and Fe Ions Using a Technique of Flow Injection Analysis Development of an Analytical Method for the Spectrometric Simultaneous Determination of Fe  

Printed in the Republic of Korea

  Fe

 Fe

 

   

*

  

(2002. 6. 11 )

Development of an Analytical Method for the Spectrometric Simultaneous Determination of Fe

and Fe

Ions Using a Technique of Flow

Injection Analysis

Hoon Hwang* and Jinho Kim

Department of Chemistry, Kangwon National University, Chunchon 200-701, Korea (Received June 11, 2002)

.   H²O2  Fe²⁺  (Fe²⁺Fe³⁺) Fe³⁺ SCN⁻  

Fe(SCN)3−xx  ! " #  $% &'(%)*+, -. Fe²⁺ Fe³⁺ /0" 12 .3 4 5 6 7189 : )*, ;<=>.  )*, ;? 6  89@A B C

12 DEF(Fe²⁺ GH I Fe³⁺ GHJ)@AK LMN " +0 )*,6" OF P Q R @A6 71 ST  U>" VW QX>.  )*, Y8A" [Fe³⁺]=6.00Z10⁻⁷ M[>.

: &\(%)*, ](II), ](III)

ABSTRACT. An analytical method for the spectrometric simultaneous determination of the individual ions in the mix- tures of Fe²⁺ and Fe³⁺ ions utilizing a technique of flow injection analysis has been developed. The method was based on the oxidation reaction between Fe²⁺ ion and H2O2 in an acidic medium and the subsequent formation of a red Fe(SCN)x3-x

ion by the complexation reaction between Fe³⁺ ion and SCN⁻ ion. Unlike the conventional methods which require separate processes for the pre-treatment of the sample solution, the current method uses the same FIA system for the pre-treatment and the analysis of the sample. The detection limit for the determination of Fe³⁺ ion was found to be 6.00×10⁻⁷M.

Keywords: Flow Injection Analysis, Fe(II), Fe(III)

 

(^X .3 0_" Fe²⁺ ` .3 a

>b Fcd(ligand)6 e>f H²Og  h

ij k" Fe(H²O)6

2+ !lm 0_"n, ( o/+ pqrf Fe(H²O)6

3+sm tu  v>.

wxsm .3 w^y" Fe²⁺  "

Fe²⁺  Fcd z{, .3 | `F}

pH ~ ` 8$Q >€u y‚>. Fe²⁺ ƒ

„" .3 Fe²⁺   … Fe³⁺

† rf, >‡ @Am Fe³⁺ Q)…(Fe³⁺+ 3H2O=Fe(OH)3+3H⁺) w^‚>. 4 y ˆ+ . 3" ‰ Fe³⁺ Q)… ŠXr^

† ‹Œ Fe(OH)³(s) … .3 xsm oR

Ž,  .3" Q)… r^ Fe²⁺

  ‘1 ’  U>. “, |”Q (u 

(donor atom)Œ Fcd6 Fe²⁺ Hx •8

#‹ ! + –— Fe²⁺  K T  U>. Gm˜, 1, 10-phenanthroline" Fe²⁺ 

  Fe(phen)3

2+(ferroin:  -J R1

™) ! š,  # ›(
   …

Ž h œb Fe(phen)³³⁺sm  ’  U>.

Fe²⁺ ƒ„" .3 w^y" Fe²⁺

  g ` ~b Fe²⁺ $o " žŸ 1 2 4 ƒ„v Fe²⁺  89 ¡ xR ¢

V£K i¤T  U>. ~ Fe²⁺ ƒ„" . 3 w^y" Fe²⁺  K + :… . 3 pH=2~38$
  sm Ž6^(}, |”K

¥1¦(bubbling) .3 4 §› U" ”K L … ¨ ©, 4^oC $ ª;Q U" „F«

y ¬F­® .+ ¯°>. `‰y ‰ p±

$ ²³} ` a$" ´FRŽ Fe²⁺  "  Dµ XS’  U>. ~ (^X $ Fe²⁺

.3 0_" Fe²⁺ Fe³⁺ $K ¶›·

+ : )*, ¸¹ ºš, »_ .3 4 Fe²⁺

 Fe³⁺ 89+ :… >Ÿ )*,6^1-9 (¼u)*, x8)*, Q1½ )¾)*, ¿ “"

Àq )¾)*, X-½ )*, D+)*, &'(%)

* Á) ;<r^ -.r} U>. `‰y 6 +0

)*,6 ÂÃ Fe²⁺ Fe³⁺ C12 4 ;

?6  )F89 S+ :…" 12 .3 a Fe²⁺ ÄP Fe³⁺sm ÅÆ" GH  @Ay 12.3 4 Fe³⁺ ÄP Fe²⁺sm oJ" GHJ@AQ ½Sr^N >" ÇLmÈ ·É} U>.

 ³" Fe²⁺ Fe³⁺ /0" 12 4 5  )F89 :… Fe²⁺ H2O2 -

 -J Fe³⁺ SCN⁻ - # 

 $% &'(%)*+, -. 12 G HEF@Ag ʐ)*@AK 71 ST  U"

)*, ;<=>.

FIA system.  ÊË -. FIA system A¥

$Q Fig. 1 ÊÌU>.  system" peristaltic pump(B, Ismatec MV Pump System)g 3; channel 6 -.š, 5 channel ¥ .3 Í :…

" Tygon pump tubng(i.d.: 0.44 mm, Cole-Parmer Instrument Company)6 -.=>. “, pump©

 system· ÄÎ line6 :…" ·Â 0.38 mm

Œ ÏÐÑ°(PTFE tubing) -.=>. Sample injection valve(C, Rheodyne 6-port valve, loop volume:

110µL) … (%v 12.3(Fe²⁺ Fe³⁺

 /0"  .3) pump Ò ÇÓ channel ¥

 ‹ &' ~ FIA system ·Ôm Ív>.

12.3 &' Ò ÇÓ mixing T(D) pump

P ÇÓ channel ¥ .3 &' Ռ © Ö w(reaction coil)(E) ¥u v>. Pump P ÇÓ channel Âà pumpD ×Ø 3-way valve(A)

… ¸¹ ~ ‹ &' H²O2.3 &' ½ ÙT  U$j =>. 3-way valve ‹ &'

½Ùr" ÂÃ" P ÇÓ channel ¥ ‹ &'

 12.3 Õ" Ò ÇÓ mixing T" ›¼Ú  w^yR ¢sš, 12.3 4" Fe²⁺

 Fe³⁺ `m /0u v>. `‰y 3-way valve H²O2.3 &' ½Ùr" ÂÃ" Ò Ç Ó mixing T H2O2  Fe²⁺  Q w^

y 12.3" Fe³⁺Ž 0_u v>. Ö w ™ 10 cm8$ PTFE tubing ÛÜ !lm Ý

›   ºsm mixing tee MÞ yß" P Q R .36 àw Õá   â „$

>. Ò ÇÓ mixing Tg Öw R‚ .3 &'

 P ÇÓ mixing T(F) pump ã ÇÓ channel

 Žy"n, P .36 P ÇÓ Öw ¥

f 12.3 4 Fe³⁺ ã ÇÓ channel &€

" SCN⁻ Žy  Fe(SCN)3−xx  † r" #  XSv>. P ÇÓ Öw R‚

.3 &' +ɐLŒ(de-gassing line)(H) ¥ Fig. 1. Schematic Diagram of the FIA System. A: 3-way valve, B: peristaltic pump, C: sample injection valve, D: first mixing T, E: reaction coil, F: second mixing T, G: reaction coil, H: de-gassing line, I: detector, J: recorder.

 ©, äq+(I, UV/VIS detector, 10µL flow through cell V#, å¿æV: 480 nm, Spectra Physics)K ¥

f .3 4 Fe(SCN)^x3−x  ¿¾$Q Y 8v>. +ɐLŒ  ÊË  v FIA system

 <† +É(H2O2.3 )… Á … <†)6

 äq+ „%r^ i¤T  U" äqçè ²•

8, é, êçè <† ÀR} ×Ø=>. +É

LŒ 30 cm8$ ëã >/ ¬Fìm¸® í

°(·Â: 400µm, pore size: 0.2µm, îà /$<porosity>:

~40%, ï¡ð: Celagard X-20, Hoechst-Celanese) Ÿ ñ ò ·Ôm 25 gauge (-Åó6 ô%  

=>. +ɐLŒ FIA system -. PTFE°

  :… (-Åó Ÿñ ò Ô) xõ

ö+ PVC° ·Ôm ô% © PVC° >b ñ ò Ô) ·Ô" PTFE° ô%=>. “, +É

LŒ +ɐL÷ø ù1ú+ :… ¸¹

back pressureK  + :… FIA system ò Ô)

 v äq+ drainÔ) û ·Â ü PTFE

°  ©, ° ò Ô) ý)µ þ ÿ : Ø1
>.

FIA system    .  ÊË -.

 FIA system" 7w 12.3 P Ç (%

 `mÔ P ; çè(peak)6 uv>. Pump

D ×Øv 3-way valveK õ P ÇÓ channel ¥… ‹ &' ½Ù ©, sample injection valve K ¥… Fe²⁺ Fe³⁺ /0"  12.

3 Ò ÇÓ (% ^X>. Ò ÇÓ mixing T

 ‹ ÕX 12.3 P ÇÓ mixing T KSCN .3 Žy},  RW 12.3 4 Fe³⁺

SCN⁻-  XSr^  Fe(SCN)^x3−x

 ŽÎ>. † v Fe(SCN)x3−x ¿¾$Q ä q+ Y8r}, äq+ v +j+ 12 .3 Ò ÇÓ (% … ^X Ò ÇÓ peakQ + jv>. Ò ÇÓ peakQ +jv © 3-way valveK õ

 P ÇÓ channel ¥… H²O2.3 &' „$

>. P ÇÓ channel ¥ H²O2.3 FIA system âDµ ¥" 1W €f 7w 12.3

P ÇÓ (% ^X>. 12.3 Ò ÇÓ mixing T P ÇÓ channel H²O2.3 &' Žyf 1 2.3 a Fe²⁺ H2O2 … Fe³⁺sm  v>. © Fe³⁺Ž ƒ„ 12.3 P ÇÓ mixing T KSCN.3 Žy Fe³⁺ SCN⁻

- #  w^y} `  +j+" P Ç Ó peakQ +jv>. Žw 12.3 Fe²⁺Ž 0 _" ÂÃ" +j+" Ò ÇÓ peak" yyR

¢} P ÇÓ peakŽ +jr"n, P ÇÓ çè ö +(peak height)" 12.3 4 Fe²⁺ $g H

°AK yyu v>. Žw 12.3 Fe²⁺ Fe²⁺

 /0" ÂÃ P ; peak6 ÄP +jv

>. é, Ò ÇÓ peak" 12.3 4 Fe³⁺ 

º}, P ÇÓ peak" 12.3 4 Fe²⁺ Fe³⁺

 ÄP … ^X º>.

. FeSO⁴· 7H2O(extra pure, Junsei Chemical)g Fe(NO3)3· 9H2O(extra pure, Junsei Chemical) ~0.14 M HNO3.3 § stock solution6  ©, 5 stock solution6 xõµ (~0.14 M HNO³.3 .Ûm -.) ¸¹ $ .36 =>. HNO³ .3 -. „" Fe³⁺ Q)…K ÀR+

:…>.¹ HNO3.3 -.sm Fe²⁺ .3

 Fe²⁺  Q rš " Fe³⁺ Q )…K  .3 Fe(OH)3.3sm o" º ÀR+ –—>. `‰y Fe²⁺ ¨.36  Ã" ÄÎ .36 -.D =>. “, KSCN(extra pure, Junsei Chemical) X H2O2.3 ($: ~30%) -. ¸¹ $ KSCN H²O2

.36  -.=>.  ÊË" ¸¹

ÂÃ i(pure water, Milli Q, Academic, Millipore) K -.=>.

 

KSCN .  ÊË" Fe³⁺

SCN⁻- #  .>[Fe³⁺+xSCN⁻= Fe(SCN)x3−x(+ x=1, 2, 3, 4, 5, 6)].   † ‹ SCN⁻ $ ~ >Ÿ !l 

6 † ’  Usš, 6 #6 Fe(SCN)x3−x

sm »T  U>. ~ $:Q 10⁻⁶M~10⁻³ M €" Fe³⁺  Berer , ~€

" Fe(SCN)x3−x6 Ž6^  U" SCN⁻

 åx$K ¶› ¸¹Q U>. K :… P QR

$(4.00Z10⁻⁵M 1.00Z10⁻³M) Fe³⁺ >Ÿ

 $(0.010, 0.050, 0.10, 0.20, 0.40, 0.60, 0.80, 1.0, 1.5, 2.0 M) SCN⁻ m 1 ©, † v Fe(SCN)x3-x  ¿¾$(å¿æV: 480 nm

-½S³ )6 °=>(Table 1: ï [SCN-]

=0.010, 0.10, 0.20, 0.40, 0.80, 1.0 M ÂÃ …

" dataŽ Ê[‡). Table 1 f Fe³⁺ $

Q  ÂÃ(4.0Z10⁻⁵ M) SCN⁻ $Q 0.10 M

€f Fe(SCN)^x3-x  ¿¾$Q »µ ù Qƒ ¶  U>. " Fe³⁺ ƒ„" .3

$Q Ûà  Âà Fe³⁺ SCN⁻- 

 m w^y+ :…" ý) Ÿ SCN⁻

([SCN⁻]0.10 M) /… (^N ƒ ë>.

`‰y SCN⁻ $Q 0.10 M¯>  X…R" ÂÃ

" ¿¾$ ùQ `F öR ¢‡$   U>.

Fe³⁺ $Q X([Fe³⁺]=1.00Z10⁻³ M) ÂÃ$

H K   URŽ, Fe³⁺ $Q 

ÂÃg" OF SCN⁻ $Q 0.10 MïŒ ‘

 SCN⁻ $Q ùQ$ ¿¾$" L o

R ¢‡   U>. " Fe³⁺ $Q X

ÂÃ" SCN⁻ $Q 0.10 M8$ €f L

 Ô) Fe³⁺ Fe(SCN)x

3-xsm o+ –

—sm †5T  Usš, ~ 0.10 M¯>  X

$ SCN⁻ -. ²¸¹ƒ ¯(" º

>. `‰y  $ Fe³⁺ … ¯>  þ

¿¾$K   U>" º )*, Y8A(limit of detection, LOD)"   ›|  U>" -Ê ë>. ~  ÊË" X $(1.00Z 10⁻³M) Fe³⁺ -.  ¯>" 

$(4.00Z10⁻⁵ M) Fe³⁺ … ^X 

¯>  H4 Pu r[>. ~ SCN⁻ 

$Q ùQƒ ~ ^R" peak height o Ä!

¶›¯"sš, ` " >‡ #>. Table 1 

f [Fe³⁺]=4.00Z10⁻⁵MŒ Âà SCN⁻ $Q 0.20 M rf 0.10 MŒ Âà H… peak heightQ ™ 1.1$ ùQ}, 040 M rf 0.20 M H… peak height Q ™ 1.17$ ùQ, 0.80 M rf 0.40 M H… peak heightQ ™ 1.13$ ùQ=>. é, SCN⁻ $

Q 2$ ùQrf Y8v peak height o Hø

0.20 M 0.40 Mm ùQ" ÂÃQ QV öu y

%>. & Hj ›( X $(G, 2.0 M) SCN⁻

 -." Âà  $ Fe³⁺  ¿¾

$m >”  '  " U(RŽ )* 

)•>f SCN⁻ åx$m˜ 0.40 M 8

$ ' ½Ù" º Å*> T  U(>. 

 Fe³⁺ SCN⁻ -   +

—,¹⁰" P 6 - smÔ † r"

Fe(SCN)x3-x  ¿¾$g Fe³⁺ $-

 °A" ‰ QR ¹Œ6 … Beer , ` F - ~€R .T $ URŽ, ý)µ X $

SCN⁻ -." Âà / $‘ Fe³⁺

  Beer , 0’  U>" -Ê ¶  U>. “, $Q 0.5 MŒ SCN⁻ -."

Âà † r" Fe(SCN)^x3-x å¿æV 480 nm á 1µ} U>. ~ Bg # ÊË6

—, ·. 2L © ÊË" KSCN.

3 åx$m 0.50 M -.=>.

H2O2 .  )*," H2O2K - .  12.3 ƒ„v Fe²⁺ Fe³⁺s m  (2Fe³⁺+H2O22Fe³⁺+2OH⁻)1 ©, >‡ @A m Fe³⁺ SCN⁻- #  „$u v>. ~ $:Q 10⁻⁶M~10⁻³ M €" Fe²⁺

  K „$u ’ »_ FIA system -.

T H2O2.3 åx$K ¶›¯">. K :… >

Ÿ $(4.00Z10⁻⁶ M, 4.00Z10⁻⁵ M, 4.00Z10⁻⁴ M)

 Fe²⁺  K :… 0.010 M, 0.10 M, 1.0 MŒ

H2O2K -. ©, † v Fe³⁺smÔ Ž6^X Fe(SCN)x3-x ¿¾$K Y8 H²O2 $Q

¿¾$ ëØ" 3 -=>(Table 2). Table 2

 f [H2O2]=0.010 MŒ Âà QV  $

(4.00Z10⁻⁶ M) Fe³⁺smÔ QV peak height K   Us4m 0.010 M H²O2.3 -.sm )*, Y8AQ QV ›|  U>" 58 Q 6>. `‰y Fe²⁺ $Q ¯>  X…Rf peak height6 W  ›7 ¯Œ>. é, Fe²⁺

$Q 100$ ùQƒ ~b peak height ùQHø

85$ 8$ `Ø} Usš, " Fe²⁺ )*

)$(sensitivity)Q ›|  U>" -Ê ë>.

1.0 M H2O2.3 -.= ÂÃ" Fe²⁺

$o  ~b peak height o Hø 10$ ï (4.00Z10⁻⁶M4.00Z10⁻⁵ MŒ Âà 11.3$ ùQ, 4.00 Table 1. The comparison of the peak heights obtained from the

reaction of Fe³⁺(4.00×10⁻⁵ M and 1.00×10⁻⁴ M) with SCN⁻ of various concentrations

KSCN, M 0.01 0.1 0.2 0.4 0.8 1.0 [Fe³⁺]=4.00×10⁻⁵ M 14 625 694 816 922 965 [Fe³⁺]=1.00×10⁻⁴ M 11 103 107 110 - -

Z10⁻⁵ M4.00Z10⁻⁴ MŒ ÂÃ" 10.8$ ùQ)sm y%sš, ~ >b $(0.01 M 0.10 M) H2O2

.36 -." ÂÃ H… )*, )$"  8

|  U‡ ë>. `‰y Fe²⁺ $Q Q V (4.00Z10⁻⁶M) Âà QV  peak heightK y·"n, " H²O2.3 $Q 0.010 M 0.10 M

Œ Âà H… Y8A"  þ›|  U‡ ë

>. &  ÊË" Fe²⁺  )* ¯

> / $: 9M Q6} 71 Q6 

 Y8AK 5³} Us4m 1.0 M H²O2.3

-. `F Å*R .> T  U>. g" O F H²O2.3 $Q 0.10 MŒ ÂÃ" QV 

$ Fe²⁺  ¿¾$ Âà 0.010 M H … `F  R ¢sš, 71 Fe²⁺ $Q X

ÂÃ ^X ¿¾$Q QV '64m Fe²⁺

  )*, Y8Ag )$ P QR °W6 ÄP U^ QV Å* ºsm †5T  U>.

>Ž,  Âà Fe²⁺ $ùQ ~b peak height

 ùQHø 1.0 M H²O2.3 -. H… >” 

›7   U>. é, H2O2.3 $Q 1.0 MŒ  Ã" Fe²⁺ $Q 4.00Z10⁻⁶ M4.00Z10⁻⁵M m ùQƒ ~ peak height" 11.3$ ùQ} >1 Fe²⁺ $Q 4.00Z10⁻⁵ M4.00Z10⁻⁴ Mm ù Q ÂÃ" 10.8$ ùQ Fe²⁺ $ùQ

 peak height ùQHø ™ 4.4% )” f, H2O2.3 $Q 0.10 MŒ Âà 55 10.6$g 9.6

$m ™ 9.4% )”K ¯=>. ~ g # peak

height o Hø)”»ï ¯â+ :… © Ê

Ë" 0.20 M H2O2.3 -.=>.

FIA system . Fe³⁺ SCN⁻-

  † ‹Œ Fe(SCN)^x3−x Âà `  ß : 1c7• „RrR .>. ` „" SCN⁻

… Fe³⁺ J’  U+ –—š, ;< p qr" Âà ` 8$Q =…X>.⁵~ Fe³⁺

SCN⁻  † v Fe(SCN)^x3−x ¿¾

$" Q6 >b 1c · Y8r^N >. `‰y

>b sm" H²O2  Fe²⁺  g Fe³⁺

 SCN⁻- #  :" å”

 1c (^ÞN 4m  ÊË -. FIA system x.…N T åx„a ?›¯">. K :… 0.20 M H²O2 0.50 M KSCN, `F} 1.00Z10⁻⁴ M Fe²⁺ .3 -. FIA system „a ¿

¾$- °AK H=>. `   ÊË

-. FIA system ÂÃ pump a$o  ~b

¿¾$ o " ›(  u y%sš, ~ )*,

 ça   }Ì »_ FIA system

0.742 mL/min „a y·$j pump  7a$

K }8=>.

Fe(SCN)x3−x   H²O2 !-"

#. ë + Åg #  ÊË -."

FIA system Âà 7w 12.3 P Ç (%u v>. 12.3 Ò ÇÓ (% pump P ÇÓ channel ¥… ‹ &€" 7• ^Rš, P ÇÓ (% P ÇÓ channel ¥… H2O2.3 &€" 7

• ^X>. ~ Žw 12.3 Fe³⁺Ž

0_" ÂÃ" þQ m # P ; peak6   U^N >. `‰y pump P ÇÓ channel ¥ H²O2 &' Fe(SCN)^x3−x •8$

(stability) 3 ë@>f, 7w 12.3(Fe³⁺

Ž ƒ„) (%sm ur" P ; peak6

þQ m O| Q U>. ²Su$  ÊËÊ

 S beaker scale experiment f, Fe(SCN)^x3−x

 ƒ„ .3 X $(~3%) H2O2.3 Q" Âà Fe(SCN)^x3−x  -R" » ï °Y=>. ~ FIA system -." ÊË

$ (^X $ Fe³⁺ ¨.3smÔ ^

Ru ’ P ÇÓ peak þQ Ò ÇÓ peak þ

H… >”  º" -Ê GYT  U>. Aµ, Table 2. The comparison of the peak heights obtained from the reaction of Fe³⁺(4.00×10⁻⁶ M, 4.00×10⁻⁵ M, and 4.00×10⁻⁴ M) with 0.50 M SCN⁻ in the presence of various concentrations of H2O2

[Fe³⁺], M Rlative peak height

0.010 M H2O2 Relative increase 0.10 M H2O2 Relative increase 1.0 M H2O2 Relative increase

4.00×10⁻⁶ 1126.28 1(1) 023.00 1(1) 1119.241 1(1)0

4.00×10⁻⁵ 1237.63 9.03(9.03) 243.49 10.59(10.59) 217.14 11.29(11.29)1

4.00×10⁻⁴ 2240.85 19.43(85.15) 2347.290 0.9.64(102.09) 12341.3100 10.78(121.71)

/ $:(10⁻⁶ M~10⁻³ M) Fe²⁺ )*

Fe²⁺ âD  K :… 0.20 M H2O2.3 -." »_ FIA system" H²O2  `‰

 3 ¼1T  eu v>. é, 12.3B> Fe²⁺

 Ÿ m öu >€>f Fe²⁺  1ú } C" H²O2 Ÿ »µ O| º}, & 12 .3 ~ H²O2  3 >€u yD ºsm GYT  U>. ~ H2O2 $o Q Fe(SCN)x3−x

 •8  ëØ" 3 89xsm Eð…N T

¸¹Q Usš,  ÊË" $:Q 1.00Z10⁻⁶ M~8.00Z10⁻⁴ MŒ Fe³⁺ ¨.36 ëØ"

H2O2(0.20 M) 3 ¶›¯">. Fig. 2" Fe³⁺

¨.36 (%  Ò ÇÓg P ÇÓ peak height6 [Fe³⁺]  $1 º>. + -.

v peak height6 ÄP .Ûm -. 0.1 M HNO³

 ƒ„v ë9 Fe²⁺ Fe³⁺  peak height (blank value)K F^¨ '6>.  `G ~€f, B

 ë GY Åg # Fe³⁺ $ ~

H2O2 … )…r^ -R" Fe(SCN)^x3−x Ÿ

 >€š, Fe³⁺ $Q X…Rf H2O2 

3 )”ƒ   U>(`‰y Fe³⁺ $Q X…|j )…r" Fe(SCN)^x3−x õxŒ Ÿ

 H›X>). & 7w $ Fe³⁺ ¨.3 -. " P ; peak6 H²O2  3 –

— m >b þK ¯}, ‰ peak height

Q ÄÎ $ 7w Høm$ yyR ¢s 4m C12 4 Fe²⁺ Fe³⁺  89

`F c@  ¡ ›I º>. `‰y >S º

Fig. 2   UJ (^X $: · 55

 peak height6 Fe³⁺ $o  … ½ xsm o " Ä! ¯Œ>" -Ê>. ~ (

^X )* Fig. 2g # ä8½ Ly x õ Fe³⁺ ¨.36 -. 12 4 Fe²⁺

 Fe³⁺  89 Q6… |  U" º>.

12.3 4 Fe²⁺ Fe³⁺ 89. »_ FIA system -. Fe²⁺ Fe³⁺  898 ×ðf >‡ #>. Fe²⁺ Fe³⁺ /0

" 12.3 -. P ; peak height6 ³

 ©, P ÇÓ peak heightK Fig. 2g # ä8½

Hf 12.3 ƒ„v Fe³⁺ DK$(CD K=¤ 12 4 0_L Fe³⁺ Fe²⁺

H2O2 …  r^ †M‚ Fe³⁺=[Fe³⁺]+[Fe²⁺]) K ³T  U>.  12.3 Ò ÇÓ peak height (h1st)g P ÇÓ peak height(h2nd)K -. N(OCDK Z(h^1st/h2nd)=[Fe³⁺]P) … ¤Ô 12.3 0 _L Fe³⁺ $([Fe³⁺])K ³>. BRísm OC
-[Fe³⁺]=[Fe²⁺]P … 12.3 4 Fe²⁺

$([Fe²⁺])K A>. Table 3 1.00Z10⁻⁵ M 1.00 Z10⁻⁴ M Fe²⁺ ¨.36  ©, 11cB>

5 12.3(Fe²⁺ ¨.3) a C›U" Fe²⁺

 † v Fe³⁺ $K Y8 K ¯¨

>.  ÊË" ë 12.3 $(C
^=[Fe³⁺] +[Fe²⁺]=Fe²⁺ ¨.3 $)6 ¶ÌÞ Us4 m Fe²⁺ Fe³⁺ 89 P ÇÓ peak height 6 -.T ¸¹Q e[sš, B ³ ä8½ -.R ¢} ¸¹T –B> xõ $ Fe³⁺

¨.36 -.=>. é, (^X $ 12.3 (% Ò ÇÓ peak height(y: 12.3 4 † r^ U" Fe³⁺  peak height)K ">. P QR $(12.3sm -. Fe²⁺ ¨.3

$¯> Q  $g Q X $) Fe³⁺ Fig. 2. The Calibration Curves - the magnitudes of the two

signals obtained from the Fe³⁺ standard solutions in the range of 1.00×10⁻⁶ M~8.00×10⁻⁴ M.

 ¨.36($: M1 M2, M2>M1) -. 5 .36  Ò ÇÓ peak height6 ">(x¹ for M1, x2 for M2).  (M¹, x1) (M², x2)K -. linear regression … >‡ # N BR>.

x={(x2-x1)S(M²-M1)}M+(x1M2-x2M1)S(M²-M1)

+ x" 12.3 4 0_L Fe²⁺ ÄP Fe³⁺sm  v Âà y·" Ò ÇÓ peak height

}, M 12.3sm -. Fe²⁺ ¨.3

$(“", C
)>.  12.3 4 †My U

" Fe³⁺ %0_HøOySxZ100P, Fe³⁺

$"OFe²⁺ ¨.3 $(C
^)ZySxP, ` F} C›U" Fe²⁺ $" OFe²⁺ ¨.3

 $(C
)-[Fe³⁺]P … ³>. >‡ ʐ Ê Ë Sv QR 898 Gm Î º>. 1.07 Z10⁻⁴ M Fe²⁺ ¨.3  ©, 11c Â

 1W  Ò ÇÓ peak height" 0.530}, 7.84Z10⁻⁵ M 1.96Z10⁻⁴ M Fe³⁺ ¨.36

… ^X Ò ÇÓ peak height6 55 44.43

112.47[>. ~ (x¹=44.43, M1=7.84Z10⁻⁵ M)

(x2=112.47, M2=1.96Z10⁻⁴ M) M=1.07Z10⁻⁴ M : N x.f 12.3 4 ÄÎ Fe²⁺ Fe³⁺

sm  r" Âà ur" 12.3  Ò Ç Ó peak þ(x)" 60.98m Av>. `Ún ʐ 1 2.3 … ^X Ò ÇÓ peak height" 0.530

4m 12.3 4 Fe³⁺ ƒ„Hø 0.869%},

mÔ [Fe³⁺]=9.30Z10⁻⁷ M, [Fe²⁺]=9.907Z10⁻⁵ M g # '6 ^X>. Table 3 ÊT $6([Fe²⁺]

 [Fe³⁺]) ‰ 86 ¥… ³ '6>. Fig.

3 B ÊË(Table 2)g 4.00Z10⁻⁵ M Fe²⁺

 ¨.3 -. ÊËK 2Lm 1c Â

ƒ ~ >Ÿ $ Fe²⁺ ¨.3 <†"

Fe²⁺  8$K ¯(} U>. @, 4.00×10⁻⁵ M Fe²⁺

 ¨.3 -. ÊË Âà >b P .36 -. ÊË6 + D 1c ƒ ~

Fe²⁺  r" Â3 ¶›¯+ :… ;Uxsm S ÊËš, ~ ã dataK y 

e[>. Fig. 3 ~€f Fe²⁺ ƒ„"  .3 (~0.14 M HNO3 .Ûm -.)6 Âà $Q ^

|j 1c Ârf Fe²⁺  Q ïxs Table 3. The variations of [Fe²⁺] and [Fe³⁺] in the Fe²⁺ standard solutions as a function of time

[Fe²⁺]initial, M 1 hr 2 hrs 3 hrs 4 hrs 5 hrs 6 hrs 7 hrs

1.00×10⁻⁵ [Fe²⁺] 9.23E-6 9.19E-6 9.02E-6 8.87E-6 8.56E-6 8.12E-6 8.39E-6 [Fe³⁺] 8.06E-7 9.81E-7 1.13E-6 1.55E-6 1.88E-6 2.58E-6 3.88E-6

1.07×10⁻⁴ [Fe²⁺] 1.0607E-4 1.0468E-4 1.044E-4 1.0432E-4 1.037E-4 − 9.69E-5

[Fe³⁺] 9.30E-7 2.32E-6 2.60E-6 2.68E-6 3.30E-6 − 1.01E-5

[Fe²⁺]initial, M 8 hrs 9 hrs 10 hrs 11 hrs 12 hrs 13 hrs 14 hrs

1.00×10⁻⁵ [Fe²⁺] 6.12E-6 4.32E-6 2.27E-6 8.60E-7 1.70E-7 0 −

[Fe³⁺] 5.68E-6 7.73E-6 9.14E-6 9.83E-6 9.83E-6 1.00E-5 −

1.07×10⁻⁴ [Fe²⁺] 9.15E-5 7.93E-5 6.24E-5 3.53E-5 6.00E-6 1.00E-6 −

[Fe³⁺] 1.55E-5 2.77E-5 4.46E-5 7.17E-5 1.01E-4 1.06E-4 −

Fig. 3. The Oxidation of Fe²⁺ as a Function of Time.

m VF XSv>" -Ê   U>. “, Fe²⁺

  ÀRK : ?$ ØK WR ¢">f, Fe²⁺  ¨.36  © 12~141c Â

f Ô) Fe²⁺ Fe³⁺sm  X

¶  U>.

 

  H²O2  Fe²⁺  (Fe²⁺ Fe³⁺) Fe³⁺ SCN⁻  

Fe(SCN)x3+ ! " #  $% &'(

%)*+, -. Fe²⁺ Fe³⁺ /0

" 12.3 4 5  89À, ;<=>.  )*, ;? 6  89@A B C1 2 DEF(Fe²⁺ GH I Fe³⁺ G HJ)@AK LMN " +0 )*,6" OF P QR @A6 71 ST  U>" VW Q X>.  )*, Y8A" [Fe³⁺]=6.00Z10⁻⁷ M [>. Fe²⁺ ƒ„"  .3(~0.14 M HNO3

.Ûm -.)6 •8   - Fe²⁺

 ÀRK : ?$ ØK WR ¢">f, $

Q ^|j 1c Ârf Fe²⁺  Q ïxsm VF XSv>" -Ê   U>. “,

.3  © ™ 12~141c Âf Ô) Fe²⁺

 Fe³⁺sm  X ¶  U[>.

   

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