Environmental Engineering Reference
In-Depth Information
would.be.expected.to.drive.the.development.and.standardization.of.environmental.
nanoparticle.analytical.methods.for.wider.application,.as.well.as.to.foster.competi-
tion. in. an. emerging. market. for. laboratory. services.. Instrumentation. and. stafing.
costs. will,. however,. remain. a. barrier. to. entry. into. the. ield. for. most. commercial.
laboratories.currently.offering.environmental.services.
. analYtiCal Methods
The.production.of.nanoparticle.materials.typically.requires.control.of.the.chemical.
composition,. size,. shape,. and. surface. characteristics. of. the. material.. Many. of. the.
analytical.techniques.applied.for.the.analysis.of.nanoparticles.during.development.
and.production.also.are.critical.to.laboratory.studies.of.fate.and.transport.and.expo-
sure.effects.to.ensure.that.the.material.being.tested.is.fully.understood..These.meth-
ods.also.may.be.components.of.analyses.to.detect.nanoparticles.after.their.release.
into.the.environment,.dispersion.in.air.or.water,.or.uptake.into.organisms.[1].
This. chapter. discusses. highlights. of. the. most. widely. used. techniques,. provid-
ing. the. basic. science. of. the. analyses. and. describing. the. type. of. information. that.
can.be.expected.and.reported.for.possible.environmental.applications..These.tech-
niques,.as.listed.in.Table.5.1,.represent.what.must.be.considered.initial.approaches.of.
researchers.to.address.environmental.issues;.it.is.likely.that.over.time,.other.current.
techniques.or.newly.developed.instrumentation.will.also.prove.useful..Representa-
tive. citations. are. provided. where. methods. have. proven. successful. for. analyses. of.
nanoparticles.present.in.air,.water,.or.soils..However,.it.should.be.noted.that.most.
environmental.analyses.reported.to.date.for.nanoparticles.have.focused.on.natural.
species. such. as. colloids. in. water. or. on. combustion-related. emissions.. Engineered.
nanoparticles.have.been.characterized.in.laboratory.studies.and.in.indoor.air.moni-
toring.programs,.but.only.limited.studies.designed.to.detect.their.releases.into.or.fate.
in.ambient.air,.surface.or.ground.waters,.or.soils.or.waste.have.been.reported.[2].
More.in-depth.discussions.of.the.theoretical.basis.for.each.measurement.tech-
nique,.speciics.for.instrument.design,.detection.options,.and.data.examples.can.be.
found.in.a.review.article.[3].that.discusses.more.than.30.measurement. techniques.
in. detail,. presenting. the. theory. and. advantages. and. limitations. to. each.. Labora-
tory. analyses,. real-time. methods,. and. portable. instrumentation. for. particulate.
characterization. from. mobile. source. emissions. are. reviewed. in. a. literature. survey.
for.the.California.Air.Research.Board.(ARB).[4]..Many.of.the.methods.discussed.
and.equipment.illustrated.are.also.potentially.applicable.to.measurement.of.nanopar-
ticles. from. other. sources. in. the. environment.. A. recent. U.S.. EPA. symposium. on.
nanoparticles. in. the. environment. discussed. the. challenges. involved,. and. also. pre-
sented.highlights.of.applicable.measurement.methods.[5].
5.1.1 n
anOpartiCle
i
maging
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iZe
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hape
,
and
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hemiCal
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OmpOsitiOn
... electron Microscopy
Electron.microscopy.is.comparable.to.light.microscopy,.except.that.a.beam.of.elec-
trons.rather.than.light.is.used.to.form.images..Electron.beams.have.a.much.shorter.
wavelength. than. light. and,. as. a. result,. they. can. provide. the. resolution. required. to.
