METHYLENE CHLORIDEanalysis文档格式.docx

METHYLENE CHLORIDEanalysis文档格式.docx

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Recommendedairvolume

andsamplingrate:

3Lat0.05L/min

Reliablequantitationlimit:

0.201ppm（0.697mg/m3）

Standarderrorsofestimate

atthetargetconcentration:

（Section4.7.）

5.8%（10ppm）

6.5%（500ppm）

Statusofmethod:

Evaluatedmethod.ThismethodhasbeensubjectedtotheestablishedevaluationproceduresoftheOrganicMethodsEvaluationBranch.

Date:

February1990

Chemist:

DonaldBurright

OrganicMethodsEvaluationBranch

OSHAAnalyticalLaboratory

SaltLakeCity,Utah

1.GeneralDiscussion

1.1.Background

1.1.1.History

Thisprocedureallowstheuseofasinglestandardsize（6-mmo.d.?

4-mmi.d.?

7cm）adsorbenttubeforthecollectionofmethylenechloride.Becausemethylenechloridereadilymigratesoncharcoal,earliermethodsrequiredtheuseoftwostandardsizecharcoaltubesconnectedinseries,whichcouldbeisolatedfromeachotheraftersampling,（Ref.5.1.）ortheuseofacustomdesignedjumbosizeadsorbenttubecontaininganinconvenientlylargeamountofcharcoal（Ref.5.2.）.Thesetwoproceduresovercometheeffectsofmigrationbyeitherisolatingthebackupsectionfromthesamplingsectionsothatitwouldnotbecontaminatedbythemigratingmethylenechlorideorbyusingsuchalargequantityofcharcoalthatmigrationisslowedtoanacceptablerate.Thebenefitofasinglestandardsizeadsorbenttubeismadepossiblebytheuseofanadsorbentmaterial,CarbosieveS-III,whichdemonstratesnegligiblemethylenechloridemigration.CarbosieveS-III,availablethroughSupelco,Inc.,isasphericalcarbonmolecularsieveandhasasurfaceareaofabout800m2/g,aboutthesameascharcoal.

ThisevaluationwasperformedattwotargetconcentrationsbecausethecurrentOSHAPELformethylenechlorideis500ppm（TC-500）andOSHAisnowintheprocessof6（b）rule-makingtoreducetheoccupationalexposuretomethylenechloride.Forthepurposeofthisevaluation,10ppmwasselectedasthelowertargetconcentration（TC-10）.AgoalofthisevaluationwastodevelopasamplingprocedurethatwillaccommodateboththecurrentPELandanewlowerlimitifoneispromulgated.ThecurrentACGIHTLVis50ppmandthecurrentNIOSHRELstatesthatexposuretomethylenechloridebecontrolledtothelowestfeasiblelevel.（Refs.5.3.-5.5.）

1.1.2.Toxiceffects（ThissectionisforinformationonlyandshouldnotbetakenasthebasisofOSHApolicy.）

Methylenechloridecanaffectthebodyifitisinhaled,swallowedorcomesincontactwiththeeyesorskin.Methylenechlorideisananestheticandinhalingthevapormaycausementalconfusion,light-headedness,nausea,vomiting,andheadache.Continuedexposuremaycauseincreasedlight-headedness,staggering,unconsciousness,anddeath.Highvaporconcentrationsmaycauseirritationoftheeyesandrespiratorytract.Exposuretotheliquidmaycauseirritationtotheskinandeyes.Extendedexposuretotheliquidbytheskinmaycauseskinburns.（Ref.5.6.）

Carbonmonoxideisametaboliteofmethylenechlorideinanimalsandhumans.NIOSHhasrecommendedthatifthecarbonmonoxideconcentrationisabove9ppm,eithertheconcentrationofmethylenechlorideorcarbonmonoxideshouldbereduced.（Ref.5.5.）

Onthebasisofcarcinogenicandtumorigenicresponsesinratsandmice,NIOSHrecommendsthatmethylenechlorideberegardedasapotentialoccupationalcarcinogen.（Ref.5.3.）

1.1.3.Workplaceexposure

Methylenechlorideisusedmainlyasasolventinpaintremovers,aerosolmixtures,chemicalreactionprocessesandasablowingagentforflexiblefoams.Photography,metal-work,refrigeration,chemicalprocessing,pharmaceutical,flexiblefoam,andfoodindustriesusemethylenechloride.（Ref.5.8.）Methylenechloridehasbeenusedtoextractheat-sensitivenaturallyoccurringsubstances,suchascocoa,ediblefats,spices,andbeerhops.Ithasalsobeenusedinthedecaffeinationofcoffee.（Ref.5.7.）

Approximately230millionkilogramsofmethylenechloridewereproducedintheUnitedStatesin1988.（Ref.5.9.）In1986,NIOSHestimatedthat1millionworkerswerepotentiallyexposedtomethylenechloride.（Ref.5.5.）

1.1.4.Physicalpropertiesandotherdescriptiveinformation（Ref.5.10.,unlessotherwisestated）

CASno.:

75-09-2

molecularweight:

84.93

molecularformula:

CH2Cl2

meltingpoint:

-97癈

boilingpoint:

39.8癈

vaporpressure:

53.3kPa（400mmHg）at24.1癈

vapordensity:

2.93（air=1）

specificgravity:

1.3266（water=1）

explosivelimit:

12%（lower）

19%（upper）（Ref.5.11.）

self-ignitiontemperature:

640癈（Ref.5.11.）

odor:

penetratingether-like

odorthreshold:

205-307ppm

appearance:

colorlessliquid

solubility:

1-2g/100mLofwater;

solubleinmostcommonorganicliquids

synonyms:

dichloromethane;

AerotheneMM;

methylenedichloride;

Narkotil;

R30;

Solaesthin;

Solmethine;

DCM;

methanedichloride;

methylenebichloride;

NCI-C50102;

UN1593（Ref.5.11.）

Theanalyteairconcentrationsthroughoutthismethodarebasedontherecommendedsamplingandanalyticalparameters.Airconcentrationslistedinppmarereferencedto25癈and101.3kPa（760mmHg）.

1.2.Limitdefiningparameters

1.2.1.Detectionlimitoftheanalyticalprocedure

Thedetectionlimitoftheanalyticalprocedureis0.0746ngperinjection（1.0-µ

Linjectionwitha28:

1split）.Thisistheamountofanalytethatwillgiveapeakwhoseheightisapproximately5timestheheightofthebaselinenoise.（Section4.1.）

1.2.2.Detectionlimitoftheoverallprocedure

Thedetectionlimitoftheoverallprocedureis2.09µ

gpersample（0.201ppmor0.697mg/m3）.Thisistheamountofanalytespikedonthesamplingdevicethatallowsrecoveryofanamountofanalyteequivalenttothedetectionlimitoftheanalyticalprocedure.（Section4.2.）

1.2.3.Reliablequantitationlimit

Thereliablequantitationlimitis2.09µ

gpersample（0.201ppmor0.697mg/m3）.Thisisthesmallestamountofanalytespikedonthesamplingdevicethatcanbequantitatedwithintherequirementsofarecoveryofatleast75%andaprecision（?

.96SD）of?

5%orbetter.（Section4.3.）

Thereliablequantitationlimitanddetectionlimitsreportedinthemethodarebaseduponoptimizationoftheinstrumentforthesmallestpossibleamountofanalyte.Whenthetargetconcentrationofanalyteisexceptionallyhigherthantheselimits,theymaynotbeattainableattheroutineoperatingparameters.

1.2.4.Instrumentresponsetotheanalyte

Theinstrumentresponseovertheconcentrationrangeof0.5to2timestheTC-10andTC-500targetconcentrationsislinear.（Section4.4.）

1.2.5.Recovery

Therecoveryofmethylenechloridefromsamplesusedin17-daystoragetestsremainedabove99.6%and97.3%attheTC-10andTC-500levels,respectively,whenthesampleswerestoredatabout22癈.Therecoveryofanalytefromthecollectionmediumduringstoragemustbe75%orgreater.（Section4.5.,regressionlinesofFigures4.5.1.1.and4.5.2.1.）

1.2.6.Precision（analyticalprocedureonly）

Thepooledcoefficientsofvariationobtainedfromreplicatedeterminationsofanalyticalstandardsat0.5,1and2timesthetargetconcentrationsare0.0330and0.0267attheTC-10andTC-500levelsrespectively.（Section4.6.）

1.2.7.Precision（overallprocedure）

Theprecisionsatthe95%confidencelevelforthe17-dayambienttemperaturestoragetestsare?

1.3%and?

2.7%attheTC-10andTC-500levelsrespectively.（Section4.7.）Theseeachincludeanadditional?

%forpumperror.Theoverallproceduremustprovideresultsatthetargetconcentrationthatare?

5%orbetteratthe95%confidencelevel.

1.2.8.Reproducibility

Sixsamples（TC-10）collectedfromacontrolledtestatmosphereandadraftcopyofthisprocedureweregiventoachemistunassociatedwiththisevaluation.Thesampleswereanalyzedafter11daysofrefrigeratedstorage.NoindividualsampleresultdeviatedfromitstheoreticalvaluebymorethantheprecisionreportedinSection1.2.7.（Section4.8.）

1.3.Advantages

BecausemethylenechloridedoesnotreadilymigrateonCarbosieveS-III,asinglestandardsizeCarbosieveS-IIIsamplingtubemaybeused.Thisisnotpermissiblewithactivatedcharcoalduetothemigrationofmethylenechloridefromthefrontsectiontothebacksection.

1.4.Disadvantages

1.4.1.ThefinemeshsizeofCarbosieveS-III（60/80）resultsinagreaterpressuredropacrossthesampletubethanoccurswiththeconventionalcoconutshellcharcoalsamplingtube.Thisresultsintheneedforthe0.05L/minsamplingrate.

1.4.2.Therecommendedsamplesizeis3Lasopposedtothe10Lsamplesizeofpreviousmethods.

2.SamplingProcedure

2.1.Apparatus

2.1.1.Samplesarecollectedusingapersonalsamplingpumpcalibratedtowithin?

%oftherecommendedflowratewiththesamplingdeviceattached.

2.1.2.Samplesarecollectedwith4-mmi.d.?

6-mmo.d.?

70mmglasssamplingtubespackedwithtwosectionsof60/80meshCarbosieveS-III.Thefrontsectioncontains130mgandthebacksectioncontains65mgofadsorbent.Thesectionsareheldinplacewithglasswoolplugs.Forthisevaluation,Supelco'

sORBO-91CarbosieveS-IIItubes（catalogno.2-0360）wereused.

2.2.Reagents

Nosamplingreagentsarerequired.

2.3.Technique

2.3.1.Im