been reported for gas liquid partition chromatography. In most works concerning partition chromatography the authors substitute freely the rational partition coefficients following from Nernst’s law (Zk = z1/z2, concentrations expressed in mole fractions) by the ordinary partition coefficient which is employed in the theory of partition chromatography (k = c1/c2, concentrations expressed in mole/volume scale). Even the same symbol, a, is used to denote the two
coefficients. And yet the coefficients Dissert. Univ. Warsaw, NO. 4, PWN are not identical: zk = I c ( s 0 / u 2 0 ) where Warsaw, 1963. ( 3 ) Collander, R., Acta Chem. Scand. 5, soJu2O are the molar volumes of the 774 (1951). two phases and the solutions are (4) Connors, K. A., ANAL. CHEM.37, 261 (1965). assumed to be dilute [cf. Buchowski (D]. ( 5 ) Kabasakalian. P.. Basch., A.., Ibid.. 32, 458 (1960).’ ’ (6) Soczewinski, E., Chem. Anal. (Warsaw) 8, 337 (1963).
LITERATURE CITED
(1) Bate-Smith, E. C., Westall, R. G., Biochim. Biophys. Acta 4, 427 (1950). (2) Buchowski, H., The Effect of. the Properties of Solvents on Partition Coefficients of Nonelectrolytes between
Water and Organic Solvents (in Polish),
EDWARD SOCZEWINSKI Department of Inorganic Chemistry Medical Academy ul. Staszica 6. Lublin, Poland
Analysis for Microgram Quantities of Thorium in Plutonium Neptunium and Uranyl Nitrate Solutions SIR: Process tests for separating the uranium-233 values from irradiated thorium oxide fuel are to be carried out in the Purex process (6). After each test, thorium impurities must be detected and measured in the normal process products; plutonium, uranium, and neptunium nitrates. Because of the low specific activity of natural thorium232, radiometric means of detection do not apply in trace quantities. The colorimetric technique to be used, thoron, required a well-purified thorium fraction, since gross quantities of the above named products would interfere seriously. A large number of thorium separations techniques have appeared in the literature. Two very good reviews have been published (2, 4). Ion exchange techniques predominate in the more recent publications. A cation exchange procedure (11) using strong hydrochloric and nitric acid eluents for selective stripping has been reported. Anion exchange methods are based on formation of the thorium nitrate complex (1, 6) ; an ascorbinate-thorium complex (6) ; the sulfate complex (3); or the nonformation of a thoriumhydrochloric acid complex (7). The latter case is most attractive because only the column effluent must be accumulated, with no long elution period to be observed. Plutonium(II1) is the only other major element of interest that would not be absorbed on the anion exchange resin.
Table
I.
Liquid-liquid extraction is more desirable than ion exchange since less time is used to make the separation. Use of a tertiary amine to extract uranium from a sample followed by a primary amine extraction for thorium was reported by Petrow, Sohn, and Allen (8). Ross and White (9) discussed an extraction with tri-n-octyl phosphine oxide (TOPO) from solutions containing sulfate and phosphate. The same authors published a review (10) of cation separations with TOPO. Because large sample volumes would be required to find the thorium contaminate in gross concentrations of plutonium, uranium, and neptunium, the probable need for a two-cycle purification of thorium was considered. An anion exchange adsorption from a hydrochloric acid matrix was considered for the first cycle gross separation; while thorium would not be retained on the resin, most other elements should be. Elimination of an elution step would reduce the time required to complete this cycle. The final thorium purification would be accomplished by liquid-liquid extraction with TOPO. EXPERIMENTAL
Reagents. The chloride form anion exchange resin, AG 1 X 8, 100 to 200 mesh, was obtained from the BioRad Co. in a n analytical grade. The resin was preconditioned with 9 M hydrochloric acid prior to use.
Thorium Decontamination from Plutonium(lll) and (IW, Neptunium the Uranyl Ion
c./m. in ion exchange Element Pu239(III) Pu239(IV) NP2YV) UZ3302+e
1440
c./m. taken 7.08 X lo7 8 . 6 7 x 104 2 . 4 4 x 107 1.59 X 108
ANALYTICAL CHEMISTRY
effluent 5 . 4 9 X 106 1 . 5 6 x 103 160 1.57 X 106
c./m. in 0.01M TOPO 2 . 2 5 X lo6 96 16 1 . 5 6 X 106
(‘4,
c./m. in HCl strip
and
1.12 x 106
