Introduction to Electrochemistry and Electroanalysis with Carbon Paste–Based Electrodes - Electroanalysis with Carbon Paste Electrodes - page 5

to. the. world. of. carbon. pastes. in. his. classical. contribution. to. the. reaction. kinetics. of. CPEs. [68],.
.having.achieved.a.remarkable.citation.index.and.competing,.in.this.respect,.with.the.introductory.
report.itself.(see.[7].and.data.analysis.therein).
1.1.7 1988-1995: W orldWide s pread oF C arbon p asTes
WiTh e nzyMes as a n oVel T ype oF b iosensor
Hand.in.hand.with.the.development.of.CMCPEs.[69],.carbon.pastes.were.also.examined.as.a.
substrate.for.incorporating.biological.modiiers—enzymes,.co-enzymes,.or.suitable.tissues.con-
taining.such.natural.catalysts..Hitherto.the.most.comprehensive.review.on.CP-based.biosensors.
[70].quotes.that.the.earliest.examples.of.such.modiications.go.back.to.the.1980s.or.even.before,.
which.is.the.case.of.the.already.mentioned.electrode.[52].with.chemically.immobilized.species.
of.NAD + .(oxidized.form.of.NADH)..Similar.attempts.followed.soon,.where.enzyme(s).had.been.
anchored.onto.the.protective.membranes.of.carbon.paste-based.substrates.with.admixed.media-
tors.(see,.e.g.,.[71,72])..However,.the.direct.incorporation.of.enzyme.into.a.carbon.paste—i.e.,.
mechanical.modiication.without.any.other.linking.or.coating.elements—was.described.for.the.
irst.time.by.Matuszewski.and.Trojanowicz.[73]..Their.simple.sensing.device.for.amperometric.
detection.of.glucose.contained.the.paste.with.glucose.oxidase.embedded.inside.and.loaded.into.
a.small.well.at.the.bottom.of.a.common.electrode.shaft..Reportedly,.excellent.stability.of.such.a.
sensor.(min..3.weeks).together.with.surprisingly.rapid.response.due.to.the.functioning.of.carbon.
paste.as.arrays.of.miniature.membranes.[69,70].seems.to.be.a.suficiently.stimulating.factor.that.
had.initiated.a.real.boom.in.the.development.and.subsequent.applications.of.biologically.modi-
ied.carbon.paste.electrodes,.commonly.known.as.CP-biosensors.
Thus,.this.type.of.biosensors.came.rapidly.to.the.fore,.forming.in.a.short.time.another.major.area.
within.the.electrochemistry.with.CPEs..Again,.one.of.the.reasons.for.this.widespread.use.was.the.
uniqueness.of.carbon.paste.materials.in.their.lexibility.to.be.modiied..Similarly.as.with.CMCPEs,.
carbon.paste-based.biosensors.offer.a.wider.choice.in.modiication.strategies.than.those.available.
for. common. solid. electrode. materials.. Among. others,. the. substrates. from. heterogeneous. carbon.
pastes.allow.one.to.incorporate.an.enzyme.and.a.mediator.in.one.matrix,.which.improves.the.kinet-
ics.of.the.corresponding.enzymatic.reaction.and.fastens.the.biosensor.response..Also,.carbon.pastes.
can.be.simply.modiied.with.two.different.enzymes.forming.bifunctional.(dual).biosensors.and.may.
contain.suitable.stabilizing.additives.as.well.as.some.biological.tissues.or.microbial.cells.(particu-
lar.examples.and.further.details.are.given.in.Chapter.5)..These.carbon.paste-based.dual.sensors.
were.one.of.the.models.for.the.future.constructions.of.multifunctional.sensors.known.as.electronic.
tongues.(see.the.following).
It.can.be.concluded.that.biologically.modiied.carbon.pastes.had.been.in.a.lead.position.through-
out.the.1990s,.holding.the.same.position.up.to.the.mid-2000s,.when.laboratory-made.carbon.paste.
material. stepped. into. an. uneven. confrontation. with. commercially. marketed. carbon. inks. as. sub-
strates.for.serial.machining.or.manufacturing.of.screen-printed.(carbon).electrodes,.SP(C)Es.[74]..
This.hypothetical.battle.had.its.beginnings.in.the.mid-1990s.[75],.thus.characterizing.the.upcoming.
period.of.our.chronicle.
1.1.8 1996-2000: s TarTing C oMpeTiTion oF T radiTional C arbon p asTes
WiTh s Creen -p rinTed s ensors and o Ther C arbon C oMposiTes
Probably.the.irst.analysis.devoted.to.this.competition.was.included.in.the.review.[75].introduced.
earlier,.positioning.CPEs.in.the.role.of.laboratory.predecessors.of.SP(C)Es..Because.the.respective.
literature. source. is. not. so. easily. accessible,. the. entire. rather. visionary. discussion. can. be. briely.
presented.herein—through.interpretation.of.carbon.pastes.and.carbon.inks.as.the.electrode.mate-
rial.close.in.nature..Both.are.heterogeneous.substrates.and.both.can.be.classiied.as.dispersions.of.