Experiment Cyclic Voltammetry

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Experiment –

Experiment – ELECTROCHEMICAL ANALYSIS OF FERRICYANIDE USING CYCLICELECTROCHEMICAL ANALYSIS OF FERRICYANIDE USING CYCLIC VOLTAMMETRY VOLTAMMETRY 2013-19846; 2013-67188 2013-19846; 2013-67188 November 17, 2016 November 17, 2016 II.. AAbbssttrraacctt

Cyclic voltammetry is classified as a type of potentiodynamic electroanalytical Cyclic voltammetry is classified as a type of potentiodynamic electroanalytical technique used for the study of electroactive species and is extensively utilized in technique used for the study of electroactive species and is extensively utilized in industrial applications and academic research laboratories. In this experiment, industrial applications and academic research laboratories. In this experiment, the formal reducti

the formal reduction potention potential al of ferricyaof ferricyanide was nide was detdeterminermined ed to to be be 0.210.21! " ! " while in contrast, the theoretical formal reduction potential is 0.# ". $he effect of while in contrast, the theoretical formal reduction potential is 0.# ". $he effect of scan rate and concentration on pea% current was observed. &ea% current was scan rate and concentration on pea% current was observed. &ea% current was determined to be directly proportional to both the square root of scan rate 'v determined to be directly proportional to both the square root of scan rate 'v 1(2 1(2

) ) and con

and concentcentratiration. *sinon. *sin+ two stand+ two standard curveard curves of s of Ip ox and Ip red a+ainsIp ox and Ip red a+ainst t concentration, the concentration of the un%nown was obtained usin+ the linear concentration, the concentration of the un%nown was obtained usin+ the linear equations. $he concentration of the un%nown was determined to be

equations. $he concentration of the un%nown was determined to be 7.557.55mM mM .. II. Keywords

II. Keywords: : Formal e!"#tion $otential, %#an ate, Formal e!"#tion $otential, %#an ate, &no!i# $ea' &no!i# $ea' ("rrent, (at)o!i# $ea'("rrent, (at)o!i# $ea' III. Introduction

III. Introduction

(*#li# voltammetr* i+ a i!el* "+e! (*#li# voltammetr* i+ a i!el* "+e! te#

te#)n)ni"i"e e in in or!or!er er to to a#a#""ire ire ""alialitattativeive in

in.o.ormrmatatioion n ababo"o"t t t)t)e e elele#e#trtro#o#)e)emimi#a#all rea#tion+ o##"rrin/ ar!  Fa"l'ner, 2008 rea#tion+ o##"rrin/ ar!  Fa"l'ner, 2008 5t /ive+ a "i#' lo#ation o. re!ox potential+ 5t /ive+ a "i#' lo#ation o. re!ox potential+ o.

o. t)t)e e +pe+pe#ie#ie+ + .o.o"n"n! ! to to be be eleele#tr#troaoa#ti#tiveve ar!  Fa"l'ner, 2008

ar!  Fa"l'ner, 2008 &

& (*#li# (*#li# voltammetevoltammeter r #on+i+t #on+i+t o. o. tt))rreee e mmaaiin n ppaarrtt+ + nnaammeell* * a a oor'r'iinn// el

ele#e#trtro!o!e, e, a a rere.e.ereren#n#e e elele#e#trtro!o!e e anan! ! aa #o"nter ele#tro!e ar!  Fa"l'ner, 2008 #o"nter ele#tro!e ar!  Fa"l'ner, 2008 &

& rever+ible rever+ible ele#tro#)eele#tro#)emi#al mi#al rea#tion rea#tion t)et)e #*

#*#l#li# i# vovoltltamammemetr* tr* prpro!o!"#"#e+ e+ )a)ave ve eellll !e.ine! #)ara#teri+ti#+ +"#) a+ t)e ratio o. !e.ine! #)ara#teri+ti#+ +"#) a+ t)e ratio o. t)e pea' #"rrent+ i+ e"al to one, )e pea' t)e pea' #"rrent+ i+ e"al to one, )e pea' #"rrent+ are proportional to t)e +"are root #"rrent+ are proportional to t)e +"are root o. t)e +#an rate, an! )e po+ition+ o. pea' o. t)e +#an rate, an! )e po+ition+ o. pea' volta/e !o not alter a+ a ."n#tion o. volta/e volta/e !o not alter a+ a ."n#tion o. volta/e +#an rate niver+it* o. (ambri!/e, 201 +#an rate niver+it* o. (ambri!/e, 201

)e +t"!

)e +t"!* * aimaim+ + to to #re#reate a ate a #*##*#li#li# voltammetr* in or!er to t)e

voltammetr* in or!er to t)e .ormal re!"#tion.ormal re!"#tion po

potententiatial l EE00__{ o}_o._{. tt)}_)e_{e F}_Fe_e5555_55(_(N_N 6

6 3-3- <<

Fe55(N

Fe55(N66 4-4- #o#o""pplilinn//, , tto o !!ee.i.inne e t)t)ee

#

#oonn++ee""eenn##ee+ + o. o. ++##aan n rraatte e aann!! #o

#on#n#enentrtratatioion n vavaririanant t o. o. ==33Fe(NFe(N66  onon

p

peeaa' ' ##""rrrreenntt, , aann! ! tto o ""aannttii..* * tt))ee #o

#on#n#enentrtratatioion n o. o. "n"n'n'noon n ==33Fe(NFe(N66

+ol"tion +ol"tion :Fe0(N3 :Fe0(N388;; 3- > > ee-- :Fe0(N3:Fe0(N366;; 4-IV. Experimental IV. Experimental . -toc%

. -toc% &reparatio&reparationn %to#' %ol"tion

%to#' %ol"tion &

& 16462 16462 / / o. o. ==33Fe(NFe(N66  aa++

!i

!il"l"tete! ! iit) t) 001? 1? @N@NAA33 iin n a a 11000 0 mmll

vol"metri# .la+' in or!er to prepare 0 m? vol"metri# .la+' in or!er to prepare 0 m? =

=33Fe(NFe(N66 +to#' +ol"tion +to#' +ol"tion

Beterminin/ t)e Formal

Beterminin/ t)e Formal e!"#tion $otentiale!"#tion $otential an! t)e e..e#t o. %#an ate

an! t)e e..e#t o. %#an ate &n

&n ali"ot ali"ot o. o. 4 4 ml ml o. o. t)e t)e +to#'+to#' +ol"tion a+ !il"te! in a 0 ml vol"metri# +ol"tion a+ !il"te! in a 0 ml vol"metri# .la+' in or!er to prepare a 4 m? =

.la+' in or!er to prepare a 4 m? =33Fe(NFe(N66

+ol"tion +ol"tion

Beterminin/ t)e E..e#t o. Car*in/ %#an ate Beterminin/ t)e E..e#t o. Car*in/ %#an ate an! (on#entration

an! (on#entration &

& var*in/ var*in/ #on#entra#on#entration tion o. o. =

=33Fe(NFe(N66  aa+ + pprreeppaarree! ! iin n 0 0 mmll

vol"metri# .la+' at #on#entration+ o. 2,4,6, vol"metri# .la+' at #on#entration+ o. 2,4,6, 8, 10 m? o. =

8, 10 m? o. =33Fe(NFe(N66  +ol"+ol"tion tion !il"!il"te!te!

it) 01? @NA it) 01? @NA33

Ele#tro#)emi+tr* - (*#li# Coltammetr* Ele#tro#)emi+tr* - (*#li# Coltammetr*

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. /eterminin+ the ormal eduction &otential

)e E#or!er an! $otentio+tat ere +et "p it) t)e or'in/ ele#tro!e poli+)e! "+in/ "e)ler #lot) it) al"mina )e ioniDer+ ere rin+e! an! !r* be.ore +et"p & 2ml o. 4m? =3Fe(N6 +ol"tion a+ "+e!

a+ t)e +tan!ar! )e /reen #lip a+ atta#)e! to t)e or'in/ ele#tro!e, t)e re! to t)e #o"nter ele#tro!e an! t)e *ello to t)e re.eren#e ele#tro!e

)e parameter+ ere +et "p it) t)e initial an! t)e .inal bot) -800mv, t)e rate a+ +et to100mC<+, "pper limit a+ +et to 800mC, an! t)e loer limit a+ +et to -800mC )e +#an+ ere obtaine! an! t)e Epa an! Ep# a+ !etermine! in or!er to

#al#"late .ormal re!"#tion potential C. /eterminin+ the ffect of -can ate

)e +tep+ .or .ormal re!"#tion $otential a+ repeate! at var*in/ +#an rate o. 0, 100, 160, an! 200 mC<+ )e pea' oxi!ation an! pea' re!"#tion a+ !etermine! b* +it#)in/ t)e /rap) to 5E v+ time )e pea' oxi!ation an! re!"#tion a+ plotte! a/ain+t v1<2

an! t)e e..e#t o. +#an rate a+ t)en eval"ate!

/. /etermination of the concentration of the un%nown 3 #4e'C5) 6 solution

& +tan!ar! #"rve a+ ma!e b* repeatin/ t)e +tep+ in !eterminin/ t)e .ormal re!"#tion potential "pon var*in/ t)e #on#entration o. =3Fe(N6 "+in/

2,4,6,8,10 m? =3Fe(N6 +ol"tion+ )e

pea' oxi!ation an! re!"#tion a+ plotte! a/ain+t #on#entration an! eval"ate! t)e e..e#t o. #on#entration on t)e pea' #"rrent )e +tan!ar! #"rve a+ "+e! to #al#"late t)e #on#entration o. t)e "n'non +ample V. Results and Discussion

(*#li# voltammetr* )a+ t)e abilit* o. rapi!l* ob+ervin/ re!ox be)avio"r over a i!e potential ran/e 5t involve+ #*#lin/ o. t)e potential o. an ele#tro!e, )i#) i+

immer+e! in an "n+tirre! +ol"tion an! mea+"rin/ t)e re+"ltin/ #"rrent &n!er+on, 1991

5n #*#li# voltammetr* t)e potentio+tat applie+ t)e !e+ire! potential beteen a or'in/ ele#tro!e /la++* #arbon an! a re.eren#e ele#tro!e Ag/AgCl) 5n a!!ition, t)e or'in/ ele#tro!e i+ t)e lo#ation )ere t)e rea#tion bein/ +t"!ie! ta'e+ pla#e )e a"xiliar* ele#tro!e, t*pi#all* platin"m ire, /enerate+ t)e #"rrent polariDe! nee!e! to maintain ele#trol*+i+ at t)e or'in/ ele#tro!e )e potential o. t)e or'in/ ele#tro!e i+ #ontrolle! ver+"+ a re.eren#e ele#tro!e +"#) a+ a &/<&/(l ele#tro!e )i#) maintain+ #on+tant potential polariDe! &n!er+on, 1991

)e #"rrent re+pon+e .rom an ex#itation potential i+ mea+"re! an! a #*#li# voltammo/ram #"rrent-potential plot re+"lt+ & +#an per.orme! toar!+ a more po+itive potential i+ #alle! an )e ano!i# +#an i+ per.orme! toar!+ a more po+itive potential )erea+ a #at)o!i# +#an i+ toar!+ t)e !ire#tion o. a more ne/ative potential )e re!"#tion potential  o

 #an t)en be #al#"late! "+in/ t)e .orm"la belo an! t)e .olloin/ parameter+

Eo= E pa+ E pc 2 Initial7 8900 m" inal7 8900 m" ate7 100 m"(s *pper limit7 900 m" :ower limit7 8900 m"

)e ano!i# potential an! #at)o!i# potential .or t)e re!ox rea#tion o. .erri#*ani!e a+ re#or!e! to be 0260C an! 01680C re+pe#tivel* %"b+e"entl*, t)e re!"#tion potential   o_{ a+ #al#"late!}

to be 0216 C )e t)eoreti#al re!"#tion potential o. .erri#*ani!e )oever i+ 036 C %tan!ar! e!"#tion $otential+ E0, 2o(, n!

Ele#tro#)emi+tr* - (*#li# Coltammetr*

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Table 1. Data fo I! o" a#$ I! e$ at %a&'#g (a# ate(

Sa# ate

Sa#

ate1/* _{I! o"} _{I! e$}

+, -.,-1,  0.1* 2.+-30 1,, 1, +.+0 .2,01 1, 1*.231 1 -.,3- 3.21-*,, 12.12*1 2 3.1,2  1,.13*- -  3 1, 11 1* 10 12 1+ 1+ 1, + , + 1, 1+ f4") 5  ,.--" 6 ,.*-R7 5 ,.3* f4") 5 ,.-2"  1.+ R7 5 1 Scan rate1/2 Current

F'g8e 1. 9lot of I! o" a#$ I! e$ aga'#(t (a# ate1/*: (;o<'#g t;e e=et of (a# ate.

)e e..e#t o. +#an rate  v  on #*#li# voltammo/ram+ o. 4 m? =3Fe(N6 in 01?

=NA3 a+ ob+erve! at 0, 100, 160, 200

mC<+ 5t a+ !etermine! t)at pea' #"rrent i+ !ire#tl* proportional to  v 1(2 _{ 5t i+ important}

to note t)at a+ +#an rate i+ !e#rea+e! t)e #*#li# +eep o. t)e voltammo/ram ill ta'e lon/er to re#or! )i+ !ata a/ree+ it) an!le+-%ev#i' e"ation at 2(, )erein, n i+ t)e n"mber o. ele#tron+, & i+ t)e ele#tro!e area m2

, ( i+ t)e #on#entration mol<, B i+ t)e !i.."+ion #oe..i#ient m2

<+ an! v i+ t)e potential +#an rate C<+; a+ +#an rate in#rea+e+ pea' #"rrent in#rea+e+

Table 2. Data f _{o I! o" a#$ I! e$ at %a&'#g}

o#e#tat'o#( of fe'&a#'$e Co#e#tat'o # I! o" I! e$ * *.3+- 2.+-30 2 +.+0 .2,01  3.1-*,2 11.2+- 1*.,221 12.2+-1, 12.033 1-.23* U#>#o<# 11.+133 10.2+1 1 * 0 2 +  -  3 1, 11 *, 1+ 1, + , + 1, 1+ *, f4") 5  1.1"  1.- R7 5 ,.33 f4") 5 1.2+" 6 ,.1-R7 5 1 Concentration Current

F'g8e *. 9lot of I! o" a#$ I! e$ aga'#(t o#e#ta'o#: (;o<'#g t;e e=et of o#e#tat'o#.

5t a+ !etermine! t)at #on#entration a..e#t+ t)e ma/nit"!e o. t)e pea' #"rrent Fi/"re 2 +)o+ t)e pea' #"rrent+ at var*in/ #on#entration+ o. 2, 4, 6, 8, an! 10 m? o. =3Fe(N6 in 01 ? =NA3 at 100

mC<+ )e !ata +)o+ t)at pea' #"rrent i+ !ire#tl* proportional to #on#entration )i+ +tan!ar! #"rve #an t)en be "tiliDe! to eval"ate t)e #on#entration o. t)e "n'non +in#e t)e 5p ox an! 5p re! o. t)e "n'non a+ obtaine! to be 11199 m& an! -13481 m& re+pe#tivel*

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-ample computations for un%nown *sin+ Ip ox 7 11.!1;; y=1.4508_x+0.1744  11.5199 ¿=1.4508 x+0.1744 x=11.5199− 0.1744 1.4508 x=7.82_mM *sin+ Ip red 7 81#.<9!1 y=−1.6111_x−1.7619

(

−13.4851

)

=−1.6111 x−1.7619 x=−13.4851 +1.7619 −1.6111 x=7.28_mM (on#entration o. "n'non ¿ 7.82+7.28 2 ¿ 7.55_mM VI Conclusion

)e ele#tro#)emi#al anal*+i+ o. .erri#*ani!e, =3Fe(N6, "+in/ #*#li#

voltammetr* a+ +"##e++."ll* per.orme! in !eterminin/ t)e .ormal re!"#tion potential o. .erri#*ani!e )e e..e#t+ o. +#an rate an! #on#entration on t)e pea' #"rrent+ ere

ob+erve! an! vi+"aliDe! on t)e voltammo/ram+ Finall*, t)e #on#entration o. t)e "n'non a+ extrapolate! "+in/ t)e +tan!ar! #"rve

5t i+ re#ommen!e! t)at be.ore ea#) part o. t)e met)o!olo/*, t)e or'in/ ele#tro!e be poli+)e! "+in/ a "e)ler #lot) it) al"mina at +"..i#ientl* in or!er to obtain better re+"lt+ in t)e voltammo/ram+

VII Reference &n!er+on, & G 1991 :C$=C>?I-$@  etrieve! .rom $@&5?E%: )ttp:<<p)attime+#om<m*o/lobin <#)apter3)tm

ott, & H,  Ga#'+on,  $ 1996 %t"!* o. Ferri#*ani!e b* (*#li# Coltammetr* +in/ t)e (C-0H Current -eparations4

ar!, & G,  Fa"l'ner,   2008 lectrochemical ?ethodsA undamentals and pplications. Ni#)ol+on,  % 196 )eor* an!

&ppli#ation o. (*#li# Coltammetr* .or ?ea+"rement o. Ele#tro!e ea#tion =ineti#+ nal. Chem

$an!"ran/a#)ar, ?, %am*,  E, ()an!ra+)e'ar,  N, Iilbert, A, e!!*, %,  %%)eri/ara,  2010 Ele#tro#)emi#al 5nve+ti/ation+ o. $ota++i"m Ferri#*ani!e an!Bopamine b* 1-b"t*l-4-met)*lp*ri!ini"m tetra.l"oro borate ?o!i.ie! (arbon $a+te Ele#tro!e: & (*#li# Coltammetri# %t"!*  International Bournal of lectrochem -cience

niver+it* o. (ambri!/e 201 :inear -weep and Cyclic "oltametryA $he &rinciples etrieve! .rom

Ele#tro#)emi+tr* - (*#li# Coltammetr*

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Bepartment o. ()emi#al

En/ineerin/ an! iote#)nolo/*: )ttp:<<#eb#ama#"'<re+ear#)</

ro"p+<r/-eme<tea#)in/-note+<linear- +eep-an!-#*#li#-voltametr*-t)e-prin#iple+