5 4.32 100.5 3.72

2-NT 96.8 6.65

3-NT 90.6 3.92 97.2 2.80

Columns: Waters Nova-PakC8,3.9xl00mm and

Nova-PakCN HP, 3.9xl00mm, in series

Mobile phase: 82:18 water/isopropanolFlow rate: 1.0 mL/min

Figure 2: Alternate two column separation of o.oo2o Injecti.... I.... 100IJLTemperature: 25"Cexplosive analytes. _ _ Detection: UV@ 254 nm

0.0016 " _ Sample: 40 ppb explosivesstandards in

E _ 60:40 water/acetonitrile_i <C

Z0.0012" '-,

Z

_ i z _ I_ ,-, Z< z Z0.0008 "

O4 - E I--m < z, zo.ooo .

0.0000 - i , i i i

5 10 15 20 25

Minutes

ImprovedResolutionof Explosives

Waters took a results-orientedapproach to An alternativeseparationwas developed,as

improvingthe resolutionof explosives7'8. shownin Figure2 on the previouspage, using

In ProposedUpdate II of SW 8469, 2-Amino-4,6- Nova-Pak®C8and Nova-PakCN HPcartridgecolumnsin series.Thisuniqueapproach accom-dinitrotobene and 4-Amino-2,6-dinitrotolueneare

added to theoriginal twelvetarget analyteslisted plishestheobjective of removingHMX from the

in Method 8330, FinalUpdate I. Theyare degra- void volumeallowing it to be accuratelyquanti-fied while still resolvingall thetarget analytesin a

dation productsof 2,4,6-Trinitrotoluene(TNT).In

somecasesthey are presentin higher concentra- single run.

tion than TNT. Figure3 representstheanalysisof nitroaromatic

Theoptimizedchromatogramin Figure 1 shows and nitraminesin groundwater from a contami-

excelbnt resolutionof theanalyteswhich enables nated site,spikedat 50 ppb. Although thereis a

reliable quantitation.Watershas refined theEPA large interferenceat thebeginning and through

methodallowing all fourteenanalytesto be identi- muchof the chromatogramcausedby otherfled. ground water constituents,all target analytesare

easilydistinguishedand quantified. Thisdemon-Anotherconcernwith theoriginal method isthe stratesthedependability, sensitivity,and effi-

early elution of Octahydro-1,3,5,7-tetranitro- ciency of Waters improved HPLCmethodfor1,3,5,7-tetrazocine(HMX),the mostpolar of nitramine/nitroaromaticanalysis.theseexplosives.When analyzed by reversed-

phaseHPLC,HMXelutesso quickly thatanydisturbancesor interferencesnearthevoid volume

may preventreliabb quantitationof theHMX.

Columns: We_rs Nova-PakCs, 3.9xl 00 mm,

and Nova-PakCN HP,3.9xl 00 mm,in series0.006 I Mobile Phase: 82:18 water/isopropanoJ_ Flow rate: 0.7 mL/min

Figure 3: _ II Injecti.... I.... 100 pLChromatogramof - _ll _ Temperature:25°Cspiked ground water _ \n_ _ Detection: UV@ 254 nmE :: _ Sample: Diluted to 60:40 water/acetonitrilefrom a site at The _ o.oo4

NavalSurface _ _1__Warfare Centerin _ _ _ _

Crane, Indiana. _ o.oo2_<_ _ .

0000#; _'o _'_ 2'o _ 3'o

Minules

4

,AdvancedPhotodiodeArray Detectionfor EnhancedSensitivityandCompound Identification

In theEPAmethod,water or soil extractsare each peak. Thespectraof the peakscan be

analyzed mice by HPLC.Thefirstanalysisis extractedand compared to confirm peak purity

performedusingC_8reversed-phasechromatog- and matchedto a library for peak identification.

raphy. If the analysisresultsin a peakwith the Theadvanced opticsof Waters996 PDAdetector

sameretentiontime as an explosivestandard, it is providessensitivitypreviouslyfound only-in vari-

necessaryto rerunthe sampleusinga cyano able UV/VIS detectors.Only Waters 996 PDA

columnfor confirmation, detectorachievesgenuineoptical resolutionof

Developmentsin HPLCdetectortechnologymake 1.2nmfor greatestspectraldetail, enablingdiffer-

it possibleto provide extensiveinformationabout entiationof compoundswith similarspectra.This

the samplebeing analyzed. Theadvancedcapa- combinationof sensitivityand resolutionfacilitates

bilitiesof Waters 996 PhotodiodeArray (PDA) the automatedidentificationof eventrace levels

detectorallows confirmationof peak identity in of components.

a single run. Figure4 demonstratesone way the996 PDA

In theoriginal methodthe separationis monitored detectordisplaysdata - theSpectrumIndex Plot.

by a UVdetectorat a fixed wavelengthof In thisfigure the UV spectrum,over the prese-

254nm. The996 PDAdetectoroperatesover the lectedwavelength range, is displayed for each

range 190-800nm. Theactual range is chosenby chromatographicpeak. Thespectralprofile of

the useraccording to the requirementsof the eachpeak can be automaticallycompared, by

application. Simultaneousmonitoringof these Millennium®Soft,,vare,to spectrastoredin its

wavelengthsproducesa completespectrumfor library.

Figure4: This

produced withWaters 996 PDAdetector,shows theUV spectrumof eachpeak. In addition tousing the spectra toconfirm identity,spectra also indicatethe wavelengthof maximumabsorbanceforoptimal detectorsensitivity.

AdvancedMillennium®Software with In TableII, purityangles are compared to purity.

PhotodiodeArray Detectionfor Greater thresholdsandlibrary matchanglesareConfidencein CompoundConfirmationand Identification compared to library matchthresholds.When the

TheMillennium2010 ChromatographyManager purity thresholdvalue is higher than the purity

controlsthe entireHPLCsystem,processesdata angle, the peak is consideredpure. When thematchthresholdis higher than the matchangle,

and managesinformation.Thepower ofthe library matchis acceptedwith a high degree

Millenniumsoftware is unlikeany otheravailableof confidence.Coelutionof peaks,as is thecase

today. Millenniumsoftwarecomparesthe spec- with 2-NTand 4-NT,may resultin purity or matchtrumat the peakapex to all otherspectraat

each point along the peak. A special peak purity anglesgreater than the respectivethresholds.In

algorithm thenusesvectoranalysisto mathemati- thesecases,the degreeof confidencein peakidentification and quantitation is reduced.

cally consolidateall of thesecomparisonsand

determinepeak purity.After thepeak purity is

establisheda similar routinecomparesthe peak

spectrumto spectra in a library to locatea matchfor identification.Theresultsof thesevector

analysesare expressedas a purity angle or a

matchangle.

1 Match 1 Match 1

Table I1:Millennium (min) Angle Threshold Angle Threshold SpectralName Lib.Namepeak purity and

compound identifica- 1 2.217 0.906 1.657 0.425 1.250 HMX Explosivestion from an explo-

sives analysis. 2 3.483 0.329 1.434 _ 0.443 1.177 TNB Explosives3 4.283 0.895 2.017 0.426 1.525 RDX Explosives

4 6.767 0.303 1.367 0.170 1.236 DNB Explosives

5 7.267 0.676 1.598 0.208 1.323 TNT Ex_losives

6 8.617 0.517 1.768 0.506 1.407 Tetryl Ex_losives

7 10.150 0.466 1.397 0.280 1.218 NB Ex_losives

8 14.450 0.562 1.572 0.428 1.336 2,4-DNT Ex_losives

9 17.333 1.390 2.232 1.628 1.734 2,6-DNT Ex_losives

10 20.433 0.782 1.913 0.408 1.583 2-Arn-4,6-DNT Ex_losives

I 1 22.467 1.972 2.449 1.781 1.948 4-Am-2,6-DNT Ex_losives

12 23.883 0.536 1.338 1.422 1.296 4-NT Ex_losives

13 24.467 5.128 1.610 3.639 1.538 2-NT Ex_losives

14 27.333 0.547 1.820 0.914 1.594 3-NT Ex_losives

4

tedGe Star

Waters Discovery System is a fully integrated demanding environmental analyses. Everything

HPLCsystem featuring the 996 PDA detector you need to perform enhanced analyses is avail-

and is operated by the Millennium 2010 able from Waters--Porapak RDXSep-Pak

Chromatography Manager. Millennium also cartridges for the concentration, Nova-Pak C8

processes the data, manages the information and Nova-Pak CN HP columns for the separa-

and produces reports in standard and user- tion, and the Waters Discovery System for highly

defined formats. It incorporates a relational sensitive, dependable detection and identifica-

data base for tracking and trending results, tion of explosives.

The Discovery System performs enhanced

analysis and automated identification of

explosives as well as a broad range of other

Figure 5: WatersDiscovery Systemis available witha choice of highprecision solventdelivery systems,advanced autosam-pier, photodiodearray detection--allintegrated with theMillennium 2010ChromatographyManager.

,* b

References

1. T.F.Jenkinsand P.W.Schumacher,1990. Evaluationof a Field 6. M.P.Maskarinec_D.L.Manning,R.W.Harvey,W.H. Griest,Kitfor Detectionof TNTinWater andSoils.U.S.ArmyCRREL and B.A.Tomkins,1984. Determinationof MunitionsSpecialReport,90-20. ComponentsinWater by ResinAdsorptionandHighPerformance

2. M.E.Walshand T.F.Jenkins,1991. LiquidChromatographyElectrochemicalDetection.Developmentof a FieldScreeningMethodfor RDXinSoil. Journalof Chromatography.Vol. 302. Page51.U.S.Army CRRELSpecialReport91-7. 7. S. ©ehrleandE.S.P.Bouvier,May, 1994.Analysisof

Nitroaromaticand NitramineExplosivesin WaterUsingHPLCwith3. July,1992. U.S.EPATestMethodsfor EvaluatingSolidWaste.PhotodiodeArray(PDA)Detection.Presentedat HPLC'94,

Physical/ChemicalMethods.SW-846,3rd Edition,FinalUpdate 1.Minneapolis,MN.

4. M.G. Winslow,B.A.Weichertand R.D.Baker,July8-12, 1991.Determinationof Low-LevelExplosiveResiduesin Water by HPLC: 8. E.S.P.Bouvier,L.R.Steritiand S.Oehrle,June,1993.SolidPhaseExtractionvs.Salting-outSolventExtraction. PreconcentrationandAnalysisof NitroaromaticandNitramine _Proceedingsof theEPA7thAnnualWasteTestingand Qualily ExplosivesinWater.AssuranceSymposium,Washington,D.C. Presentedat NortheastACS23rd Meeting.Boston,MA.

9. November,1992. U.S.EPATestMethodsfor EvaluatingSolid5. D.H.Freeman,R.M.AngelesandI.C. Poinescu,1976.Waste.Physical/ChemicalMethods.High PerformanceLiquidChromatographicSeparation

of RDXand HMXExplosivesonAdsorptivePolymers. SW-846,3rd Edition,ProposedUpdateII.Journalof Chromatography.Vol. 118. Page157.

ii,,;{

_!i Waters

34 Maple StreetMilford, MA 01757 U.S.A.Tel.508-478-2000Within the U.S. 1-800-252-4752FAX508-872-1990

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