Carbon Pastes and Carbon Paste Electrodes - Electroanalysis with Carbon Paste Electrodes - page 37

1

1

2

2

1

3

4

3

3

4

(A) (B) 4

1

1

2

2

3

3

R
D

4

5

(C) (D)

FIGURE 2.8 Basic.constructions.of.carbon.paste.holders..(A).Glass.and.plastic.tubes:.1,.tube.(syringe);.
2,.….piston,.3,.contact.(metal.wire);.and.4,.illing.of.carbon.paste.(CP)..(B).Adams's.construction:.1,.Cu-wire.
and.Pt-contact;.2,.glass.tube.(conically.narrowed);.3,.Telon ® .plug;.and.4,.well.illed.with.CP..(Newly.redrawn.
from.Adams,.R.N.,. Electrochemistry at Solid Electrodes ,.Marcel.Dekker,.New.York,.1969.).(C).Rotating.ring-
disc.CPE..1.and.2,.inner.and.outer.electrical.contact.and.3,.Telon.body.(“P”:.ring,.“D”:.disc)..(D).Monien's.
construction.(Redrawn.from.Monien,.H..et.al.,. Fresenius Z. Anal. Chem .,.225,.342,.1967):.1,.screw.(piston);.
2,.turning.head;.3,.electrode.body;.4,.Pt-contact;.and.5,.CP..(Redrawn.from.Kalcher,.K..et.al.,.Heterogeneous.
electrochemical.carbon.sensors,.in. The Encyclopedia of Sensors ,.Vol..4,.Eds..C.A..Grimes,.E.C..Dickey,.and.
M.V..Pishko,.American.Scientiic.Publishers,.Stevenson.Ranch,.CA,.pp..283-429,.2006.and.newly.colorized.)

However,.the.main.motivation.for.future.innovations.of.CPE.holders.was.the.growing.importance.
of.practical.electroanalysis,.when.the.respective.methods.co-opened.once.more.the.problems.with.
illing.wells.of.limited.capacity,.hindering.packing.larger.portions.of.carbon.paste.[31,32,34]..For.
example,.still.more.popular.electrochemical.stripping.analysis.with.CPEs.and.utilizing.extractive.
accumulation.required.the.regular.carbon.paste.renewal—typically,.after.each.measurement..The.
reason.was.that.a.certain.amount.of.the.substance.to.be.analyzed.might.have.remained.entrapped.in.
the.surface.layer.even.after.rediffusion.during.the.stripping/measuring.step.[20,175,.219,226]..And.
if.the.penetration.of.extracted.molecules.into.the.CP-bulk.was.particularly.deep,.solely.a.mechani-
cal.removal.of.the.so-affected.layer—up.to.0.5-1.mm.[217,254]—could.assure.the.acceptable.repro-
ducibility.of.measurements..In.other.words,.such.a.thorough.carbon.paste.renewal.had.also.meant.a.
considerable.consumption.of.the.paste.and.for.that.kind.of.experiments,.another.type.of.CPE.holder.
had.to.be.sought—ideally,.any.other.sophisticated.construction.enabling.the.carbon.paste.extrusion.
and.its.immediate.renewal.