Chemistry Reference
In-Depth Information
admixed.in”.could.later.be.adapted.for.studying.inorganic.solids,.the.pioneering.studies.by.Kuwana.
et.al..are.often.regarded.to.be.the.initial.step.in.the.development.of.the.so-called.carbon.paste.elec-
troactive.electrodes.(CPEEs).that.are.discussed.separately,.in.Section.7.2.
A.similar.reason—i.e.,.combination.of.CPEs.with.measurements.in.organic.solvents—was.also.
behind.the.second.key.work.[16].that.introduced.a.new.type.of.CPE.containing.up.to.50%.(w/w).of.
solid.surfactant.dissolved.in.the.binder,.acting.as.the.stabilizer.against.disintegration.of.the.native.
paste.in.nonaqueous.solutions.of.a.majority.of.organic.solvents.(e.g.,.MeOH,.EtOH,.ACN,.DMSO,.
or.DMFA)..In.this.case,.one.can.also.refer.to.the.purposely.performed.change.in.the.typical.proper-
ties.of.carbon.paste.mixtures.in.an.effort.to.improve.their.resistivity.in.aggressive.conditions..In.
other.words.and.generally,.this.study.was.the.irst.actual.modiication.of.carbon.pastes,.leading.to.
the.desired.behavior.of.a.particular.CPE.for.a.given.application.
1.1.4 1965-1975: e
xpansion
oF
C
arbon
p
asTe
e
leCTrodes
in
e
leCTroCheMiCal
l
aboraTories
Whereas.the.activities.of.Adams's.school.had.continued.(see,.e.g.,.[17-25]),.representing—with.a.
few. exceptions. [26,27]—the. research. activities. in. Northern. America,. electrochemists. and. elec-
troanalysts. in. the. Old. Continent. came. rapidly. to. the. fore. [28-40].. In. the. late. 1960s,. especially,.
researchers. from. the. Central. Europe. were. active. in. developing. and. characterizing. various. types.
of.CPEs.[28-32],.including.newly.proposed.mixtures.with.silicon.polymer-based.binders.such.as.
highly.viscous.oils.and.greases.[28].or.even.rubber.[32]..(The.latter.was.apparently.the.irst.example.
of.the.“solid-like”.CPE.whose.originally.soft.consistency.had.been.turned.to.a.compact.composite.
by.solidifying.the.binder,.here,.by.cold.vulcanization.).Within.these.studies,.some.innovative.con-
structions.of.carbon.paste.holders.were.designed.[28,31],.featuring.also.an.unusual.device.for.renew-
ing.the.carbon.paste.surface.with.the.aid.of.a.stretched.piano.string.[33].or.new.illing.procedures.
[34]..Finally,.there.were.some.pioneering.reports.on.the.use.of.a.CPE.in.equilibrium.potentiometry.
[35,36],.in.analysis.of.biologically.important.compounds.[37],.or.in.voltammetry.of.solids.[38].
The. 1970s. brought. several. valuable. contributions. into. the. advanced. characterization. of. CPEs.
[39-41],.including.a.sophisticated.procedure.for.protecting.the.graphite.particles.against.sorption.of.
air.oxygen.[39],.which.had.attracted.the.carbon.paste.inventor.himself.[3]..The.same.time.period.
saw.also.the.decline.of.Adams's.dominance.in.the.ield.[42-44],.more.speciically,.his.reorientation.
toward.pharmaceutical.and.biological.sciences—pharmacotoxicology.and.
in vivo
.monitoring.[45-50]..
(The.last.contribution.is.a.review,.cementing.Adams's.position.within.the.clinical.research—namely,.
in.contemporary.brain.electrochemistry—and.it.has.also.commented.in.detail.on.the.irst.successful.
assays.with.carbon.paste-based.microelectrodes.implanted.in.living.laboratory.animals.)
1.1.5 1976-1980: p
ioneering
C
heMiCal
M
odiFiCaTions
oF
C
arbon
p
asTe
The.late.1970s.showing.some.stagnation.in.publication.activities.(see.Figure.1.1).had.spawned.two.
studies.whose.signiicance.was.soon.recognized.as.a.breakthrough.in.the.ield..At.irst,.Cheek.and.
Nelson.([51];.the.second.author.being.further.absolvent.of.Adams's.school.[4]).reported.on.an.inten-
tionally.made.modiication.with.amino.groups.chemically.immobilized.onto.the.graphite.particles.
by.means.of.rather.complicated.laboratory.procedure..However,.the.effort.made.had.been.compen-
sated.by.the.result,.and.the.sensor.was.found.to.exhibit.a.high.afinity.to.Ag(I).ions,.enabling.their.
determination.far.below.the.sub-nanomolar.level..The.second.milestone.happened.in.Japan,.where.
Yao.and.Musha.[52].introduced.the.irst.prototype.of.a.carbon.paste.biosensor,.although,.accord-
ing.to.the.authors.themselves,.the.respective.coniguration.was.a.chemically.modiied.CPE.applied.
to.the.determination.of.a.biologically.important.compound..Apart.from.the.proper.classiication,.
both.reports.predetermined.the.turbulent.movement.in.the.subsequent.decades.signaling.two.domi-
nant.areas:.(i).chemically.modiied.CPEs.and.(ii).biologically.modiied.CPEs.(carbon.paste-based.
biosensors).
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