an absorber is used. Yttrium-91 does not coextract to any appreciable extent as is evident from the comparison of the procedure with the ceric iodate method ( 2 ) shown in Table IT’. This method ib witahle for fiqsion producxt mixtures obtained :A% waste from p r o c r . k g pI:iiit\ or irr:ttlinted sample. from which actinides have been remorcrl hr rvtractioii from nitric acid (7, 1%’). Ten aliquots of cerium-144 tracer solution containing 3.5 x 106 c.p.m. were carried through the extraction procedure. The average yield for the 10 determinations was 91.2 =t 0.iyh Samples of a one-gear-old fission product mixture were analyzed for cerium by the extraction procedure described and by the ceric iodate precipitation method ( 2 ) . The results obtained by the two methods are given in the Table IV and agree to within 2% for every sample. Radiochemical purity of the separated cerium by this procedure was checked by gamma-ray spectrometry. Less than
1% of the activities present were due to fission products other than cerium. The precision of the method was chccked by carrying out 10 replicate. allalybP5 or1 one-year-old f i 4 o n product nii\tiiiw T h e ichtii htar~(l:rr~l cleiiatiori M :is & I .2%. Itesiclet spred and iinililic,ity, mi ndtlml xdv:tnt a g o~f the procctluie i, thc of rea(lilv :I! :iil:il)le solvrnt P . (A
ACKNOWLEDGMENT
The author is grateful to D. J. Carsne11 from the Department of Kuclear and Radiation Cheniiftry, University of S e w South Wales, for his many valuable suggestions and discussions on this paper. LITERATURE CITED
(1) Alcock, K., Grimley, S. S., Healy, T. V., McKav, H. A. C., Trans. Faradazi SOC.
52,
39 (iS56).
W. F.. Hume. D. Xi.. “Radiochj,mical Studies. The Fission Products, C. D. Coryell, 5 . Sugarman, eds., Vol. 9, p. 1693, hfcGrawHill, New York, 1951.
121 Boldridee. \
I
(3) Butler, T. A , , Ketchen, E. E., Ind. Eng. Chenz. 53, 651 (1961). (4) Fionaeus, Y.,Ostman, O., .lcfu. r h e i n . Scand. 10, 769 (1956). (5) Glendenin, I,. E., Flyiln, K. B’., Buchanit11, It. F., Steiuberg, E. l’., , A U A I ~ (’IIEM 27, 59; J lO55). (6) IIaitIwic~l,, I . .I., Itulm-ts~m,1 2 , ( ‘ ( i t ) .
.r. m,)tz. 29, xi8 ( i
~1.
i
( 7 ) f I ( J M t d Y l G . H., IIllghPS, ‘r. ci., RIackey, G. It., Saddington, IC., l’/:W, International Conference of Penref 111 Uses of Atomic Energy, Geneva, 1 %S. ( 8 ) Heal?-, T. V., J . Inorg. ,\’ucl. Chem. 19, 314 (1961). ( 9 ) Irving, H., Edgington, D. S . , I M . , 15, 158 (1960). ( l a ) Marsh, S. F., Maeck, W.J., Booman, G. L.. Rein, J. E., ANAL. CHEK 34.
1406 (1962).’
(11) McCown, J. J., Larsen, R. P., Ibid., 3 2 . 597 (1960). \ - - - - ,
(12jkairn, J. S., Collins, D. .4.,McKay, H. A. C., Maddock, A. G., P/1458, International Conference on Peaceful Uses of Atomic Energy, Geneva, 1958. (13) Smith, G. W., Moore. F. L. ANAL. CHERI.29, 448 (1957). RECEIVEDfor review January 9, 1963. Accepted Sugust 7 , 1963.
Fast Paper Chromatography of Different Valence States of Mercury and Antimony MOHSIN QURESHI and MUKHTAR A. KHAN Prince of Wales Chemical Laboratories, Deparfmenf of Chemistry, Aligarh Muslim University, Aligarh, India
b A decrease in the separation time of metals in differing valence states is effected by use of a suitable solvent system. A number of solvent systems are studied for the separation of Hg;’-Hg’’ and Sb+3-Sb’5. The most selective separation of Hgi2Hg’a is obtained with a mixture of HN03-HCI-isopropanol; Sb’3-Sb’5 separations are efficient in a mixture of acetic acid-water-ethyl acetate. I?, values are given for ions which are likely to interfere in the procedure, and the phenomenon of double spots is discussed.
T
of separation is a particularly important factor in the paper chromatographic separation of a metal in different valence states. If the separation time is long enough, some interconversion of valence state may occur. Also, one of the valence statesSb+5 in the present case-may be sufficiently reactive to interact slowly with the paper or the solvent system. Several techniques may be utilized to decrease the separation time, including the use of a higher temperature, centrifugal chromatography, or choice of a proper solvent system. A higher temperature may inrrease the rate of HE TIME
2050 *
ANALYTICAL CHEMISTRY
interconversion, as well as decrease the separation time, and centrifngal chromatography requires specialized equipment. Therefore, the choice of a proper solvent system offers the simplest solution t o the problem. The importance of the study of such separations has been discussed previously (1-3). -4 fast solvent system (3) was reported for the separation of Fe+2 and Fe+3. This paper summarizes recent findings on the separation of different valence states of Hg and Sb. These separations were reported earlier by Bighi (1) and Pollard ( 2 ) . We could not reproduce Righi’s separation of Hg2+2and Hgf2. The separation of Sbf3 and Sb+5, as reported by Pollard, requires 1 hour, and Sbf6 tails. Neither Bighi nor Pollard mentions the selectivity of the separations. Therefore, we have made a more detailed study and developed faster and more selective solvent systems.
using reagent grade chemicals. All solvents were purified b y distillation. Mercury Test Solution. Three grams of freshly prepared mercurous nitrate (mercurous nitrate E. Merck, which contains a n appreciable quantity of mercuric nitrate, was treated with dilute nitric acid and mercury until colorless crystals of mercurous nitrate appeared) were dissolved in 50 ml. of approximately 3M Hn’03. Two grams of mercuric nitrate were boiled with 5 mi. Spotting was done of concd. “0,. with 0.1M solutions. Ammonia gas and ammonium sulfide were used as detectors. Antimony Test Solution. The Sb+8 solution, 0.2M, was prepared as reported earlier (4). The 0.2M SbC13 solution in HC1 was boiled with KClOa, cooled, and filtered. This was used as the Sb+5 solution. Ammonium sulfide and H2S gas were used as detectors. Rhodamine B was used for the detection of Sb+5 only.
EXPERIMENTAL
To develop suitable methods of separation, a number of pure solvents were examined. The results are summarized in Table I. Separation of Hgz+2 and Hgf2. The following solvent systems gave fast separations of Hgz+* and Hg+2: 0.1M €IC1 ( S I ) ; 15% aqueous am-
Apparatus. Development was performed in 20-X 5-cm. glass jars, using the ascending method. T h e diniensions of the paper strips were 15 X 4 cm. Reagents. All results were obt,ained on Whntmwn No. 1 paper
RESULTS
monium acetate-3M Hvo3-3LT1 HC1 (6: 1: 1) v./v.(82);3M Hn'Oa-3M HC1isobutanol (1: 1: 10) 1 ./v. (Sa); and 3 J1 H i S03-3 114 H C'l-i o p r o p a n ol (1 : 1 : 10) v./v. (&). In all these solvent bystems, Hg2+zhas an Rf value of 0.00. SI is the simplest system giving fast irparations (R, Hg+2 = 0.81). When tire coriwntration of IICl is gradually v a r i d from 0.1Ji to approximately 3.00?/1, tlie tJ50 Rf v a h m as expectd rcinain almost constant. In 3-11 HCl. tlie HgZA2spot is mther elongated. In S2, Hg+2 has an l i ' f value of 0 84. Khen the proportions of Hg+2 and Hg,'* in the sample were gradually varied from 4 : l to 4 16, the two R f values remained constant. When the concentration of the sainple applied was gradually altered from 0.2 to 0.01M, no significant change eithw in efficiency of separation or in the Rf values was found. After 5 minutes of development the distance between the spot boundaries was 1 9 cm. Of the common cations studied as impurities, only Ag+. Sn+2, and B i h 3 affected the separation. In all other cases, good separations were obtained. Sn +2 affects the separation by its reducing action on the Hg2+?-Hg+*system. In 8 3 , Cd+Z (Rf= 0.30), Bi+3 = 0.30), and As+3 (0.40) have Rfvalues significantly different from those of Hg2+2 and Hg+2 (R! = 0.61). Sa is even more selective than S3. Cations having Rr values different from those of Hg;' and Hg+2 (Rr = 0.66) are As+3 (043), Sn+' (0.90), Fe+3 (0.30), Al+3 (0.20), Cr+3 (0.30), M n f 2 (0.22), Ca+Z (0.20), Ba+2 (0.20), 3r+2 (0.24), and Mg+Z (0.22). Cation
