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Heterometric micro-determination of uranium (vi) by precipitation as phosphate
ANALYTICA
188
HI~TlXROMl~TRIC
CHIMICA
ACT.4
VOL.
11 (1951)
MICRO-T>ETERMINATION OF URANIUM(V1) l’RECIPITATION AS PHOSPHATE
RY
bY M.
13013TETL5I
ASD
MOIUL’CI-iAI
HAT~PERN
The aim of this work is to present a mctliod for the micro-cluantitativc precipimethod tation of ur:inium(VI) as phosl~hntc, taking advantage of a gravimctric without carrying out a separation and weighing. The hetcrometric method clcvcl01~x2 by tlic first author and co-workers, was used instead. Only a few milligrams of uranium (r-8 mg) in CL volume of x0 ml arc necessary, and the accuracy of detcrmination is about =L_0.01 mg. With some cspcricncc cvcn bcttcr results may he obtained. Gcncrally, a titration takes about 15 min. A scrics of cspcrimcnts was made and a sclcction of the results is given in tlrc form of curves (Figs. x and 2) and tables. (The table gives the numerical values of the cspcrimcnts, while the curves show the course of titration of the corrcspondtitrations showed that direct titration of U(W) ing cxpcrimcn ts). Preliminary results. (UOe(NO,),) with phosphate alone clots not give satisfactory
All details concerning the Hctcrometcr and hctcromctric titrations have lxrn given elscwlicrc l-‘. The chcmicnls used wcrc all c.1~. Uakcr analyscd reagents.
Titrations of uranium nitrate solutions with Na,HPO, in the prcscnce of NH&l gave no satisfactory results. Some titrations in the presence of NH&l are given in Fig. I, curves z and 3, and the calculations are compiled in Table I (cxp. x-3). The best results arc obtained in the presence of both NH,Cl and acetic acid. The presence of acetic acid raises the maximum optical density values (and hcncc sensitivity) and the accuracy. The addition of nlcohol decreases the mxximum density values and makes the results less certain. The titration proceeds quickly and readings on the galvanometcr become constant in a few seconds. The whole titration lasts less than 15 minutes. As experiment z (Table I and Fig. I, curve z) shows, theoretical values for uranium may be obtained. Rcfercmes
p.
xgr.
VOL.
0
11
HETEROMETRIC
(Xgj-#)
DETEI
URhPr’IUhI
1%)
Additional experiments were made with the purpose of increasing the scnsitivity of the hctcrometric titration towards smaller quantities of uranium. KHH,C1 was replaced by other basic nitrogen compounds. Hcxa?ttetltyLeltetctm?,tilLe and ctltylcwdin&m. Some results arc given in Table I (exps. 4 and 5). No advnntagcs could be obtained and an csccss of the rcagcnt (cthylenediaminc) intcrfcrcs with the results. I’yvidiltc. (See Table I, cxl~. 6 ancl 7. and curves 6 and 7). Tlic maximunl optical densities arc somcwllat higllcr than in the case of NE-I,Cl, thcrcforc somewhat smaller quantities of uranium may bc analysed. Tlic absolute error amounts to 0.01 mg for a solution of 0.00x:1/ uranium (tsp. 7). The tinic required for a full titration ~cncrally
I
0.e -
0.7 -
06-
incrcascs with the decreasing conccnuranium analysed. The tration of titration lasted (exp. 7) about half an hour. Quinolinc or qtrihzc. In the presence of quinine (exp. 8), even a solution of o.ooogM uranium could be analysed, but the time required was about 50 minutes. In the presence of quinolinc (exps. g-11) the maximum density is higher than with NH&l. A o.00~11 solution could be used and the errors were small or nil, but the time of titration was about 30-40 minutes. References
OF
p.
rgr.
Fig.
(Explanation
2
111text)
_.---.----
II
IO
9
8
7
G
j
4
3
2
I
Exper. number
Solution
COJlPOSITIOS:
___.___ __.
_._ -..--_--
3.00
?.Sjj7 0.004
3-05
I-15
a.90
2.95
2.95
3.00
2.9j
3.co
2.90
'$577 P5
7J-w
I ..#‘SS
d3j77
7.144”
7.144
7.r-w
7.r-t-t’
7.r-w
7J-G
o.ooq
0.01
0.002
0.004
0.01
0.01
0.01
0.01
0.01
0.01
f
0.004
0.004
0.01
0.00)
0.004
0.01
0.01
0.01
0.01
0.01
0.01
0.539
O.&
0.s2.I
0.292
0.392
0.629
0.37-t
0.233
0.26s
0.450
0.1sq
.
_
0.0
0.0
j
12
- - - - - -- --
$0.0 j
i-O.12
5
IO
12
I.2
0.0
12
0.0
2j
error 7 per ml
--O.Oj
---o.I
4.12
4.12
0.0
--0.11
0.0
4.2j
rug
Sa,HPO,.
Density masini.
s IId Illall
Xa:HPO, used ml molar ---_ _-_-_._
SOLUTIOX
UO,(FO,), Uranium in mg molar.
3 ml n;\l UOB(~Os), -+- 7 ml
ml 1~11CHJOOH + z ml IM XH,Cl + 4 ml alcohol I ml IM CH,COOH $zml rnif NH&I _t 4 ml H,O 2 ml IM NH&l $5 ml l&O I ml IM CHJOOH j- 3 ml O.IM ethylenediam. $3 ml H,O 2 ml IM CHJOOH + 0.5 ml IM hexamethylened. + 4.5 ml H,O 2 ml IJ~ CH,COOH -l- 5 ml 0.2N pyridine 2 ml IM CH,COOH _t 5 ml 0.2M pyridine 2 ml IM CHJOOH +5ml O.IM quinine. HCl 2 ml IM CH,COOH + 0.5 ml 141 quinoline + 4.5 ml H,O 2 ml IM CH,COOH + 0.5 ml rM quinoline $- 4,j ml ale. 2 ml IN CHJOOH + 0.5 ml IM quinoline f 4.5 ml H,O I
GEKERAL
TABLE I
VOL.
11
(1954)
HETEROhIETRIC
DETERSfIX.~TION
OF
UR:\NIU%X
=9=
From the above, the following conclusions may bc drawn: a water solution which contains a few mg (r-8) of uranium in n volume of 10 ml may lx hctcrometrically titrated with an accuracy of 0.01 to o.oz mg. nIETlIOD To n solution which contains a few mg urnnium(V1) in a volume of IO ml, are addeclo.5 ml +I[ NH&l or dcfinitc quantities of pyriclinc, quinolinc or quinine. A few drops of conccntratccl acetic acid arc added (final concentration of free acetic acid should bc about o.rM). A stanclardised solution of O.OIJI c).oo_l:lll Na,l-11’0, is aclclcd drop by drop from a microburct, while the solution is stirrccl vigorously. The rendings of the galvnnomctcr arc txkcn when they bccomc constant. The first maximtm~ optical clcnsity point which corrcslxxicls to tlic cnclpoint is taken cithcr from a grqh (cnlnrgcd), by drawing ;L lmc tllrough the maxima values obtained, or dcrivccl from the numerical vnlucs near the mnsimum. \k’hcre the quantity of the analyscd metal is unl;nown, it is advisable to make IL prclimiand only then to nary rough hctcromctric titration. taking only ;L few points make the final titration. Special attention is given to the points near tlic maximum optical density.
A mcthocl is prescrltcd for ihc hcteromctric dcterJnlnntion of uranium(Vl) i-8 ii16 uraJliunl in io ml solution can titration with a solution 0f Na,HPO,. dctcrnlincd with an accuracy of 0.01 mg it1 ztbout I 5 minutes. The influcncc various nitrogen compounds and different worlclJlg contlitions were studied.
by bc of
Unc mtithodc est prds;cnt& pour la d6tcrmination h&tdroJn~triquc dc 1’uranJuJn (VI) par titration au moycn d’unc solution de Na,HI’O,. J-8 n-ig d’ura;i;;;fl,dl;; . . .. cnvlrorl. _ IO ml de solution pcuvcnt Otrc d@termin& cn 15 Jninutcs des cl&iv& azotBs ct dcs conditions dc travail ont &tb &tucli&cs. ZUSllMMENFASSUNG Eine Methodc zur hcterometrischcn 13estimJnung VUJ~ Uraliium(VI) clurch I -8 1ng Uranium lctjrlncn In Titration mit ciner Na,HPO, Lbsung wird gcbracht. IO ml Ldsung mit ciner Genauiglceit von 0.01 rng in ctwn is IMinutcn bestirnmt werden. Der Binfluss von verschiedcnen Sticlcstoffvcrbinclungcn uncl den anclcren Arbeitsbedingungerl wurden studicrt.
1 M. BO~TELSI;Y 2 M.BOIATELSKY 76 1954) 1536. 3 M. h OL~TELSKY 4 M. BOESTELSKY 6 M. BOLSTELSKY 151, 156. 0 M. Boi3TELSKY 7 31. BOUTELSKY
AND ANU
I. BAR-GADDA, 13. GRAUS,
AND AND
13. GRAUS, Awrl. Chm. Acla. 9 (1953) JG~. I. BAR-GADDA, Ann!. Ciarvr. ACM, 9 (rg53) iG8, q.+G, 525. Y. \VEJ_WART, Awat. Cirrnr. Ada, 9 (1953) 281, 374; IO (1954).
AND
131~12.sot. ch~t~t.,(1953) 27G, 351, GH7, 8~9. CIbmL. sot. 30, 75 (1953) 4’72; Ihd.,
J. Am.
AND iM. Biir~isn, An&. Cirrrrr. .-1cf0, 10 AND J3. GRAUS, 23&l. Nes. Cul~nc. of IsY., Received
(1954)
260.
(1953)82. I)cccmber
1c:,tli,
I 953
188
HI~TlXROMl~TRIC
CHIMICA
ACT.4
VOL.
11 (1951)
MICRO-T>ETERMINATION OF URANIUM(V1) l’RECIPITATION AS PHOSPHATE
RY
bY M.
13013TETL5I
ASD
MOIUL’CI-iAI
HAT~PERN
The aim of this work is to present a mctliod for the micro-cluantitativc precipimethod tation of ur:inium(VI) as phosl~hntc, taking advantage of a gravimctric without carrying out a separation and weighing. The hetcrometric method clcvcl01~x2 by tlic first author and co-workers, was used instead. Only a few milligrams of uranium (r-8 mg) in CL volume of x0 ml arc necessary, and the accuracy of detcrmination is about =L_0.01 mg. With some cspcricncc cvcn bcttcr results may he obtained. Gcncrally, a titration takes about 15 min. A scrics of cspcrimcnts was made and a sclcction of the results is given in tlrc form of curves (Figs. x and 2) and tables. (The table gives the numerical values of the cspcrimcnts, while the curves show the course of titration of the corrcspondtitrations showed that direct titration of U(W) ing cxpcrimcn ts). Preliminary results. (UOe(NO,),) with phosphate alone clots not give satisfactory
All details concerning the Hctcrometcr and hctcromctric titrations have lxrn given elscwlicrc l-‘. The chcmicnls used wcrc all c.1~. Uakcr analyscd reagents.
Titrations of uranium nitrate solutions with Na,HPO, in the prcscnce of NH&l gave no satisfactory results. Some titrations in the presence of NH&l are given in Fig. I, curves z and 3, and the calculations are compiled in Table I (cxp. x-3). The best results arc obtained in the presence of both NH,Cl and acetic acid. The presence of acetic acid raises the maximum optical density values (and hcncc sensitivity) and the accuracy. The addition of nlcohol decreases the mxximum density values and makes the results less certain. The titration proceeds quickly and readings on the galvanometcr become constant in a few seconds. The whole titration lasts less than 15 minutes. As experiment z (Table I and Fig. I, curve z) shows, theoretical values for uranium may be obtained. Rcfercmes
p.
xgr.
VOL.
0
11
HETEROMETRIC
(Xgj-#)
DETEI
URhPr’IUhI
1%)
Additional experiments were made with the purpose of increasing the scnsitivity of the hctcrometric titration towards smaller quantities of uranium. KHH,C1 was replaced by other basic nitrogen compounds. Hcxa?ttetltyLeltetctm?,tilLe and ctltylcwdin&m. Some results arc given in Table I (exps. 4 and 5). No advnntagcs could be obtained and an csccss of the rcagcnt (cthylenediaminc) intcrfcrcs with the results. I’yvidiltc. (See Table I, cxl~. 6 ancl 7. and curves 6 and 7). Tlic maximunl optical densities arc somcwllat higllcr than in the case of NE-I,Cl, thcrcforc somewhat smaller quantities of uranium may bc analysed. Tlic absolute error amounts to 0.01 mg for a solution of 0.00x:1/ uranium (tsp. 7). The tinic required for a full titration ~cncrally
I
0.e -
0.7 -
06-
incrcascs with the decreasing conccnuranium analysed. The tration of titration lasted (exp. 7) about half an hour. Quinolinc or qtrihzc. In the presence of quinine (exp. 8), even a solution of o.ooogM uranium could be analysed, but the time required was about 50 minutes. In the presence of quinolinc (exps. g-11) the maximum density is higher than with NH&l. A o.00~11 solution could be used and the errors were small or nil, but the time of titration was about 30-40 minutes. References
OF
p.
rgr.
Fig.
(Explanation
2
111text)
_.---.----
II
IO
9
8
7
G
j
4
3
2
I
Exper. number
Solution
COJlPOSITIOS:
___.___ __.
_._ -..--_--
3.00
?.Sjj7 0.004
3-05
I-15
a.90
2.95
2.95
3.00
2.9j
3.co
2.90
'$577 P5
7J-w
I ..#‘SS
d3j77
7.144”
7.144
7.r-w
7.r-t-t’
7.r-w
7J-G
o.ooq
0.01
0.002
0.004
0.01
0.01
0.01
0.01
0.01
0.01
f
0.004
0.004
0.01
0.00)
0.004
0.01
0.01
0.01
0.01
0.01
0.01
0.539
O.&
0.s2.I
0.292
0.392
0.629
0.37-t
0.233
0.26s
0.450
0.1sq
.
_
0.0
0.0
j
12
- - - - - -- --
$0.0 j
i-O.12
5
IO
12
I.2
0.0
12
0.0
2j
error 7 per ml
--O.Oj
---o.I
4.12
4.12
0.0
--0.11
0.0
4.2j
rug
Sa,HPO,.
Density masini.
s IId Illall
Xa:HPO, used ml molar ---_ _-_-_._
SOLUTIOX
UO,(FO,), Uranium in mg molar.
3 ml n;\l UOB(~Os), -+- 7 ml
ml 1~11CHJOOH + z ml IM XH,Cl + 4 ml alcohol I ml IM CH,COOH $zml rnif NH&I _t 4 ml H,O 2 ml IM NH&l $5 ml l&O I ml IM CHJOOH j- 3 ml O.IM ethylenediam. $3 ml H,O 2 ml IM CHJOOH + 0.5 ml IM hexamethylened. + 4.5 ml H,O 2 ml IJ~ CH,COOH -l- 5 ml 0.2N pyridine 2 ml IM CH,COOH _t 5 ml 0.2M pyridine 2 ml IM CHJOOH +5ml O.IM quinine. HCl 2 ml IM CH,COOH + 0.5 ml 141 quinoline + 4.5 ml H,O 2 ml IM CH,COOH + 0.5 ml rM quinoline $- 4,j ml ale. 2 ml IN CHJOOH + 0.5 ml IM quinoline f 4.5 ml H,O I
GEKERAL
TABLE I
VOL.
11
(1954)
HETEROhIETRIC
DETERSfIX.~TION
OF
UR:\NIU%X
=9=
From the above, the following conclusions may bc drawn: a water solution which contains a few mg (r-8) of uranium in n volume of 10 ml may lx hctcrometrically titrated with an accuracy of 0.01 to o.oz mg. nIETlIOD To n solution which contains a few mg urnnium(V1) in a volume of IO ml, are addeclo.5 ml +I[ NH&l or dcfinitc quantities of pyriclinc, quinolinc or quinine. A few drops of conccntratccl acetic acid arc added (final concentration of free acetic acid should bc about o.rM). A stanclardised solution of O.OIJI c).oo_l:lll Na,l-11’0, is aclclcd drop by drop from a microburct, while the solution is stirrccl vigorously. The rendings of the galvnnomctcr arc txkcn when they bccomc constant. The first maximtm~ optical clcnsity point which corrcslxxicls to tlic cnclpoint is taken cithcr from a grqh (cnlnrgcd), by drawing ;L lmc tllrough the maxima values obtained, or dcrivccl from the numerical vnlucs near the mnsimum. \k’hcre the quantity of the analyscd metal is unl;nown, it is advisable to make IL prclimiand only then to nary rough hctcromctric titration. taking only ;L few points make the final titration. Special attention is given to the points near tlic maximum optical density.
A mcthocl is prescrltcd for ihc hcteromctric dcterJnlnntion of uranium(Vl) i-8 ii16 uraJliunl in io ml solution can titration with a solution 0f Na,HPO,. dctcrnlincd with an accuracy of 0.01 mg it1 ztbout I 5 minutes. The influcncc various nitrogen compounds and different worlclJlg contlitions were studied.
by bc of
Unc mtithodc est prds;cnt& pour la d6tcrmination h&tdroJn~triquc dc 1’uranJuJn (VI) par titration au moycn d’unc solution de Na,HI’O,. J-8 n-ig d’ura;i;;;fl,dl;; . . .. cnvlrorl. _ IO ml de solution pcuvcnt Otrc d@termin& cn 15 Jninutcs des cl&iv& azotBs ct dcs conditions dc travail ont &tb &tucli&cs. ZUSllMMENFASSUNG Eine Methodc zur hcterometrischcn 13estimJnung VUJ~ Uraliium(VI) clurch I -8 1ng Uranium lctjrlncn In Titration mit ciner Na,HPO, Lbsung wird gcbracht. IO ml Ldsung mit ciner Genauiglceit von 0.01 rng in ctwn is IMinutcn bestirnmt werden. Der Binfluss von verschiedcnen Sticlcstoffvcrbinclungcn uncl den anclcren Arbeitsbedingungerl wurden studicrt.
1 M. BO~TELSI;Y 2 M.BOIATELSKY 76 1954) 1536. 3 M. h OL~TELSKY 4 M. BOESTELSKY 6 M. BOLSTELSKY 151, 156. 0 M. Boi3TELSKY 7 31. BOUTELSKY
AND ANU
I. BAR-GADDA, 13. GRAUS,
AND AND
13. GRAUS, Awrl. Chm. Acla. 9 (1953) JG~. I. BAR-GADDA, Ann!. Ciarvr. ACM, 9 (rg53) iG8, q.+G, 525. Y. \VEJ_WART, Awat. Cirrnr. Ada, 9 (1953) 281, 374; IO (1954).
AND
131~12.sot. ch~t~t.,(1953) 27G, 351, GH7, 8~9. CIbmL. sot. 30, 75 (1953) 4’72; Ihd.,
J. Am.
AND iM. Biir~isn, An&. Cirrrrr. .-1cf0, 10 AND J3. GRAUS, 23&l. Nes. Cul~nc. of IsY., Received
(1954)
260.
(1953)82. I)cccmber
1c:,tli,
I 953