Separation Of Microgram Quantities Research Articles

Quantitative analysis of primary aluminum by densitometric thin-layer chromatography

A simple TLC method with scanning densitometry has been established for quantitative analysis of primary aluminum. The presence of microgram amounts of two major elements as impurities in the concentrated aluminum matrix was successfully detected. Chromatography on microcrystalline cellulose pre-developed with 10% sodium molybdate, dilute hydrochloric acid (3–5%), and sodium molybdate in specific ratios was used for the detection of silicon in smelter-grade aluminum. Silica gel H, silica gel G, and their combinations with aluminum oxide G were used for chromatographic study of iron and aluminum. Aqueous mixtures of formic acid and salt solutions of sodium chloride, sodium formate, potassium chloride, and potassium bromide were used as mobile phases for realizing ideal separation of microgram amounts of iron from milligram quantities of aluminum. Quantitative densitometric analysis of aluminum, iron, and silicon was achieved by measuring absorbance at 530–520, 628–560, and 410–395 nm, respectively, in refl...

A novel method for trace uranium determination in plutonium by thermal ionisation mass spectrometry

An isotope dilution-thermal ionisation mass spectrometric (ID-TIMS) methodology using enriched 235U (>90 at.%) as a spike is described for the determination of trace uranium (U) in plutonium (Pu). The method is based on the monitoring of UO + instead of U + in order to overcome the isobaric interference of 238Pu at 238U. The present approach obviates the need for the chemical separation of microgram quantities of U from relatively large amounts of Pu. This method is useful for determining decontamination factors during U–Pu chemical separation, and also for determining trace U in a proposed Pu chemical assay reference material. In practice, the U isotopic concentration in the Pu sample must be known for highly accurate results.

Inducement of a New Micellar Mobile Phase for Thin-Layer Separation and Quantitative Estimation of Aluminum(III) in Bauxite with Preliminary Separation from Iron(III) and Titanium(IV)

ABSTRACTSilica gel has been used as a stationary phase in combination with surfactant-mediated acidic eluents for thin-layer chromatography (TLC) of 14 metal cations. Several combinations of mobile-phase systems comprising different surfactants (anionic, cationic, and nonionic) and carboxylic or mineral acids have been tested for rapid and reliable separation of metal cations. The results obtained on plain silica gel were compared with those obtained on plain alumina, cellulose, and keiselguhr, as well as on mixed adsorbents. The TLC system constituting silica gel as a stationary phase and 0.001 M aqueous sodium Ms(2-ethyl hexyl) sulfosuccinate plus 1.0 M aqueous formic acid (1:1, v/v) as a mobile phase was identified as the most favorable system for the separation of coexisting Al3+, Fe3+, anti Ti4+ in the presence of common organic and inorganic impurities. The proposed method is rapid and is suitable for identification and separation of AI3+, Fe3+, and Ti4+ from sea, river, tap water, and bauxite ores. The separation of microgram quantities of Al3+ from milligram quantities of Fc3+ or vice versa and parameters such as limits of detection, reproducibility, and repeatability were studied. Quantitative determination of Al3+ in bauxite ores was done by TLC spectrophotometer.

Adsorption Studies of Metal Cations on a Silica Static Flat Bed Using Anionic Micellar Mobile-Phase Systems Containing Carboxylic Acids: Separation of Co-Existing Iron(III), Copper(II) and Nickel(II) Cations

Silica gel was used as a stationary phase in combination with an acidic surfactant containing eluents for the thin-layer chromatography (TLC) of 10 metal cations. Several combinations of mobile-phase systems consisting of sodium dodecyl sulphate (SDS) and carboxylic acids, alcohols and inorganic electrolytes have been tested for the rapid and reliable separation of metal cations. The TLC system employing silica gel as the stationary phase and 5% aqueous SDS plus 1% aqueous acetic acid (1:1, v/v) as the mobile phase was identified as being the most favourable system for the separation of co-existing nickel, copper and iron cations in the presence of common organic and inorganic impurities. The proposed method was rapid and applicable to the identification and separation of Fe3+, Cu2+ and Ni2+ cations from sea, river and tap water, and from real and synthetically prepared ores and alloys. The separation of microgram quantities of Cu2+ cations from milligram quantities of Ni2+ cations and the semi-quantitati...

Analysis of UVA-Related Alterations upon Aging of Eye Lens Proteins by Mini Two-Dimensional Polyacrylamide Gel Electrophoresis

This study is a first approach to identify UVA-related alterations in situ of bovine eye lens proteins from the water-soluble and urea-soluble fractions upon aging. The fractions were obtained from irradiated long-term organ culture lenses and analyzed by mini two-dimensional gel electrophoresis. This micropreparative method followed by computer analysis allows high resolution and separation of microgram quantities of proteins and to detect spots which arose as a consequence of irradiation. To facilitate the analysis we first separated the water-soluble fraction into the major crystallin classes by gel filtration. Moreover, we immunoblotted the gel of the urea-soluble fraction with a specific antibody against the intermediate filament protein vimentin. Upon irradiation of young and adult lenses, αA-crystallin and vimentin showed obvious modifications. During aging the susceptibility to irradiation increased when vimentin started to degrade, whereas deamidation of αA-crystallin seems to occur.

Separation of microgram quantities of As(V), As(III) and organoarsenic species in aqueous solutions and determination by energy dispersive X-ray fluorescence spectrometry

A procedure was developed for the separation and independent determination of microgram quantities of As(III), As(V), dimethylarsinic acid (DMAA) and phenylarsonic acid (PAS) in aqueous solution. The arsenic species were collected one by one from the same sample solution, by adsorbing them onto metal-loaded activated charcoal (MC*). PAS was separated by adsorption onto VC* and As(V) remaining in the filtrate was collected onto LaC*. The LaC* was filtered out and As(III) in the filtrate was separated by 1-pyrrolidinecarbodithioic acid, ammonium salt (APDC) coprecipitation, where Fe3+ acted as carrier and the precipitate was bound onto activated charcoal. Finally DMAA in the filtrate was collected onto ZrC*. Arsenic concentration in the metal-loaded activated charcoal was measured directly by energy dispersive X-ray fluorescence spectrometry (EDXRF). The detection limits for all four arsenic species were better than 0.02 mg L–1. The amount of unadsorbed arsenic was determinated by vapour generation atomic absorption spectrometry (VGAAS) or graphite furnace atomic absorption spectrometry (GFAAS).

Separation of microgram quantities of Cr(III) and Cr(VI) in aqueous solutions and determination by energy dispersive X-ray fluorescence spectrometry

A procedure was developed for the separation and independent determination of microgram quantities of Cr(VI) and Cr(III) in aqueous solution. Cr(VI) was adsorbed onto zirconium-loaded activated charcoal (ZrC ∗), and Cr(III) was collected by Fe(OH) 3 precipitation and the precipitate bound to activated charcoal. Chromium in the activated charcoal was measured by energy dispersive X-ray fluorescence spectrometry. The detection limits for both chromium species were better than 0.05 mg/l. The procedure was tested with the Ground Water and Waste Water Pollution Control Check Standard WP-15 spiked with Cr(VI) and several samples from the plating industry.

Extraction and separation of uranium and lead with liquid anion-exchangers

A method is proposed for the extraction and separation of microgram amounts of uranium(VI) and lead(II) from sodium salicylate solution with high molecular-weight amines such as Aliquat 336, TOA, TIOA, Amberlite LA-1 or Amberlite LA-2 dissolved in xylene. From a critical study of pH, salicylate concentration, amine concentration, diluent and period of equilibration, the optimum conditions were identified. The method permits separation of uranium and lead from binary mixtures with metal ions commonly associated with them, the determination of uranium, and of lead in air samples.

Separation of microgram quantities of cadmium(II) from milligram quantities of zinc(II) and of copper(II) from nickel(II) and cobalt(II) with aqueous sodium formate-halogen anion systems

The chromatographic behavior of certain cations on silica gel layers with aqueous sodium formate-halogen anion systems has been studied. Several important separations in different solvent systems have been achieved. The effect of various important factors, such as sample concentration, eluent concentration, pH of salt solution, pH of mobile phase, and the presence of anions in the sample solution, on the separations of Cd 2+ from Zn 2+ and of Cu 2+ from Ni 2+, Co 2+, and Cd 2+ was examined.

TLC Separation of Microgram Quantities of Iron(II) from Milligram Quantities of Iron(III)

Abstract A TLC method has been developed for the separation of microgram quantities of Fe(II) from milligram quantities of Fe(III) by using formic acid-butanol-ethyl methyl ketone as mobile phase. The separation is not effected by the presence of chloride, bromide, sulfate, sulfite, acetate and phosphate ions. Good separation was achieved when the pH of the sample solution was kept near to 1.0.

Solvent extraction separation of T1/I/ from T1/III/ with sulphoxides

A method for the separation of microgram quantities of T1/I/ and T1/III/ from hydrochloric acid solutions has been developed. T1/III/ was extracted as HTlCl4 into benzene by di-n-pentyl sulphoxide /DPSO/ and di-n-octyl sulphoxide /DOSO/. Conditions for the effective extraction of T1/III/, free from T1/I/, have been worked out.

Liquid anion-exchange extraction and separation of yttrium, neodymium and samarium

Yttrium, neodymium and samarium are extracted from sodium succinate solution with tri-n-octylamine in benzene and determined spectrophotometrically. Procedures for the separation of microgram amounts of Y, Nd and Sm from La, Sc, Dy, Hf, Zr, Ce(IV), Th and U(VI) are described.

Extraction of palladium isotopes in irradiated actinides

A method is described for the carrier-free separation of microgram quantities of fission product palladium from dissolver solutions of irradiated actinides. The separation is effected by extracting the dimethylglyoxime (DMG) complex with chloroform. This extraction is followed by the destruction of the DMG complex with nitric and perchloric acids. Analysis of the sample is then preformed by surface ionization mass spectrometry using a modified silica gel technique. Radioactive tracers were used to follow the palladium and the most likely mass interferences, ruthenium, silver, and cadmium, through the procedure. A palladium yield of 50-60% and decontamination factors for ruthenium of >4 x 10/sup 4/, for cadmium of >10/sup 4/ and for silver of >10/sup 5/ were obtained at the microgram level. Analysis of several aliquots of a dissolver solution of irradiated /sup 239/Pu demonstrated that the achieved purification was sufficient for mass spectrometric analysis of palladium at the microgram level. 1 figure, 1 table.

Synthetic Inorganic Ion-Exchangers. XX. Thin Layer Chromatography of Metal Ions on Lanthanum Antimonate. Quantitative Separation of Hg(II) from Several Metal Ions

Abstract The analytical potential of Lanthanum antimonate as an ion exchanger has been explored by thin layer chromatographic (TLC) technique. Binder-free thin layers of Lanthanum antimonate have been explored for several important binary and ternary separations. A TLC method has been developed for quantitative separation of microgram quantities of Hg(II) from several metal ions by using 1,4 dioxane as solvent.

Rapid separation of microgram amounts of metal ions on stannic antimonate ion-exchange paper

Microgram amounts of metal ions have been separated using stannic antimonate paper. Most of the separations can be accomplished within 15 minutes.

Froth flotation separation of small amounts of thorium by means of Arsenazo III and Zephiramine

A method is described for the separation of microgram amounts of thorium by means of froth flotation. The thorium-Arsenazo III complex is concentrated from 0.3 M hydrochloric acid solution into the scum in the presence of a quaternary ammonium compound, Zephiramine, which acts as a cationic surfactant. Effects of Arsenazo III concentration, Zephiramine concentration, acidity, and foreign ions have been studied. Thorium is determined spectrophotometrically with Arsenazo III. Behaviour of selected fission-product nuclides during systematic flotation separation has also been studied.

Separation of Microgram Quantities of Aluminum from Silver Matrices Prior to Its Determination by Atomic Absorption Spectrophotometry

Abstract A procedure for the separation of aluminum at levels of 10 to 100 μg/g from silver matrices has been developed. The method is based upon the selective isolation of the silver bulk by reduction with formic acid and the amalgamation mercury-silver. An atomic absorption spectrophotometric technique was applied to the determination of aluminum impurities. Interferences were found to be negligible, and experimental tests show complete recovery of aluminum. An analytical precision of about 3 to 4% was obtained.

Desorption of small quantities of chloraurate ions retained on anion-exchangers, in the separation of gold from base metals

Favourable conditions have been found for the elution of chloraurate ions, separated from base metals by sorption on Dowex 1. The elution is done at 50° with a hydrochloric acid solution of thiourea. A reversible column is proposed for the purpose, the use of which decreases the eluate volume. The conditions established have been applied in the separation of microgram amounts of gold from nickel, copper and iron as well as for determining gold in anodic copper.

Synthesis of chelate resins from chloromethylated styrene copolymers

1. A study was made of the possibility of synthesizing chelate sorbents by the chloromethylation of styrene-divinylbenzene copolymers, followed by their amination with aminoazo compounds that contain various functional groupings that can be used for analytical purposes. The degree of chlorine replacement during amination is 0.4–2.5%. 2. The capacity of the sorbents, obtained from copolymers of different structure, was determined for copper and lanthanum. The resins, obtained from copolymers with a macroporous structure, have the maximum exchange capacity. 3. The resins can be used for the concentration and separation of microgram amounts of the elements.

Separation of microgram quantities of dicarboxylic acids by anion-exchange chromatography

Complex mixtures of dicarboxylic acids are separated by anion-exchange chromatography in sodium phosphate and determined automatically by chromic acid oxidation with silver sulphate as catalyst. The influence of column loading, temperature and eluent composition is described. The size of the anions, the acid strength of the parent acid and non-polar contributions have important effects on the retention volume.