cevadine and veratridine, into a single slight overlap of fraction, P6,i,& vanilloylveracevine into P6.7,8 occurred, as well as some of the cevadine into PA4,s. However, this preliminary separation facilitated determination of the minor constituents. Preliminary separations vould not be required if all constituents occurred a t the same approximate concentration or if one were interested in only the major constituents. The distributions obtained with samples of the plate combinations from sample B after the eight transfer preliminary separation are shown in Figures 1 to 4. As noted by inspection, the components of P3,4.5 and P6,7,8 could readily be separated in a single distribution. With sample A, countercurrent distributions \yere made a t three p H values, whereas with sample B it was possible t o separate
x
all but the most hydrophilic constituents of P0,1,,with one distribution, using a larger number of transfers. The hydrophilic fraction was collected and redistributed a t a second pH, as shown in Figures 3 and 4. The difference betn-een the analyses shown in Table I1 and unity undoubtedly depends upon the evistence of a number of additional alkaloidal components. Determination and separation of these T o d d involve concentrates from large amounts of veratrine and more exacting countercurrent resolution. LITERATURE CITED
(1) Suterhoff, H., d r c h . Pharm. 286, 69
(1953). (2) Craig, L. C., Craig, D., “Technique of Organic Chemistry,” Vol. 111, Part 1, 2nd ed., A. Weissberger, Ed., Interscience,. Ken- York, 1956. (3) Hennig, 4. I., Higuchi, T., Parks,
I,. &I., J . Am. Pharin. AMOC., S a .
Ed. 40,168 (1951). (4) Kupchan, 11.K., Lavie, D., Delin-ala, C. B.,bndoh, B. T.rl., J . -4m.Chem. SOC.75 5519 (1953). ( 5 ) Pllacek, K., T’anecek, S., Pelcova, V., Vejdelek, 2. J., Chenz. Lzsty 50, 598 (1956). (6) Macek, K., 1-anecek, S., Vejdelek, Z. J., Zbzd., 49, 539 (1955). ( 7 ) PlIitchner. H.. Ph.D. thesis. rniversitr of Wisconsin School of Pharmacy, 1956. (8) Stuart, D. AI., Parks, L. M.,J . Am. Pharm. Assoc., Sei. Ed. 45, 252 (1956). (9) Vejdelek, Z. J., Macek, Ii., Iiakac, B., Chem. Listy 49, 1538 (1955). RECEIVEDfor reriev June 6, 1962. Accepted September 10, 196%. Kork supported in part by the Research Committee of the University of Wisconsin from funds supplied by the Kisconsin Alumni Research Foundation. .Zbstracted in part from a thesis submitted by G. R.Svoboda to the Graduate School of the University of Kisconsin in partial fulfillment of the requirements for the degree of dortor of philosophy. \
z
Separation of Metals by Cation Exchange in Acetone-Wa ter-Hyd rochloric Acid JAMES S. FRITZ and THOMAS A. RETTIG, Institute for Atomic Research and Department of Chemistry, Iowa State University, Ames, Iowa
b Distribution coefficients have been measured for the partition of metal ions between cation exchange resin and acetone-water-hydrochloric acid solutions. The differences in distribution coefficients of metal ions are greater in acetone-water media than in aqueous media of the same hydrochloric acid concentration. By using disiribution coefficient data, conditions for column separations of mixtures can be effected b y eluting with acetone-water-hydrochloric acid sohtions of different compositions. Successful separations of a number of mixtures are reported.
T
HE SEPARATION of metal ions as halogen complexes by elution from a cation exchange column with a n aqueous hydrohalic acid solution is now an established analytical technique. Fritz, Garralda, and Karraker (8) separated many metal ions using 0.1JI or 1JI hydrofluoric acid as the eluting agent. Yoshimo and Kojima ($2) and Strelow (17)separated cadmium(I1) from zinc(I1) and other metal ions b y elution with 0.5M hydrochloric acid. Fritz and Garralda (7) separated mercury(II), bismuth(III), cadmium(II), and lead(I1) from each other
1562
ANALYTICAL CHEMISTRY
and from other metal ions using 0.1 to 0.6M hydrobromic acid as the eluting agent. The extensive distribution coefficients of metal cations a t various concentrations of hydrochloric acid measured by Strelow (18) and b y Mann and Swanson (14) are a useful guide t o possible cation exchange separations in aqueous solution. It has been shown that metal ions are taken up more strongly and a t lower hydrochloric acid concentrations by an anion exchange column if an appreciable amount of a water-miscible organic solvent is added to the aqueous hydrochloric acid (10, 21). This behavior indicated the possibility of using a nonaqueous solvent to promote metal-halide complex formation for the selective elution of metal ions from a cation exchange column. Preliminary work by Pietrzyk (15) indicated that acetone is the most effective of the solvents tested. Buznea, Constantinescu, and Topar (8) and Ionescu, Segoescu, and Gainin (11) have effected the separation of copper(I1) and zinc(l1) on phenol formaldehyde-type cation exchange resin using acetone-water-hydrochloric acid solutions as eluting agents. Kember, Macdonald, and Kells have studied the behavior of several metals on Zeo
Karb 225, cation exchange resin using acetone-mater-hydrochloric acid eluants, but were able to separate only copper(I1) and nickel(I1) successfully (12). Van Erkelens has studied the ion exchange separation of complex mixtures of metal cations and anions in radiochemical amounts using acetonewater-hydrochloric acid solutions as eluting agents. He observed that certain separations. such as cobalt(I1)nianganese(I1) and iron(II1)-copper(I1)-zinc(I1) could not be effected, and that the addition of potassium iodide is necessary to effect the separation of copper(I1)-cobalt(I1) mixtures (90). I n the present aork. these mixtures are separated quite eacily, and many other separations either have been accomplished or are suggested hy the di-tribution coefficient data. EXPERIMENTAL
Reagents, Solutions, and Apparatus. CATIONEXCHAXGE R E ~ I N .Dowex50Q7 X8 analyzed reagent resin. 100- to 200-niesh, is used in t h e measurement of distribution coefficients and column separations. Before use, t h e rebin must be purified. Place the resin in a large column and backwash with distilled water to remove the fine particles. Then wash the resin
with 10ccamnionium citrate, 3-11 hydrochloric acid. and finally distilled water until a negative chloride test is obtained n i t h silver nitrate. Remove the excess x j t e r by suction filtration. K a s h the resin with absolute alcohol, then n i t h acetone, and allow it to dry. The air-dried resin has a water content of 15 to 207c b y neight. EDT-1 [DISODIUMDIHYDROGESE T H T L E S E D I X T R I L O ) TETRA.kCET.4TE DIHYI)RATE]. Prepare 0.05-11 and 0.00531
solutioni from analyzed reagent grade salt. Standardize by titration of zinc (11) from primary standard zinc metal. Naphthyl Aizoxine S (SilS) indicator is recommended ( 6 ) . METALSALTS.Prepare 0.05V solutions of metal perchlorates by dissolving primary standard metal in perchloric acid. If the metal is not available as a primary standard, dissolve reagent grade metal perchlorates or nitrates. Xitric acid is added t o bismuth solutions to prevent hydrolysis.
Analytical Procedures-EDTA
Titrations
Titration Buffer Metal method PH BiL3 Direct 2 5 Chloroacetate Ca+2 Direct 10 NH,0H-NH4C1 Cd+? Direct 5 5 Pyridine 5 5 Pyridine Co-* Direct 5.5 Piridine :u+2 Direct Fe-3 Spectrophoto2 5 Chloroacetate metrically Ga+3 Bark fCu+i) 5 . 5 Pvridine In+3 Back ( C u + ? ) 5 5 Pyridine Mg-2 Direct 10 SH40H-NH4CI Mn+2 Direct 10 NH40H--NH4C1 Xi+* Direct 5 . 5 Pyridine V 0 ~ 2 Direct 5 5 Pyridine Zn+Z Direct 5 . 5 Piridine LO,-? is titrated with ceric sulfate after reduction in a anthroline as indicator ( 1 6 ) . ~
dryness, and determine the metal ion content by an appropriate analytical method as listed above. Determine ."CETOSE - TYATER - HYDROCHLORIC accurately the water content of the ACID SOLUTIOSQ.The solutions are resin by oven-drying a sample of prepared so that the amount of organic known weight, and calculate the dissolvent and water is expressed as tribution coefficients on a dry weight per cent by volume and the hydrochloric basis. Calculate the distribution coeffiacid concentration as molarity. For cient with the follon-ing relation: wample, 1 liter of 0 . 5 Y hydrochloric acid in 70% acetone is prepared as mmoles of metal ion on resin follom: l l i u together 700 ml. of aceof dry resin D = nimolesgram tone, 41.5 ml. of concentrated hydroof metal ion in solution chloric acid, and 258.5 ml. of distilled total volume of solution water Volume changes due to miving are disregarded. Separation of Mixtures. Prepare t h e ion exchange column b y making IONESCHLXGE COLUMNS.Conventional 12-mm. i d . ion exchange columns a slurry of the resin a n d t h e first are fitted with Teflon needle valve eluting agent. Pour t h e slurry into stoppers to proi ide a more reproducible a 1.2-cm. i.d. column and let settle t o a height of 12.5 cni. Pass 10 nil. flow rate. Ai 60" glass funnel is fitted of t h e first eluting agent through t h e to the top of the column with a rubber column a t maximum flow rate t o stopper The entire volume of the equilibrate the resin with t h e eluting eluting agent is placed in the funnel a t agent. the beginning of the elution. Prepare a sample by pipetting into a M e a s u r e m e n t s of Distribution 10-ml. beaker known amounts of standCoefficients. TT'eigh accurately apard metal salt solutions. Carefully proviniately 1 gram of air-dried cation exchange resin into a 125-nil. glasqevaporate the sample mixture t o a stoppered Erlenmeyer flask. Pipet volume of 1 to 2 ml. and dilute with 10 ml. of 50% acetone. Concentrated into t h e flask 4 nil. of O.05M metal salt qolution and 50 ml. of the apnitric acid may be added during the propriate acetone-witer-hydrochloric evaporation to prevent salt hydrolysis. Transfer the sample t o the column, acid mixture. Stopper t h e flask and rinsing the beaker several times with shake for 24 hours. Pipet a n aliquot from the supernatant liquid, evaporate 1-ml, portions of the first eluting agent. After the sample has been rinsed onto the acid and organic solvent to near
Indicator Xvlenol Orange Ekio Black T U NAS Kaphthyl azoxine NAS Sulfosalicylic acid
Ref. 113) (1)' (6) (9)
(6) (19)
NhS 16) XAS (6) Erio Black T (1) Erio Black T NAS N AS X.4S (6) lead reductor, using 1.10-phen-
the column, attach a 60" funnel to the top of the column with a rubber stopper. Fill the funnel with the amount of eluting agent required to elute the first ion and adjust the flow rate to 0.3 to 0.5 ml. per minute. Evaporate the excess acid and organic solvent from the effluent fractions collected. Determine the amounts of metal salt present by an appropriate titrimetric procedure. RESULTS AND DISCUSSION
Distribution Coefficients. hleasurements of t h e batch distribution coefficient (D)offers a systematic method of choosing elution conditions, eliminating t h e necessity of trial and error selection. Although the distribution coefficient is measured on a batch basis, i t may be used to predict the elution behavior of metals on a n ion exchange column. T o separate two metals, the elution conditions are chosen such that one of the metals has a very high distribution coefficient and will thus be strongly retained b y the column. The distribution coefficient of the other metal should be very low (near one or less) so that the metal ion may be eluted with a small volume of eluting agent. The effect of the acetone upon the
Table I. Table of Distribution Coefficients- 0.5M Hydrochloric Acid
Ion 0 Bi'3 Ca + ? Cd+2 8 02 Co + 2 C U + ~ 88 Fet3 Ga+3 1n ~3 hlg +r &In+* 105
Ni + Z CO;z+' Zn
vo + 2
85 2
0
19 0
28 0
7 29
4 60
3 32
9
88
119 94 5
96
92
110
119
96
98
37 0
13 263
Acetone, yo 47 56 0 0 0
340 185 400 299 1790 4360 1 66 0 150
273 210 173 35 7 162
0 478 193 134 1870 45 0 08
330
251 197
11 1
131
461 407 180 0 92 165
65 0 0 591 136
15 4 48 8 0
551
708 197 0 167
74 0 0 558 41 0 0 6 67 0
174 730 61 0 163
84 0 90 0 106 3 50
86
87
102
91
82 174
108
89 106
0
0 0
83 290 708 3 30 0
81 7
96 37 7
151
VOL. 34, NO. 12, NOVEMBER 1962
1563
0 I' 3
I 40
1 50
" 60
I 70
I BO
-
100
90
- BO
50 60 " 70 PER CENT ACETONE
40
I
Figure 2. Distribution coefficients of bisrnuth(ll1) and cadrnium(1l)
PERCENT ACETONE
Figure 1. Distribution coefficients as a function of acetone concentration in 0.5M HCI
distribution coefficient may be seen in Figures 1 and 2 and Tables I and 11. The distribution coefficients of all metal ions studied increase with increasing proportions of acetone a t low percentages of acetone. A t higher percentages of acetone, however, the distribution coefficient of many metal ions drops sharply. The large decrease in distribution coefficient a t high acetone percentages is attributed to the forniation of chloro complexes which are held less strongly by the resin. Wickel(I1) and vanadium(1V) do not exhibit a decrease in distribution coefficient in 0.511 hydrochloric acid, indicating that complexation is not important a t this acid concentration. The distribution coefficients of nickel(I1) and manganese(I1) decrease a t high acetone
Table 11.
37
Cat2 c o+2
47.4
64.0
83.0
49
63 66.2
87.6 119
Bi + 3 Cd + 2 1n + 3
0
16.1 15.4
0
distribution coefficient at high acetone concentrations may be due to a solvent partition phenomenon. A comparison of the values of the distribution coefficients in aqueous 0.5M hydrochloric acid reported by Strelow (18) and those reported here in varying per cent acetone-0.5.M hydrochloric acid s h o w that the acetone has the effect of enhancing the differences in distribution coefficients of many metal ions. This enhancement of differences in distribution coefficients is used as the basis of separation of mixtures. Separation of Mixtures. I n the present work, batch distribution coefficients are used as guides to the
Table of Distribution Coefficients
Ion
60
concentration in 1. O M hydrochloric acid, illustrating the importance of acid concentration with regard to complexation. The effect of the eluent anion upon the distribution coefficient of copper(I1) may be seen in Figure 3. The curve of 0.5N hydrochloric acid media shows a decrease in distribution coefficient a t about 65% acetone. This decrease is attributed to complexation. Yellow copper-chloro complexes are observed a t acetone concentrations greater then 85%. The curve for the 0.5X HC104acetone medium shows no decrease in distribution coefficient with increasing percentages of acetone. Thus, complexation by perchlorate ion is not important even a t high acetone concentrations. The continual rise of
5.02 12.0
92.0 112 135
0.3M HC1 0 0 1.03 0 7.82 1.85
49.0 75.7 151
73 0 51.0 12.6 94.7
131
52.2 4.13
,
10:
0 0 0
0 0 0
0 0
0 0
i 5
1
:
O
:
0.2M HC1 Bi + 3
Cd +z Bi + 3 Cd +a
1564
0 71
213 476
0
30.7 37.5 305
ANALYTICAL CHEMISTRY
0
7.35
0 0
0.l.k' HC1 0 0
132
26
0 0
0 0
ZL
'40
50
60 PER
7b CENT
60
ACETONE
1 90
Figure 3. Distribution coefficients of copper(l1) in 0.5M perchloric and in 0.5M hydrochloric acid
selection of conditions for column separations ( 3 ) . The volume required to elute a metal ion from a column agrees favorably with the volume predicted by distribution coefficient data. The actual volume of eluting agent required is often slightly larger than t h a t indicated by the distribution coefficients, owing to tailing, which is more a p t t o occur in partially nonaqueous media. The lolume of eluting agent, required to elute a metal ion from a column is alv-ay. determined by collecting fractions of effluent from a column and analyzing the fractions. Ah elution curve of a ~i\-coinponent mixture is shorrn in Figure 4. The evtent of tailing and total ~ o l u n i eof eluting agent required for each metal ion are obtained from this type of curve. T o separate two metal ions on a cation exchange column, a solvent composition and hydrochloric acid concentration are chosen such t h a t one metal will be rapidly eluted from the column (D should be low, preferably nile or less) while the other metal ion has a high D and is tightly held by the column. When several metal ions are to be separated from each other, successive elution conditions are chosen so that only one metal ion is eluted by each eluting agent. I n the prrsent work, the concentration of acetone in the acetone-wter mixture and the concentration of hydrochloric acid are the variables which determine the composition of the eluting agent. From the distribution coefficient data and actual separations that have b e m effected, the elution scheme is as follows: Bi+3 is eluted with 60% acetone-0.1X HCl; Cd+ with 70% acetone-0.22' HCI; I n + 3 with 40% acetone-0.531 HCl; Zn+2 with 70% acetone-0.5N HCl; Fe+3 with 80% acetone-0.5% HCI; C ' U + ~with 85% acetone-0.5M HC1; U O Z - ~with 85% acctone-0.5M HCI; Co+* with 9070 acetone-0.5M HCI; G a t 3 with 90% acetone-0.5h' HCI; with 92% acetone-].OM HCl; Ca+2, Mgt2, are eluted as a group with aqueous 3 N hydrochloric acid. VO+z is eluted with 0.3% HzO~-O.lMHC104. .I number of separations using this elution scheme are presented in Table 111. E r e n an 11-component misture !vas separated and analyzed quantitatively. I n addition to the separations reported in Table 111, the following mixtures were successfully separated and the individual metal ions titrated quantitatively: Zn+"Cu + 2 , C U + ~ - C O + ~ , Zn+"Cu+z-Co+2, FeL3-Cu+"Ni+2, CO-Lh-i+Z, Bi+3-Cd +Z Bi +3_Ni+Z Bi t3-Zn+2, Cd+"Zn+"lln+z, Cor" 1In +2, In+"Fe +3, Ga -I"VO +z, Fe +3CoALXi+*,and Bi+3-Cd+"VO+Z. The average recovery for all separations (96 individual analyses) was
BOZACETONE 0 5 Y HCl 120 ml.
1
,
EFFLUENT V O W Y E
Figure 4.
Table 111.
sOXGSONE 0 5 Y HCI 153 mi
1
92XICRCUE I Y nci Immi.
3 M HCl 225mi
P
Iml.)
Elution curve for a six-component mixture
Separation and Analysis of Synthetic Metal Ion Mixtures on Dowex50W-X8 100- to 200-Mesh, Hydrogen Form Resin
(Metals appear in the order of elution with the amount of mash solution included with the first eluted metal) Eluting Agent Cd+2-Zn+2 (12 5 X 1 2 cm.). Cd+2, 25 ml. 4oy0 Ab-0 5M HC1 Zn+2,25 ml. iOyoA-O.5M HC1 ?rIn+2-NiT-1(12.5 X 1 2 cm.) 51n+2,45 ml. 92% A-1M HC1 Ni+2, 35 ml. aqueous 3M HC1 Zn +LFe t 3-Cu + 2-Mn + LhTi + 2 112 5 X 1 2cm.I ZnL2,20'ml. 60% A-O 5M HCl Fe13, 20 ml. 70% A-0 51M HC1 15 ml. SOYo A-0 5 M HC1 C U + ~32 . ml. 80% -4-0 5M HC1 Mnt2, 40 ml. 927, A-1M HC1 30 ml. aqueous 331 HC1 Fef3-Al+3 (12 5 X 1 2 cm.) Fe-3, 35 ml. 80% A-0 8M HC1 A1+3,125 ml. aqueous 3-44 HC1 Co+2-Ni+2(12 5 x 1 . 2 cm.) C O + ~45, ml. 90% A-0 5M HC1 50 ml. aqueous 3M HC1 CoT2-Ni+2(12 5 X 1 2 cm.) C O + ~45, ml. 90% A-0 5M HC1 XiTz,50 ml. aqueous 3M HC1 Bi-3-Cd+z-Zn+z 112 5 X 1 2 cm I BiT325 ml. 60% A-0: l%f HC1 ' Cd+225 ml. 70Vo A-0 2111 HC1 Zn-2 30 ml. 70% il-0.5M HC1 FeA3-,llT3(12 5 X 1 . 2 cm.) Fe+345 ml. 60% A-O.5M HCl A1 + 3 200 ml. aqueous 3M HC1 FeT3-Al+a(12 5 X 1 . 2 cm.) Fe+3 45 ml. SOTo A-O.5M HC1 A1+3200 ml. aqueous 3M HC1 Bi+3-Cd72-ZnC2(12.5 X 1 . 2 cm.) Bi+3 25 ml. 60% A-O.1M HC1 Cd+2 25 ml. 70% A-O.2M HC1 Zn T 2 30 ml. 70% A-0.5M HC1 I n +3-Znt2-Mn+2 (12.5 X 1 . 2 cm.) In's 35 ml. 4070 A-0.5M HC1 Zn+225 ml. 70% A-0 5M HCl Mn+250 ml. 92% A-1M HCl In fLFe+3-Mn+Z-?;i+Z (12.5 X 1 . 2 cm.) I n + 325 ml. 40% A4-0.5iMHC1 Fe+328 ml. SOToA-O.5M HC1 ?rfn+250 ml. 92% A-1M HCl N i f 2 30 ml. aqueous 331 HCl
Taken, mmoles
Found, mmoles
Recovery,
0.2289 0.2023
0,2279 0.2013
99 6 99 5
0,2023 0,2124
0.2023 0 2118
100 0 99 8
0,05036
0.05086
101 0
0.2019 0.09115 0.1012 0.1093
0.2009 0.09064 0.1012 0.1093
99 99 100 100
0.1883 0.1911
0.1873 0.1907
99 5 99 8
0.01974 0.2080
0,01969 0.2070
99 8 99 8
0.2098 0.2043
0.2090 0.2042
99 8 99 9
0.1788 0.2030 0.2035
0,1788 0.2024 0.2035
100 0 99 7 100 0
0.1878 0.1958
0.1863 0.1958
99 4 100 0
0.01732 0.1958
0.01727 0.1953
99 7 99 8
0.1787 0.2030 0.2035
0.2024 0.2035
0,1787
100 0 99 7 100 0
0.2216 0.2024 0.2009
0.2201 0.2024 0,2009
99 3 100 0 100 0
0.05540 0.1828 0.2009 0.2090
0.05540 0.1828 0.2009 0.2090
100 100 100 100
5%
5 5 0 0
0 0 0 0
(Continued o n page 1566)
VOL. 34, NO. 12, NOVEMBER 1962
1565
Table 111.
Zn+225 ml. 60c0,4-0 5111 HC1 Fe+3 25 ml. SOr, -4-0 5-11 HC1 C O +50 ~ ml. A-0 5111 HC1 Rln+z 50 ml. 92% A-131 HC1 Co+2-T'O+2-hln+2 (12 5 X 1 2 cm.) CoA250 ml. 9 0 5 A-0 531 HC1 VO+z 50 nil. 0 3cTc H?02-0 01112 HCIOa"15 ml H 2 0 Mn+2 50 ml. 92cc -4-0 5.11 HC1 Cd+2-Zn-?-Cu+2-Co-? 112 3 X 1 2 cn1.l Cd+225 ml 40", &A-0 532 HC1 Zn+Z 25 ml. 70rc d-0 3-11 HC1 CuT225 ml. 905; -1-0 5J1 HC1 Co+*40 ml. 90% h-1M HC1 I I I + ~ - A ~112.5 + ~ X 1 . 2 cm.l In+3 25 ml. 40% A-0 5M HCl A P 3 150 ml aqueous 351 HC1 Inf3-hln+* (12 5 X 1 2 cm.) Int3 25 nil. 409; AA-O 5-11 HC1 M n + 2 50 ml. 92% .4-0.5.11 HC1
Xii2 60 ml. aqueous 332 HC1 Bi+3-Cd+2-Zn+2(16.0 X 1 . 2 cm.) Fe +LCU+?-Co t 2 -
(Continued)
Taken, mmoles
Found, mmoles
Recover),
0,2035 0.1883 0.2085
0.2035 0.1878 0.2085
100 0
0.2009
0.2009
100 0 100 0
0.2074
0.2074
100 0
0.1226 0,1995
0.1221 0.1995
99 6 100 0
0,2290 0,2028 0.2335 0.1958
0.2280
0.2023 0.2339 0.1948
99 0 99 8 100 2 99 5
0.1938 0.1798
0,1934 0.1793
99 8 99 7
0.1938 0.2001
0,1934
Y9 8
0.2000
90 7
0.1938 0.1891 0.2078 0,2044
0.1933 0.1888 0.2068 0.2039
99 99 99 99
1566
ANALYTICAL CHEMISTRY
99 7
7 8 5
8 LITERATURE CITED
VO-2-Mn +2-A1 + 3 Ni +2-'17 + 3 0,09971 Bi-3 35 nil. 60% -1-0 5J2 HC1 0.09527 CdT230 ml. 40% A-0 5J2 HC1 0,09971 Zn'? 35 ml. 60% A-0 5-12 HCl 0.09191 F e f 3 30 ml. 70% A-0 5%' HCl 30 ml. 80% -4-0 5-11 HC1 0.09230 C u f 2 55 mi. 80C, 'A-0 53f HC1 0,1042 Co+*65 ml. 905; -4-0 5J1 HC1 VO +? 35 ml. 0.3(', H202-0 0 1 X 0.04543 HClOI 0.1002 M n A 2i 0 nil. 92cC A4-0 132 HC1 0.07792 L41+3200 ml. 0.1W HF 0.1032 NiT2200 ml. 1 5M H?rTO3 0,09527 Y+3 200 ml. 2 051 HNO, a Metal mixture (column dimensions). A = acetone. c Eluent passed through column at maximum flow rate.
slightly lorn (99.87,). The standard deviation for all data was 10.3%. The elution method for VO+2 is from studies by Fritz and Abbink (6). Copper(I1) is eluted with 85% acetone0.511 hydrochloric acid to permit If coseparation from cobalt(I1). balt(I1) is not present in the mixture, copper may be eluted more rapidly with 907, acetone-0.5-11 hydrochloric acid. Copper(I1) and cobalt(T1) cannot be separated by eluting copper(I1) with 90% acetone-0.5.11 hydrochloric acid. Vanadium(1V) must be eluted before manganese(I1) because vanadium is also eluted by 927, acetone-] . O X hydrochloric acid. The column is washed with a t least 15 ml. of water to remove excess acid before the peroxide eluent is added to elute vanadium(1V). This is
cr
hydrochloric acid. The elution of uranium(V1) with 90% acetone-131 hydrochloric acid is incomplete. A total volume of 50 ml. is required to elute cobalt with either eluting agent. Cadmium(I1) and manganese(I1) also tail, but not qeriouslg-. Tailing can be reduced by decreasing the flow rate; however, a convenient balance between flow rate and the time required to elute a metal ion must be found. A flow rate of 0.3 to 0.5 ml. per minute gives the most satisfactory results. Tailing can also be reduced by using a finer mesh resin, but this alternative has not been tried. I n the mixtures analyzed aboLe, the sample constituents are present in approximately equimolar amounts. The total amount of metal ions loaded onto the resin should not exceed 1.5 mey. for a column 12.5 cm. X 1.2 em. This maximum load represents a cation-resin ratio of 0.065. Heavier loading of the resin mill increase tailing. A high ratio of one or more sample constituents to another does not cause any difficulty as long as the column i q not overloaded (Tahle 111).
(1) Biedermann,
0.09920 0,09477
99 5 99 5
0,09971 0.09141
100 0 99 5
0,09206 0.1039
99 7 99 7
0.04393 0.09995 0 . 07792
0.1032 0.09501
95 99 100 100 99
6 8 0 0 7
done to minimize gas bubble formation in the column. The bubbles do not seriously affect the subsequent elution of metal ions through the column. Transformation from a partially nonaqueous elution medium to a n aqueous medium and then back to a partially nonaqueous medium does not hinder the performance of the column. Several separations are not possible using this scheme. Indium(II1) and cadmium(I1) can only be separated as a group. Aluminum(III), calcium(11), magnesium(II), nickel(II), and cobalt(I1) and gallium(II1) can be separated only as groups. Tailing is a problem in the elution of cobalt(I1) and uranium(V1). Cobalt is eluted with 90% acetone-0.5-$1 hydrochloric acid or 90% acetone-1 M
IT.,Schwarzenbach, G.
Chzmia Aarazc 2, 56 (1948). ( 2 ) Buznea, G., Constantinescu, O., Topar, D., Acad. Rep. Poptilare n o m i n e , S t u d i i Cercetari Chim. 6 , 333 (1958). (3) Cornish, F. W., Analyst 83,634 (1958). (4) Flaschka, H., Amin, A . PIT., Mtkrochirn. Acta 1953, 414. (5) Fritz, J. S.,Abbink, J. E., ANAL.CHEJI. 34, 1080 (19@2) (6) Fritz, J. S.,Abbink, J. E., Payne, hI. A , , AXAL.CHEM.33, 138 (1961). 171 Fritz. J. S..Garrslda. B. B.. Ibid., 34, 1387 (1962).
(8) Fritz, J. S.,Garralda, B. B., Karraker, S. K., Ibid., 33, 882 (1961). (9) Fritz, J. S.,Lane, 11'. J., Bystroff, rl. S.,Ibid., 29, 821 (1957). (10) Fritz. J. S.. Pietravk. D. J.. Talanta
( 1 l j Ionescu, P., Scgoescu, I., Gainin, I., Proc. U . Y . Intern. C o d . Peacefitl llses A t . Energy, 2nd, Oenevn, 20, 123 (1958). (12) Kember, N. F.. Xacdonald, P. S., Wells, R. 4.,J . Chem. Soc. 1955, 2273. (13) Korbl, J., Pribil, R.. Chernzst-Analyst 45, 102 (1956). (14) Mann, C. K., Swanson, C. L., AXAL. CHEM.33, 459 (1961). (15) Pietrzyk, D. J., Ph.D. thesis, Iowa State University, Ames, Iowa, 1961. (16) Sill, C. W., Peterson, H. E., AYAL. CHEM.24, 1175 (1952). (17) Strelow, F. W. E., Ibid., 32, 363 (19601. (18) Ibid., p. 1185. (19) Sweetser, P. R., Bricker, C. E., Ibid., 25, 253 (1953). (20) Van Erkelens, P. C., A n a l . Chim. A c t a 25, 42 (1961). (21) Wilkens, D. H., Smith, G. E., Talunta 8, 138 (1961). (22) Yoshimo, Y., Kojima, M.,Bunsekz Kagaku 4, 311 (1955). RECEIVEDfor review June 18, 1962 Accepted September 4, 1962. Contribution N o . 1161 from the Ames Laboratory of the U. S.Atomic Energy Commission.
