Separation of traces and larger amounts of bismuth from gram amounts of thallium, mercury, gold and platinum by cation-exchange chromatography on a macroporous resin

Traces and larger amounts of bismuth (up to 50 mg) can be separated from gram amounts of thallium, mercury, gold and platinum (up to 5 g) by sorption from a mixture of 0.1M hydrochloric acid and 0.4M nitric acid on a column containing just 3 g (8.1 ml) of AGMP-50, a macroporous cation-exchange resin. This resin retains bismuth much more strongly than does the usual microporous resin (styrene-DVB with 8% cross-linkage). Other elements are eluted with the same acid mixture as that used for sorption, and bismuth is finally eluted with 1.0M hydrochloric acid. Separations of bismuth are sharp and recoveries quantitative. Only microgram amounts of the other elements remain in the bismuth fraction. Amounts of bismuth as little as 5 mug have been separated from 5 g of thallium, and determined (r.s.d. = 2%) by flame atomic-absorption. Only 100-mug amounts of bismuth have been separated from gram amounts of mercury, gold, and platinum, but there is no reason to believe that smaller or larger amounts of bismuth cannot be separated from these elements and recovered with the same accuracy as that for the separation from thallium. The lower limit of the method is determination of 0.4 mug of bismuth in 10 ml of solution (0.004 absorbance). An elution curve, the relevant distribution coefficients and the results of analysis of synthetic mixtures and two practical samples [thallium metal and mercury(II) nitrate] are presented.     

Quantitative separation of traces of lead,cadmium and many other elements from gram amounts of thallium by cation-exchange chromatography

Traces of lead and minor amounts up to 20 mg, can be separated from gram amounts of thallium by cation-exchange chromatography on a column containing only 2 g of AG50W-X4 resin. Thallium passes through the column in 0.1 M HCl in 40% acetone. The retained lead can be eluted with 3 M HCl or HNO₃. Other elements, including Cd, Zn, In, Ga, Cu(II), Fe(III). Mn(II), Co(II). Ni(II), U(VI) and Al, are retained quantitatively with lead. Only Hg(II), Au(III), the platinum metals, bismuth and elements forming oxyanions accompanying thallium. Results for the determination of trace elements in 99.999% pure thallium are presented.     

Separation of traces of manganese,cobalt, nickel and copper from gram amounts of tellurium by cation-exchange chromatography in hydrochloric acid/acetone media

Traces of Mn(II), Co(II), and Ni(II) and minor amounts (up to 20 mg of these elements are separated from gram amounts of tellurium by cation-exchange chromatography on small columns (3 g) of macroporous AG MP-50 resin or larger colunns (5 g) of microporous AG 50W-X8 resin. The trace elements are retained from 0.5 M HCl containing 70% acetone while tellurium passes through and is eluted completely with this solution. The trace elements are then eluted with 3.0 M HCl and can be determined by atomic absorption spectrometry. Copper (II) can also be separated but requires a 10-g column of AG MP-50 resin. Separations are sharp and quantitative and only microgram amounts of tellurium remain in the trace element fraction when a 3-g sample of tellurium dioxide is taken; 10-μg amounts of the trace elements were separated from such samples and determined with standard deviations of <1%. Relevant elution curves and results for the analysis of synthetic mixtures are presented.     

Separation of lithium from sodium,beryllium and other elements by cation-exchange chromatography in nitric acid-methanol

Lithium can be separated from sodium, beryllium and many other elements by eluting lithium with 1 M nitric acid in 80% methanol from a column of AG50W-X8 sulphonated polystyrene cation-exchange resin. The separation factor is not quite as large as that in 1 M hydrochloric acid in 80% methanol, but many elements, such as Zn, Cd, In, Pb(II), Bi(III) and Fe(III), which form chloride complexes in 1 M HCl-80% methanol are retained quantitatively together with Na, Be, Mg, Ca, Mn(II), Al, Ti(IV), U(VI), and many other elements, when 1 M HNO3-80% methanol is used for elution of lithium. A method for the accurate determination of traces of lithium in rock samples is described, and some results obtained are presented together with relevant distribution coefficients, elution curves and results for the analysis of synthetic mixtures.     

The separation of silver from mixtures by cation-exchange chromatography

Summary The cation-exchange behaviour of milligram amounts of silver on Dowex 50 W-X 8 has been studied, with nitric acid, sulphuric acid, ammonium acetate, ammonium nitrate, sodium nitrate, citric acid, tartaric acid, and acetic acid as eluents. A volume of 200–300 ml of 3M nitric acid, sulphuric acid, ammonium acetate, ammonium nitrate, or sodium nitrate was adequate for quantitative removal of 26 mg of silver from a 1.4×19 cm column of resin. Methods are described for the separation of silver from Ce, Zr, Th, Bi, and Fe by conversion of these elements into anionic complexes; from Cu, U, Al, and Zn by selective elution with nitric acid; from Ba, Sr, Sb, and As by elution with specific eluents.

---

Zusammenfassung Das Verhalten von Milligrammengen Silber am Kationenaustauscher Dowex 50 W-X 8 bei Verwendung von Salpetersäure, Schwefelsäure, Ammoniumacetat, Ammoniumnitrat, Natriumnitrat, Zitronensäure, Weinsäure und Essigsäure als Eluenten wurde untersucht. 200 bis 300 ml 3-m Salpetersäure, Schwefelsäure, Ammoniumacetat, Ammoniumnitrat oder Natriumnitrat waren hinreichend für die quantitative Elution von 26 mg Silber aus einer Harzsäule von 1,4×19 cm. Methoden zur Trennung des Silbers von Ce, Zr, Th, Bi und Fe durch Überführung dieser Elemente in Komplexanionen wurden beschrieben. Die Trennung von Cu, U, Al und Zn gelingt durch selektive Elution mit Salpetersäure, von Ba, Sr, Sb und As durch Elution mit spezifischen Eluenten.

---

Résumé On a étudié le comportement de quantités d'argent de l'ordre du milligramme du point de vue échange cationique sur Dowex 50 W-X 8, avec différents éluants: acide nitrique, acide sulfurique, acétate d'ammonium, nitrate d'ammonium, nitrate de sodium, acide citrique, acide tartrique et acide acétique. Un volume de 200–300 ml d'acide nitrique 3M, d'acide sulfurique, d'acétate d'ammonium, de nitrate d'ammonium ou de nitrate de sodium est nécessaire pour l'élimination quantitative de 26 mg d'argent d'une colonne en résine de 1,4×19 cm. On décrit des méthodes de séparation de l'argent d'avec Ce, Zr, Th, Bi et Fe par conversion de ces éléments en complexes anioniques; d'avec Cu, U, Al et Zn par élution sélective par l'acide nitrique; d'avec Ba, Sr, Sb et As par élution avec des éluants spécifiques.

---

---

We wish to thank Dr.R. A. Chalmers for helpful discussion and suggestions.     

Separation of nickel from other elements by cation-exchange chromatography in dimethylglyoxime/hydrochloric acid/acetone media

Nickel can be separated from Zn, Co, Cu(II), Mn(II), Fe(III), U(VI) and other elements which readily form chloro complex ions, by eluting them with 0.5 M HCl/93% acetone from AG50W-X4 resin. Nickel is then eluted selectivity with 0.5 M HCl/95% acetone containing 0.1 M dimethylglyoxime, while the alkali and alkaline-earth elements, Al, Ti(IV), Sc, Y, La, lanthanides, Zr, Hf and Th are still retained. Separations are sharp and quantitative.     

Separation of trace amounts of indium, gallium and aluminium from each other by cation-exchange chromatography on AG50-X4 resin

Traces and minor amounts of indium, gallium and aluminium can be separated from gram amounts of thallium and from each other by cation-exchange chromatography on a column containing as little as 2 g of AG50W-X4, a cation-exchange resin with low cross-linking. An elution sequence of 0.1 M HBr in 40% acetone [for Tl(III)], 0.2M HBr in 80% acetone for In, 0.3M HCl in 90% acetone for Ga and 3M aqueous HCl for Al is used. The separations are very sharp and even 10-mug amounts of In, Ga and Al in synthetic mixtures are recovered quantitatively, with a standard deviation of 0.3 mug. The separation factors between neighbouring ions are extremely large (> 5000).     

Quantitative separation of lanthanides and scandium from barium,strontium and other elements by cation-exchange chromatography in nitric acid

The lanthanides plus yttrium and scandium are separated from Ba, Sr, Ca, Mg, Pb(II), Bi(III), Zn, Mn(II) and U(VI) by eluting these elements with 2.0 M nitric acid from a column of AG50W-X8 cation exchange resin (200-400 mesh). The lanthanides are retained and can then be eluted with 4 M nitric or hydrochloric acid. Separations are quantitative and applicable to microgram and millimolar amounts of the lanthanides and the other elements. Elements such as Cu(II), Co(II), Ni(II), Cd. Hg(II), T1(I). Ag, Be, Ti(IV) and the alkali metals should accompany barium quantitatively according to their known distribution coefficients. Relevant elution curves and results of analysis of synthetic mixtures are presented.     

Separation of gram quantities of uranium from fission products by extraction chromatography

The separation of gram quantities of uranium from fission products has been investigated by extraction chromatography. The separation which is based on the difference in distribution coefficients between uranium and the fission products on a tributyl phosphate (TBP) resin in nitric acid medium, was carried out by means of high acidity feed and stepwise elution on a TBP chromatography column. The results show that this technique is capable to separate 5 g of uranium from a large quantity of fission products. The recovery of uranium is more than 99%. The decontamination factors of g- and b-activities were 2.1^.10³ and 2.3^.10³, respectively.     

Separation of lead-203 from cyclotron-bombarded thallium targets by ion-exchange chromatography

A simple method is presented for the separation of lead-203 from copper-backed thallium cyclotron targets. The procedure involves cation-exchange chromatography in hydrochloric acid and hydrochloric acid-acetone mixtures. Further purification involves anion-exchange chromatography in nitric acid-hydrobromic acid mixtures. A cation-exchange column containing 3.0 g of resin can handle as much as 15 g of thallium and 160 mg of copper. An anion-exchange column containing 3.0 g of resin can separate lead from up to 200 mg of thallium and 10 mg of copper. Separations are extremely sharp and less than 0.1 mug of thallium and less than 0.1 mug of copper remain in the lead-203 fraction.     

Accurate determination of trace amounts of thorium in silicate rocks by cation-exchange chromatography and spectrophotometry

Thorium in four of the South African NIMROC standards and in four secondary standards is determined accurately by means of spectrophotometry with arsenazo-III after a selective cation-exchange separation on an AG50W-X4 resin column. All other elements are eluted with 6 M hydrobromic acid before the final elution of thorium with 5 M nitric acid. Small amounts of zirconium which may be present in the thorium eluate, are effectively complexed with oxalic acid which also eliminates the spectrophotometric interferences caused by organic material leached from the resin column. The accuracy and precision of the method are demonstrated by the analysis of synthetic mixtures containing various amounts of thorium. Amounts of 10 and 100 μg of thorium can finally be determined with coefficients of variation of 1% and 0.2%, respectively.     

Improved separation of cadmium-109 from silver cyclotron targets by anion-exchange chromatography in nitric acid—hydrobromic acid mixtures

A method is presented for improved separation of ¹⁰⁹Cd from silver cyclotron targets. After dissolution of the target material in nitric acid and removal of silver by precipitation with copper metal, at pH 5, the cadmium is separated from zinc, copper and other elements by anion exchange chromatography. The solution in 0.5 M nitric acid plus 0.1 M hydrobromic acid is percolated through a column containing 4 ml of AG1-X8 anion-exchange resin (100–200 mesh), equilibrated with the same acid mixture. Zinc, copper(II) and other elements are eluted with 50 ml of this mixture. Cadmium is retained and finally eluted with 50 ml of 3 M nitric acid. The cadmium is retained much more strongly from the hydrobromic acid mixture than from the 0.02 M hydrochloric acid used for such separations previously; the presence of the strongly absorbed nitrate anion in fairly high concentration completely eliminates the tailing of zinc observed in 0.02 M hydrochloric acid. A typical elution curve and results of quantitative separations are presented.     

Separation of alkaline earth elements by cation-exchange chromatography in ammonium malonate media

Be(II), Mg(II), Ca(II), Sr(II) and Ba(II) can be separated by elution from a cation-exchange column in the ammonium form with increasing concentrations of ammonium malonate. A typical elution sequence for a 60-ml column (volume in H⁺-form) of AG₅₀-X8 resin is: 200 ml of 0.20 N ammonium malonate plus 0.10 N malonic acid for Be(II); 300 ml of 0.50 N, 450 ml of 0.70 N, 350 ml of 1.10 N ammonium malonate for Mg(II), Ca(II) and Sr(II), respectively, and 200 ml of 3.0 N nitric acid for Ba(II). Separations are sharp and quantitative for element pairs in weight ratios from 1:1000 to 1000:1. Distribution coefficients, elution curves and quantitative separations are presented.     

Separation of protein mixtures using pH-gradient cation-exchange chromatography

Historically, separation of a protein mixture after adsorption to a cation-exchange column is effected by alteration in ionic strength. An alternative separation method using pH induced gradient in the range of 4–7.5 was studied. A cation-exchange column with large particle beads containing excessive carboxyls was employed. A pH gradient across the column was generated by a step change at the column entrance using a non-retained buffer system. Consistency and accuracy of pH values in timed intervals were demonstrated in three different batches. In development of the application, we found a correlation coefficient of >0.9 between the elution pH values of six acidic proteins and their isoelectric points. One case study showed the resolution between a monoclonal antibody and non-retained protein species from a protein A column. Another case study showed the feasibility of separating polyethylene glycol conjugated protein from native protein.     

Solvent extraction of lead,silver, antimony and thallium with zinc dibenzyldithiocarbamate and its application to the separation of bismuth from large amounts of lead

Solvent extraction of lead, silver, antimony and thallium from various acid solutions was investigated with zinc-DBDTC as chelating reagent. These metals were quantitatively extracted over a wide range of acidity with 0.03% zinc-DBDTC solution in carbon tetrachloride. A separation procedure for bismuth from large amounts of lead was developed; bismuth was extracted from 1 M nitric acid with zinc-DBDTC and was separated from lead by subsequently washing the organic phase once with 3.5 M hydrochloric acid or twice with 3 M hydrochloric acid. Satisfactory results were obtained in separating microgram amounts of bismuth from 1 g of lead.     

Determination of trace amounts of zirconium in silicates by cation-exchange chromatography and spectrophotometry with xylenol orange

An ion-exchange scheme and colorimetric determination with Xylenol Orange are used for estimating traces of zirconium in silicate rocks.     

Reversed-phase foam chromatography: Separation of trace amounts of cobalt from nickel in the tri-n-octvlamine-hydrochloric acid system

The separation of cobalt and nickel in hydrochloric acid media by reversed-phase chromatography on open-cell polyether-type polyurethane foam columns loaded with tri-n-octylamine hydrochloride has been studied. The results showed that good results are obtained with 11.4 and 17.7% loadings of the amine. The separation was studied in the Ni:Co range from 1 to 10⁸.     

Separation of traces of silver in nitric acid solutions using mercury as collector

Summary Microgram quantities of silver are quantitatively deposited into mercury globules from nitric acid solutions (ca. 1N acidity), leaving large amounts of base metals (e. g., copper, lead, and bismuth) in solution. This separation method has been applied to the atomic absorption spectrometric determination of a few ppm of silver in copper or lead.

---

Zusammenfassung Mikrogrammengen Silber werden aus salpetersaurer Lösung (ca. 1-n) quantitativ auf Quecksilbertröpfchen niedergeschlagen, wobei große Mengen unedle Metalle (z. B. Cu, Pb und Bi) in Lösung bleiben. Diese Trennmethode wurde bei der Bestimmung weniger ppm Silber in Kupfer oder Blei durch Atomarabsorption angewendet.