Chemistry Reference
In-Depth Information
The.whole.assay,.where.OxP.means.an.oxidation.product.of.the.original.pharmaceutical.resulted.in.
highly.selective.procedure.for.practical.determination.of.Clp.([226].with.a.certain.tolerance.to.the.
precision.due.to.slight.losses.of.Clp.in.the.removed.CP-layer..Nearly.the.same.result.was.achieved.
in.an.alternate.procedure,.when.both.UA.and.Clp.had.been.left.to.be.accumulated.together.and,.
without.any.surface.renewal,.the.corresponding.(and.almost.merged).response.was.registered.
In. the. second. step,. the. CP-surface. was. carefully. removed. and. the. measurement. repeated..
Thus,.solely.Clp.as.the.compound.entrapped.in.the.carbon.paste.bulk.might.give.the.respective.
signal.and.the.difference.of.both.responses.from.the.experiments.No.1.and.No.2.led.to.the.desired.
separation:
.
1..
Accumulation
(
Clp
)
+
(
UA
)
→
(
Clp
)
+
(
UA
)
(8.7)
-
SOLN
SOLN
CP SURF
-
CP
BULK
.
.
.
2..
Voltammetric scan No 1
(
Clp
)
+
(
UA
)
→
(
Clp UA
+
)
(8.8)
.
CP BULK
-
CP SURF
-
.
.
3..
Surface removal and voltammetric scan No 2
:
(8.9a)
(
Clp
)
+
(
UA
)
→
(
Clp
)
.
CP BULK
-
CP SURF
-
.
(
Clp UA
+
)
−
(
Clp
)
→
(
UA
)*
(8.9b)
.
.
where.(UA)*.is.the.differentiated.signal.(or.concentration,.resp.).for.interfering.species.UA.
Although. both.approaches. described. may. lead.to. somewhat. different.results,. all.these. experi-
ments.have.clearly.demonstrated.a.speciic.feature.of.CPEs—their.operability.(or.functioning).by.
means.of.electrochemically.active.bulk.
Last.but.not.least,.some.contemporary.reviews.on.electroanalysis.of.pharmaceuticals.should.also.
be.mentioned.[187,2183,2639-2641],.including.a.report.devoted.to.the.CPEs.themselves.[158],.all.
being.recommended.as.the.primary.source.of.expertise.information.
8.4 DETERMINATION OF BIOLOGICALLY IMPORTANT COMPOUNDS
The.last.large.group.of.the.analytes.in.electroanalysis.with.CPEs,.CMCPEs,.and.CP-biosensors.is.
gathered.in.the.following.sections,.in.Tables.8.15.through.8.28,.including.those.cited.in.the.previous.
text.and.via.a.long.string.of.new.references.[2642-3269].
BICs. have. long. been. the. center. of. interest. in. analytical. chemistry. and. biochemistry,. either.
to.monitor.biochemical.pathways.or.to.detect.the.fate.of.exogenic.or.endogenic.compounds.and.
toxins..After.the.construction.of.the.irst.(electro)chemical.sensor.by.Cremer—who.was,.in.fact,.
biologist—and.its.description.by.Haber.and.Klemensiewicz.[3256,3257],.it.took.roughly.half.a.
century.until.the.irst.biosensor.for.glucose.was.invented.by.L..Clarke,.earning.thus.the.merit.of.
being.the.“father.of.biosensors”.[1908]..First.commercialization.of.amperometric.glucose.biosen-
sors.started.in.the.early.1970s.by.
Yellow Springs Instruments
..In.fact,.the.real.breakthrough.was.
achieved.in.1987.by.
MediSense
.when.launching.screen-printed.electrodes.as.glucose.biosensors.
for. medical. application.. Yet. before,. Guilbault. was. the. irst. to. use. a. puriied. enzyme. (urease).
to. construct. a. potentiometric. biosensor. [3261],. Palecek. started. with. electrochemistry. of. DNA.
in. 1958. [3028,3258,3259],. and. Janata. must. be. accredited. with. describing. the. irst. immunosen-
sor.[3260]..These.are.just.some.milestones.in.the.history.of.the.electrochemistry.of.BIC.and.of.
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