Be separations. Twenty milliliters of sodium beryllate solution, containing 15 mg. of Be0 Be7 in 10% NaOH, was passed through ca. 4 ml. of Fe(0H)B resin column, pretreated with 10% NaOH. After washing with 10 ml. of 10% NaOH the recovery is high, while the contamination of iron is small. Beryllium hydroxide was recovered from the effluent. The addition of about 0.01 mole of E D T A is effective in masking iron and other ions a t this point. With carrier-free Be’, however, recovery is lower, presumably because of adsorption. The resin column was treated with ca. 4 M HC1 t o elute iron and any residue of beryllium. The counting rate of Be7 in this effluent showed retention of Be on the column to be ca. 0.5%. This method of decontamination is convenient and reproducible for any anion or amphoteric element. The radiochemical purification of Sod-* can be done in this way. The method has also been used for radiochemical purification of C1. An ammoniacal solution of AgCl was passed through the column. The effluent contained no silver. Lure and Fillipova (17) proposed a similar method for the separation of amphoteric ions from Fe and others. I n their method, A1, Be, etc., were eluted with NaOH solution successively after the adsorption of all cations on a cation exchange resin in H R form. This method has not yet been applied extensively because of low quantitative recovery due to coprecipitation in the
+
column. For radiochemical hork it might still be useful for decontamination. ACKNOWLEDGMENT
We are indebted to E. F. X. Lyden for carrying out the solvent extraction experiments on the large core samples, and to him and our colleagues a t Princeton for helpful discussions. Emission spectrography of the sea water samples was performed by Anthony Leoni and Norman Nachtrieb.
LITERATURE CITED
(1) Adam, J. A,, Booth, E., Strickland, J. D. H., Anal. Chim. Acta 6. 462 f 1952). (2) Arnold, J. R., Science 124, 584 (1956). (3) Arnold, J. R., Al-Salih, H. A., Ibid., ’ 121,451 (1955). (4) Bjerrum, J., Schwarzenbach, G., \----,
SillBn, L. G. (compilers), “Stability Constants.” vola. 1. 2. The Chemical Society, Lbndon, 1957, i958. (5) Boyd, G. E., Adamson, A. W., Myers, L. S., Jr., J . Am. Chem. SOC.69, 2836
(1947). (6) Ehmann, W. D., Kohman, T., Geochim. et Cosmochim. Acta 14, 340 (1958). (7) Fairbairn, H. W., Ibid., 4, 143 (1953). (8) Feldman, I., Haville, I. R., J. Am. Chem. SOC.74, 2337 (1952). (9) Fleischer, M., private communication.
These analyses were made by Barnett and Murata of the U. S. Geological Survey. (10) Goel, P. S., Kharkar, D. P., Lal, D., Narsappaya, N., Peters, B., Yatirajam, V., Deep-sea Research 4,202 (1957).
(11) Holm, R. H., Cotton, F. A,, f.Am. Chem. SOC.80, 5658 (1958). (12) Honda, M., Japan Analyst 3, 163 ‘ (1954’, 4 , 384 (1955). (13, Lionda. M.. J . Chem. SOC.J a m n 71, ‘ 118 r l % O \ : 72.361 (1951). (14)KaKh&a, -H:, D i d , , 72, 203 (1951). (15) Kaluhana, H., Sillh, G., Acta Chem. Scand. 10,985 (1956). (16) Kraus, K. A., Nelson, F., Clough, F. B.. Carlston. R. C.. J . Am. Chem. SOC. 77,1391 (1955j. (17) Lur6, Y. Y., Fillipova, N. A., Zavodskaya Lab. 13, 539 (1947). (18) McIsaac, L. D., Voigt, A,, U. S. At. Energy Comm. ISC-271 (1952). (19) Merrill, J. R., Lyden, E. F. X., Honda, M., Arnold, J. R., Geochim. e.! Cosmochim. Acta 18, 108 (1960). (20) Minami, E., Honda, M., Sasaki, Y., Full. Chem. SOC. Japan 31,372 (1958). (21, Nadkarni, M. N., Varde, M. S., Athavale, V. T., Anal. Chim. Acta 16, 421 (1957). (22) Selson, F., Kraus, K. A4.,J . Am. Chem. SOC.77,801 (1955). (23) Peters, B., Proc. Ind. Acad. Sci. A41,67(1955). (24) Pribil, R., Collection &echoslov. Communs. 16,86 (1951). (25) Sandell, E. B., Geochim. et CosmoChem. chim. Acta 2 , 211 (1952). (26) Schubert, J., Lindenbaum, A., Westfall W., J . Phys. Chem. 62, 390 (1955). (27) kchwwzenbach, G., “Die Komplexometrische Titration,” F. Enke, Stuttr gart, 1955. (28) Schveitzer, G., Nehls, J., J . Am. Chem. SOC.75, 4354 (1953). (29) Sill, C. W., Willis, C. P., ANAL. CHEM.31, 598 (1959). (30) Taketatsu, T., J . Chem. SOC.Japan 79,586, 590 (1958).
RECEIVEDfor review July 13, 1959. Accepted July 22, 1960. Research supported by the Office of Ordnance Research, U. S. Army, and by the Sational Science Foundation.
.
Fluorescimetric Determination of Ruthenium HANS VEENING’ and WARREN W. BRANDT Deportment o f Chemistry, Purdue University, I ofoyefte, Ind.
b A fluorescimetric method for the determination of ruthenium uses the tris(5 methyl 1 ,I 0 phenanthro1ine)ruthenium(l1) complex. With this method 1 y per ml. of ruthenium can b e determined with no interference from 25 y per ml. of osmium. The useful range of concentration is 0.3 to 2.0 y per ml. of ruthenium with an The average accuracy of &2%. other platinum metals do not interfere. Iron is a serious interference.
-
M
-
-
are known to fluoresce (10, 11). This characteristic has proved valuable in providing very sensitive methods for their determination. .4n extension of this approach provides a sensitive method for the determination of ruthenium. 1426
ANY METAL CHELATES
ANALYTICAL CHEMISTRY
The chemical and spectrophotometric properties of the various ruthenium polyamine chelates have been extensively investigated (4). Several recent colorimetric methods for determining ruthenium have been reported (1, 2, 6, 7). A sensitive and accurate spectrophotometric method is based on the stable color of the tris(1,lO-phenanthro1ine)-ruthenium(I1) ion, after separation of ruthenium by distillation ( 3 ) . No reported method currently exists which permits a convenient determination of ruthenium in the presence of other platinum metals. A separation of ruthenium, usually by distillation of the volatile tetroxide (9), must always precede the actual determination. A sensitive determination of ruthenium in the presence of twenty-five times as much osmium or any other
platinum metal is described. Most of the tris-aromatic polyamine complexes of ruthenium(I1) show a red-orange fluorescence when irradiated with blue light. The osmium and iron complexes of the same type did not fluoresce under identical conditions. Of the other platinum metal polyamine chelates, only the bis (bipyridine) -platinum (11) ion has been observed to fluoresce (6). APPARATUS AND REAGENTS
The fluorescence measurements were made with the Spectracord Model 4000, which was modified to function as a spectrofluorescimeter (8). A high pres1 Present address, Department of Chemistry, Bucknell University, Lewisburg, Pa.
10;
400
500
0.1% 5-methyl-phenanthrolineJ 20 ml. of 20% sodium chloride] and 5 ml. of 10% hydroxylamine hydrochloride are added t o the solution. The mixture is adjusted to pH 6.0 using 5M sodium hydroxide or hydrochloric acid. The solution is refluxed for 3 hours, and the fluorescence intensity is measured at 578 mfi in a 1.00-em. mirrored cell at a n analyzer monochromator slit width of 0.60 mm. The fluorescence intensity of the unknown samples can be related to the concentration of ruthenium b y a previously prepared calibration i using curve. I
700
600
A c t i v a t i o n Wavelength I m p )
Figure 1 . Uncorrected excitation spectrum of tris(5-methyl- 1,I O-phenanthroline)-ruthenium(l1)ion
Wovelmq7h
EXPERIMENTATION
Excitation and Fluorescence Spectra for Various Ruthenium Complexes. Several polyammine chelates
Imp1
Figure 2. Fluorescence spectrum of tris(5 methyl 1, I 0 phenanthroline ruthenium(l1)ion
-
-
-
-
of ruthenium(I1) were prepared. Six of these were found t o fluoresce and were examined for excitation and fluorescence characteristics. T h e uncorrected results are shown in Table I. T h e 5-methyl-substituted phenanthroline complex displayed t h e strongest fluorescence of all chelates tested. The 4,4’-bipyridine chelate exhibited the weakest intensity. The excitation and fluorescence spectra of the (&me5-methyl- 1,10-phenanthroline phen) chelate of ruthenium(I1) are shown in Figures 1 and 2. From the standpoint of trace detectability and analytical utility, this latter derivative is the more advantageous using this instrumental setup. Experimentation with mercury and mercuryxenon sources and various excitation wave lengths has shown that under some conditions 5-methyl-1 ,lo-phenanthroline offers no advantage over the unsubstituted compound. The difference in intensity distribution of the sources superimposed on the differences in absorption spectra of the various chelates causes the observed variations. EFFECTOF PH. -4 series of 10P and 10-4iM solutions of the tris(5-mephen) chelate was prepared as described,
sure, 6000-watt, water-cooled xenon and the p H of each mas then adjusted to arc was used as the excitation source. values from 1.0 to 13.0. Fluorescence A Bausch & Lomb Optical Co. grating intensities were measured but no effect monochromator was used to disperse due to p H was noted. the excitation energy which was focused EFFECTO F REAGEST CONCEKTRAon the sample. The latter was conTION. The effects of insufficient or extained in a 1.00-em. cell in the normal tungsten source position of the Spectracess reagent w r e studied by keeping the cord, which was used t o analyze and ruthenium concentration constant a t record the fluorescence spectra. 10-5.1f and varying the reagent conSpectral absorption curves were also centration. Each solution was septaken on the Spectracord using 1.00arately refluxed. Above a 2 to 1 ratio em. quartz cells. Absorbance measureof reagent to ruthenium(I1) a sharp rise ments at a single wave length were made in fluorescelice occurred. Such a rise is with the Beckman Model B spectroobtained to a 10 to 1 ratio where further photometer. Measurements of p H were reagent addition shon ed no effect. made with a Beckman Zeromatic p H REPRODUCIDILITI ASD SC~VSITIVITY OF meter. All aqueous solutions were prepared using water which was disMETHOD. d plot of fluorescenee intilled twice from potassium permantensity us. concentration shon ed a linear ganate. relationship between 0.3 and 2.0 y of For all spectral fluorescence measureruthenium per ml., a t a Spectracord slit ments, the Bausch & Lomb monowidth of 0.60 mm. Fluorescence could chromator entrance and exit slit widths be reproduced to within 1% for a period were 10.0 and 5.0 mm., respectively. of 3 days. All polyamine chelating agents were obtained from the G. Frederick Smith Chemical Co. Ruthenium and rhodium EFFECT OF DIVERSE IONS chloride were supplied b y Goldsmith Bros. Smelting & Refining Co. Qualitative examination of the phenOsmium, palladjum, and iridium chloanthroline complexes of the other platirides were obtained from J. T. Baker num metals indicated that no fluorescent Chemical Co., The American Works, and J. Bishop & Co. Platinum ~ ~ 7 0 r k s , respectively. A standard solution of rutheniumIII1) and aqueous solutions of the tris($ Table I. Uncorrected Activation and Fluorescence Maxima of Various Ruthenium(l1) methyl-1 10-phenanthro1ine)-ruthenium Chelates complex were prepared according to Concn. ruthenium complex, lO-‘,M the method outlined by Banks and O’Laughlin ( 3 ) . Osmium solutions Relative Observed were prepared by weighing out osmium -4ctivaAbFluorestion Fluorescent Maxima sorption cent trichloride (dried in a vacuum desiccaXlaxima, Observed, M/* hIaxima, Intensity, tor) and dissolving in 10% hydrochloric Complexing ilgent M p 1P28 1P21 M/* %T acid. Standard iron(I1) solutions were prepared with weighed amounts of 2,2 ‘-Bipyridine 460 582 580 450 53 Fe(K”&(S04)2. 6 H 2 0 and subsequent 450 590 589 450 21 4,4’-Dimethyl-2,2’-bipyridine dissolution in 10% H2SO4. 465 578 577 450 84 1,lO-Phenanthroline 465 577 575 450 100 5-hlethyl-1 ,10-phenanthroline RECOMMENDED PROCEDURE 465 583 583 450 87 5,6-Dirnethyl-l,lO-phenanthroline 3,5,6,8-Tetramethyl-l,10-phenanAn aliquot of the dissolved sample throline 457 577 574 420 37 containing no strong oxidizing agents and free of iron is treated according t o The 5-chloro- and 5-nitrophenanthrolines, and the terpyridine chelates did not fluoresce. The activation wave length was chosen as 450 mp. the method described b y Banks and O’Laughlin (3). Fifteen milliliters of VOL. 32, NO. 11, OCTOBER 1960
1427
I
I
I
1
1
-
a
’z 40Y
f e
‘.I
1 I
I 50
100 O 8 m i u m pg./ml.
Cons. 5-me-phen..
0.15 M
f E 30-
C a c . R u t h a n l u m . 1.0
)lo/ml.
21 B eoeo
A n o l p e r Slll
Figure 3. Effect of osmiurn(lll) on fluorescence intensity of R~(S-me-phen)3+~
A c t Wovelength
Table 11.
Determination of Ruthenium in Presence of Osmium 10 y/ml. Os(II1) added
Ru, pg./Ml. Added Found 0.40 0.60 1.30 1.80 2.50
0.39 0.61 1.30 1.88 2.47
Error (Rel. Per Cent)
+- 21 ..56 + 04 . 4 -
1.2
20 pg./ml. Os(II1) added 0.40 0.40 0 0.60 0.57 5.0 1.30 1.31 0.8 1.80 1.77 - 1.7 2.50 2.87 f14.8
-
+
Table 111.
2.0 2.0
Added As
Rh(II1) Ir(1V) Pd(I1) Pt(1V) Co(I1) Ni(I1) Cu(I1) Ce(IV) Mn(I1) Mn0,AgU) CrgO,-n Halides 1428
sity from 1.0 y per ml. of ruthenium (Figure 3). I n the presence of 19 7 per ml. of osmium no effect was noted on the calibration curve. Further confirmation was obtained from two series of synthetic mixtures containing ruthenium and osmium. The first series contained 10 y per ml. and the second 20 y per ml. of osmium (111). These mixtures were treated as previously described. The calibration curve prepared with no osmium present wm used to determine the ruthenium content. Each result (Table 11) is the average value of two determinations. The average relative error is *1.9% in the first series and 1 1 . 9 % in the second after discarding the one spurious result. Iron. T h e interference of iron was studied b y preparing a series of solutions containing 1.0 y per ml. of ruthenium and varied amounts of iron. The results (Figure 4) clearly indicate the serious interference of iron which is caused by the initial absorption of energy by the iron complex of &methylphenanthroline. Iron cannot be present in a n amount comparable to that of ruthenium. Other Ions. Measured amounts of various platinum metals and other
ANALYTICAL CHEMISTRY
Concn., 7 m .
30 30 30 30 30 30 30 15 15 15 15 15 50
3.0 3.0
4.0 4.0
5° . 0 5.0
6.0 6.0
7.0 7.0
8.0 8.0
9.0 9.0
10.0 1 10.0
Figure 4. Effect of iron(ll1) on fluorescence intensity of R~(S-me-phen)3+~
Effect of Various Diverse Ions on Fluorescence of 1 y/MI. of Ru(5-mephen)~ +2
Ion
-
450 my
-
Concn. 5-me-phen, 0.1 5M Concn. Ru, 1 .O y/ml. Analyzer dit, 0.87 mm. Activation wave length, 450 m p
interferences with the method would be found. T o confirm this, several metals were checked for interference by other means. O d m . A series of 10-6M Ru(5me-phen)s+* solutions was prepared. Prior to refluxing, various measured amounts of osmium(II1) were added as OsC13. As much as 28 y per ml. of osmium(II1) can be present without interfering with the fluorescence inten-
=
h
1.0 1.0
-
0.87mml
li
10 1
I 150
9
Per Cent Error 0 0
Formed precipitate 0
0 0 0 100 26
Formed precipitate Formed precipitate Formed precipitate 0
ions were added individually t o a solution containing 1 y per ml. of ruthenium(II1) prior to refluxing. The results are illustrated in Table 111. The serious interferences are iron(II), palladium(II), cerium(IV), manganese (II), permanganate, silver(I), and dichromate. The interference due to precipitate formation of palladium with phenanthroline may be removed by centrifugation. The method has a significant advantage since most of the platinum metals do not interfere. EVALUATION
OF
METHOD
The most important advantage of this method is the elimination of a separation of ruthenium and osmium. Satisfactory accuracy of k 1.9% (relative) can be obtained. Using other instrumental arrangements, the less expensive 1,lO-phenanthroline gives equally satisfactory results. The determination can be conveniently performed on a simple filter fluorescimeter. It is conceivable that the method can be made more sensitive by extraction of the perchlorate salt of the chelate into benzyl alcohol which enhances the fluorescence intensity. LITERATURE CITED
(1) Ayres, G. H., Young, F., ANAL. CHEM.22,1277 (1950). (2) Zbid., p. 1281. (3) Banks, C. V., O’Laughlin, J. W., Ibid., 29, 1412 (1957). (4) Brandt, W. W., Dwyer, F. P., Gyarfas, E. C., Chem. Revs. 54, 959-1017 (1954). (5) Marshall, E. D., Rickard, R. R., ANAL.CHEM.22,795 (1950). (6) Pringsheim, P., “Fluorescence and Phosphorescence,” p. 504, Interscience, S e w York, 1949. (7) Stoner, G. A., ANAL.CHEM.27, 1186 (1955). (8) Veening, H., Brandt, W. W., Amy,
J. W., to be published.
19) Westland. H. D., Beamish, F. E., AKAL.C H E26,739 ~ (1954). ’ (10) White, C. E., Zbid., 28, 621 (1956). (11) Zbid., 30, 729 (1958). ,
I
RECEIVED for review March 2, 1960. Accepted August 2, 1960. Anachem Conference, Detroit, Mich., October 26, 1959. Work supported by the National Science Foundation.
