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Spectrophotometric determination of lanthanides and yttrium with diantipyrylazo
SHORTCOMMUNICATIONS
246 Spectrophotometric with diantipyrylazo
determination
of lanthanides
of chromotropic Many 2,7_bisphenylazo derivatives 1, Diantipyrylazo, chromogenic reagents in spectrophotometry azo)chromotropic acid (I) is the first known heterocyclic
\
and yttrium
acid have been used as i.e. 2,7-bis(4’-antipyryl2,7-bisazo derivative of
SO,H
H4S
chromotropic acid”. Its chromogenic properties differ very strongly from the analogous properties of the bisphcnylazo clcrivativcs. The interval of pn for spectrophotometric application of diantipyrylazo is 3-12. Diantipyrylaso is a selective photometric reagent for the determination of lanthanides and yttrium.
Adjust the acidity of the sample solution using 0.x fir hydrochloric acid and sodium hydroxide to pH 4-5 with methyl red as indicator. Place an aliquot of the sample solution, containing 0.05-0.4 ,umole of lanthanides and yttrium, in a 25ml volumetric flask. Add I ml of IO- 3 M potassium cyanide and 0.5 ml of x0-3 M ammonium fluoride and mix. Add 10.0 ml of aqueous I .o * 10-4&l diantipyrylazo solution (prepared by dissolution of 74.9 mg of the reagent in I 1 of water), dilute with water to the mark and mix. Measure the absorbance in I-cm cells at 645 rnp vs. a reagent blank. 0.1 M
If I
mmolc of uranium(W) is present in the sample aliquot, I ml of solution must be adclcd and uranium(V1) extracted with four xo-ml portions of acetylacetonc-chloroform(x : I), in each case by 2-3 min of vigorous shaking. The acidity conditions of the extraction are analogous to those above. The aqueous phase is evaporatecl to dryness and the residue is heated to 500-600~. Then the residue is dissolved in 3 ml of 0.1 M hydrochloric acid, the PH of solution is adjusted to 4-5 with 0.1 il.4 soclium hydroxide using methyl red as indicator, and the procedure given above is applied. The determination of lanthanides and yttrium in thorium is carried out as follows. The acidity of an aliquot of sample solution containing 0.1-200 pmole of thorium is adjusted to PH 1.0-x.5. The solution is extracted with four ro-ml portions of 0.5 M thenoyltrifluoroacetone in benzene, in each case by 3-5 min of vigorous shaking. The acidity of the aqueous phase is adjusted with 0.1 M sodium hydroxide to PH 4-5, and the determination is completed as described above. The net analytical molar absorptivities for individual lanthanides and yttrium on complex formation with diantipyrylazo are given in Table I. 0.1
Anat.
l
IO-L1.o
M disodium-EDTA
Chim.
Acta,
36
(1966)
246-248
SHORT COAIMUNICATIONS TABLE NRT
I
ANALYTICAL
MOLAR
AIJSORDTIVXTIES
_----.--____Y
Ntl Sm Eu(lll)
45,000 20,600 23,000 23,200 25,000 27,600
Ckl
348400
OF -._._.-.
--._
Foreigu iow added (pwaole)
Cu(l1)
0.10
0.15 0.10
Al
0.05 0.10 0.001
Ga In
_.
..-
Pb(II) V(V) Nb(V) Cr(KI1)
La Y Gtl
Fc(ILI)
I,;1
Pr
0.05 0.06 1.50
645 nip
AND
PI4
5.5
28.800
23.000 2 I .ooo
1-U
1.50 1.50
Yb
0.210
0.100
o.og8
0.200
0.212
0.100
0.099 0.105 0. I9G
0.200 0.200
0.210
0.200
0.226
o.roo
_.-_-_
--_ ._.-.-.-
0.100 0.200
0.204
0.100
Y
0.100 0.200
o.xgB
0.200
0.1g2
0.100
0.300 0.300 0.100
La
0.200
Gd Yb La
0.100
0.050 0.050 o.roo 0.100 0.x00
error (%I
0.208 0.098 o. x06 0.108 0.297 0.285 0.098 0.095
0.100
. ----.-..-
Relative
0.101
0.105 0.097 0.1oq
0.200
0.05 0.10
200.0
0.103
0.100
0.3 0.5 goo.0 900.0 500.0 100.0 150.0
--_-
0.200
1.50
0.1
- ._._
0.100
2.00
3.00 0.5
YTTRIUM
__._.._.
0.100
I.0
Thb
AT
33,500 3 I ,000 30.000 W,400
AND
0.100
2.00
U(VI) 0
IONS
Molnr absorp. (cmaf mmole) ~--
and yftrirrm Fowrd (prtrole) T akerz (pmole)
0.003
EDTA
METAL
Lanfhanidcs
0.002
Ni
iow
-_-.-.-.--.--I. Tb DY Ho ElTm Yb(III) LU
LANTHANIDES
0.20
Co(I1)
INDlVIDUAL
II
DETERMINATION .._-._ --._--
Mefal
2g,400
!;(I,,)
FOR
_---
Molar absorp. (cm~/mnroCe) ____.._ -.
Metal iolr
TABLE
247
0.190
0.098 0.051 o.o4g
0.103 0.102 0.x00
n Extraction of uranium(V1) with acctylncctone-chloroform b The extraction of thorium with TTA was applied.
wns appliccl. .4nal. Claim. Acfa, 36 (rgG6) 246-248
SHORT COMMUNICATIONS
248
The following amounts, in /Amole per 25 ml of solution, of other ions interfere: coppcr(I1) 0.15, scandium 0.10, aluminium 0.20, gallium 0.10, indium 0.10, thallium(II1) 0.10, titanium(IV) 0.10, zirconium 0.10, hafnium 0.19, ~crmanium(IV) 5.0, tin(I1) 0.10, leacl(l1) o.oG, vanadium(V) 2.0, niobium(V) 2.0. bismuth 0.2, chromium(III) 2.0, molybdenum(W) 0.2, tungstcn(V1) 0.2, magnanese(II) 2.0, iron(II1) 2.0, cobalt(I1) 1.0, nickel 0.1, palladium(I1) 2.0, thorium 0.1, uranium(VI) 0.06, fluoride 0.7, cyanide x.5, pllosphate 0.5. sulphate 1.0, EDT.4 0.5, citrate 0.0 and tartratc 0.G. The acpcous solutions of cliantipyrylazo are stable for some months. l’lic complcxcs of the rcngcnt with lanthanides and yttrium are stable in solution under normal conditions for IO 11. ‘I’hc deviations in the individual determinations do not cxccccl & 5% relative. The molar ratio between metal and ligancl in the complexes of lanthaniclcs is I : I. Some clxwactcristic results of analyses arc given in Table II. Nuclear Reseurclt Institzdc, Czeclroslovak Academy oJ’ Sciences, Rzlrezh may Prngzle (Czeclaoslova?zia)
(Rcceivcd
April
rst,
1966)
Aunl. Chirn. AC/n, 3G (rgGG)
The
Boedeker
240-243
reaction,
Part
III.
The
detection
of sulphite
ion
Nitroprussidc and sulphite ions in aqueous solution interact to givel-6 the red, hi&ly-dissociated sulphitonitroprusside ion, Fe(CN)sNOSOs+. The acldition of zinc ions results in the formation of sparingly soluble zinc sulphitonitroprusside, and markedly increases the sensitivity of the reactionllc. According to CHARLOI‘, xoo pp.“. of sulphite We
ion is cletectable have
observed
two
in aqueous new
aspects
solution
in this
of the Boedeker
way”. reaction.
First,
the amount
in solution is increased not only by the addition of zinc ions, but also by the addition of alkali metal ions”. This effect of alkali metal ions appears to be due to the formation of ion-pairs of the type Fe(CN)hNOS03M3--, where M is an alkali metal. The effect is more pronounced, the larger the alkali metal ion. Secondly, the sensitivity of the reaction involving zinc ion has been shown to be further improved by the addition of pyridine; this is believed to be due to the low solubility of (Zn pys)nFe(CN)s’NOS03. In the present communication the analytical aspects of the l3oedeker reaction are reassessed. A method is described by which 5 p.p.m. of sulphite ion in aqueous solution may be detected; interference by sulphide ion is avoided. of sulphitonitroprussicle
Asal.
ion formed
Chim. Acta, 36 (rg66) 248-251
246 Spectrophotometric with diantipyrylazo
determination
of lanthanides
of chromotropic Many 2,7_bisphenylazo derivatives 1, Diantipyrylazo, chromogenic reagents in spectrophotometry azo)chromotropic acid (I) is the first known heterocyclic
\
and yttrium
acid have been used as i.e. 2,7-bis(4’-antipyryl2,7-bisazo derivative of
SO,H
H4S
chromotropic acid”. Its chromogenic properties differ very strongly from the analogous properties of the bisphcnylazo clcrivativcs. The interval of pn for spectrophotometric application of diantipyrylazo is 3-12. Diantipyrylaso is a selective photometric reagent for the determination of lanthanides and yttrium.
Adjust the acidity of the sample solution using 0.x fir hydrochloric acid and sodium hydroxide to pH 4-5 with methyl red as indicator. Place an aliquot of the sample solution, containing 0.05-0.4 ,umole of lanthanides and yttrium, in a 25ml volumetric flask. Add I ml of IO- 3 M potassium cyanide and 0.5 ml of x0-3 M ammonium fluoride and mix. Add 10.0 ml of aqueous I .o * 10-4&l diantipyrylazo solution (prepared by dissolution of 74.9 mg of the reagent in I 1 of water), dilute with water to the mark and mix. Measure the absorbance in I-cm cells at 645 rnp vs. a reagent blank. 0.1 M
If I
mmolc of uranium(W) is present in the sample aliquot, I ml of solution must be adclcd and uranium(V1) extracted with four xo-ml portions of acetylacetonc-chloroform(x : I), in each case by 2-3 min of vigorous shaking. The acidity conditions of the extraction are analogous to those above. The aqueous phase is evaporatecl to dryness and the residue is heated to 500-600~. Then the residue is dissolved in 3 ml of 0.1 M hydrochloric acid, the PH of solution is adjusted to 4-5 with 0.1 il.4 soclium hydroxide using methyl red as indicator, and the procedure given above is applied. The determination of lanthanides and yttrium in thorium is carried out as follows. The acidity of an aliquot of sample solution containing 0.1-200 pmole of thorium is adjusted to PH 1.0-x.5. The solution is extracted with four ro-ml portions of 0.5 M thenoyltrifluoroacetone in benzene, in each case by 3-5 min of vigorous shaking. The acidity of the aqueous phase is adjusted with 0.1 M sodium hydroxide to PH 4-5, and the determination is completed as described above. The net analytical molar absorptivities for individual lanthanides and yttrium on complex formation with diantipyrylazo are given in Table I. 0.1
Anat.
l
IO-L1.o
M disodium-EDTA
Chim.
Acta,
36
(1966)
246-248
SHORT COAIMUNICATIONS TABLE NRT
I
ANALYTICAL
MOLAR
AIJSORDTIVXTIES
_----.--____Y
Ntl Sm Eu(lll)
45,000 20,600 23,000 23,200 25,000 27,600
Ckl
348400
OF -._._.-.
--._
Foreigu iow added (pwaole)
Cu(l1)
0.10
0.15 0.10
Al
0.05 0.10 0.001
Ga In
_.
..-
Pb(II) V(V) Nb(V) Cr(KI1)
La Y Gtl
Fc(ILI)
I,;1
Pr
0.05 0.06 1.50
645 nip
AND
PI4
5.5
28.800
23.000 2 I .ooo
1-U
1.50 1.50
Yb
0.210
0.100
o.og8
0.200
0.212
0.100
0.099 0.105 0. I9G
0.200 0.200
0.210
0.200
0.226
o.roo
_.-_-_
--_ ._.-.-.-
0.100 0.200
0.204
0.100
Y
0.100 0.200
o.xgB
0.200
0.1g2
0.100
0.300 0.300 0.100
La
0.200
Gd Yb La
0.100
0.050 0.050 o.roo 0.100 0.x00
error (%I
0.208 0.098 o. x06 0.108 0.297 0.285 0.098 0.095
0.100
. ----.-..-
Relative
0.101
0.105 0.097 0.1oq
0.200
0.05 0.10
200.0
0.103
0.100
0.3 0.5 goo.0 900.0 500.0 100.0 150.0
--_-
0.200
1.50
0.1
- ._._
0.100
2.00
3.00 0.5
YTTRIUM
__._.._.
0.100
I.0
Thb
AT
33,500 3 I ,000 30.000 W,400
AND
0.100
2.00
U(VI) 0
IONS
Molnr absorp. (cmaf mmole) ~--
and yftrirrm Fowrd (prtrole) T akerz (pmole)
0.003
EDTA
METAL
Lanfhanidcs
0.002
Ni
iow
-_-.-.-.--.--I. Tb DY Ho ElTm Yb(III) LU
LANTHANIDES
0.20
Co(I1)
INDlVIDUAL
II
DETERMINATION .._-._ --._--
Mefal
2g,400
!;(I,,)
FOR
_---
Molar absorp. (cm~/mnroCe) ____.._ -.
Metal iolr
TABLE
247
0.190
0.098 0.051 o.o4g
0.103 0.102 0.x00
n Extraction of uranium(V1) with acctylncctone-chloroform b The extraction of thorium with TTA was applied.
wns appliccl. .4nal. Claim. Acfa, 36 (rgG6) 246-248
SHORT COMMUNICATIONS
248
The following amounts, in /Amole per 25 ml of solution, of other ions interfere: coppcr(I1) 0.15, scandium 0.10, aluminium 0.20, gallium 0.10, indium 0.10, thallium(II1) 0.10, titanium(IV) 0.10, zirconium 0.10, hafnium 0.19, ~crmanium(IV) 5.0, tin(I1) 0.10, leacl(l1) o.oG, vanadium(V) 2.0, niobium(V) 2.0. bismuth 0.2, chromium(III) 2.0, molybdenum(W) 0.2, tungstcn(V1) 0.2, magnanese(II) 2.0, iron(II1) 2.0, cobalt(I1) 1.0, nickel 0.1, palladium(I1) 2.0, thorium 0.1, uranium(VI) 0.06, fluoride 0.7, cyanide x.5, pllosphate 0.5. sulphate 1.0, EDT.4 0.5, citrate 0.0 and tartratc 0.G. The acpcous solutions of cliantipyrylazo are stable for some months. l’lic complcxcs of the rcngcnt with lanthanides and yttrium are stable in solution under normal conditions for IO 11. ‘I’hc deviations in the individual determinations do not cxccccl & 5% relative. The molar ratio between metal and ligancl in the complexes of lanthaniclcs is I : I. Some clxwactcristic results of analyses arc given in Table II. Nuclear Reseurclt Institzdc, Czeclroslovak Academy oJ’ Sciences, Rzlrezh may Prngzle (Czeclaoslova?zia)
(Rcceivcd
April
rst,
1966)
Aunl. Chirn. AC/n, 3G (rgGG)
The
Boedeker
240-243
reaction,
Part
III.
The
detection
of sulphite
ion
Nitroprussidc and sulphite ions in aqueous solution interact to givel-6 the red, hi&ly-dissociated sulphitonitroprusside ion, Fe(CN)sNOSOs+. The acldition of zinc ions results in the formation of sparingly soluble zinc sulphitonitroprusside, and markedly increases the sensitivity of the reactionllc. According to CHARLOI‘, xoo pp.“. of sulphite We
ion is cletectable have
observed
two
in aqueous new
aspects
solution
in this
of the Boedeker
way”. reaction.
First,
the amount
in solution is increased not only by the addition of zinc ions, but also by the addition of alkali metal ions”. This effect of alkali metal ions appears to be due to the formation of ion-pairs of the type Fe(CN)hNOS03M3--, where M is an alkali metal. The effect is more pronounced, the larger the alkali metal ion. Secondly, the sensitivity of the reaction involving zinc ion has been shown to be further improved by the addition of pyridine; this is believed to be due to the low solubility of (Zn pys)nFe(CN)s’NOS03. In the present communication the analytical aspects of the l3oedeker reaction are reassessed. A method is described by which 5 p.p.m. of sulphite ion in aqueous solution may be detected; interference by sulphide ion is avoided. of sulphitonitroprussicle
Asal.
ion formed
Chim. Acta, 36 (rg66) 248-251