Spectrophotofluorimetric determination of terbium, europium and samarium with pivaloyltrifluoroacetone and tri-n-octylphosphine oxide in micellar solution of nona-oxyethylene dodecyl ether

The fluorescence intensities of terbium, europium and samarium complexes with several beta-diketone derivatives in the absence and presence of tri-n-octylphosphine oxide (TOPO) in micellar solution of nona-oxyethylene dodecyl ether (BL-9EX) were examined. The spectrophotofluorimetric determination of terbium (1.5-1500 ng/ml) has been investigated with pivaloyltrifluoroacetone (PTA) and TOPO in 0.5% micellar solution (pH 3.8-4.5) of BL-9EX. The excitation and emission wavelengths were 309 and 542 nm, respectively. Europium and samarium could be determined by a similar method.     

Spectrophotometric study and analytical application of rare-earth Tiron complexes-II Determination of europium

The absorption spectra of europium-Tiron complexes in aqueous solution have been measured from 340 to 600 nm. The absorbance at 390 and 420 nm follows Beer's law up to 0.8 mg ml (pH 6.2-6.6). Other rare earths except for cerium(III) did not interfere. The interference of cerium could be removed by addition of ascorbic acid. The combining ratio of Tiron to europium has been found to be 1:1.     

Partition of Europium(III) with β-diketones and neutral additives between micellar and bulk phases in aqueous nonionic surfactant solutions

The dstribution ratio of europium(III) with a β-diketone and a neutral adduct between micellar and bulk phases in aqueous nonionic surfactant solution was measured by a spectrofluorimetric method as a function of hydrogen ion concentration. The synergic effect of trioctylphosphine oxide for the various β-diketone chelates is much greater than that of tributyl phosphate.     

Spectrophotometric study and analytical application of rare earth tiron complexes-I Determination of neodymium, holmium and erbium

The absorption spectra of neodymium, holmium and erbium Tiron complexes in aqueous solution have been measured from 340 to 650 nm. The absorbance at the wavelength of maximum absorption band of an aqueous medium containing neodymium (pH 4.5), neodymium (pH 12.0), holmium (pH 5.0) and erbium (pH 5.0) Tiron complexes was about 4 (at 578 nm), 9 (at 571 nm), 9 (at 450 nm) and 5 (at 376 nm) times greater, respectively, than for the same quantities of the corresponding chlorides. The spectrophotometric determination of these elements has been investigated. Combining ratios of Tiron to rare earth have been found to be 3:2 and 2:1.     

Spectrophotofluorometric determination of terbium and europium in potassium carbonate solution

The conditions for the spectrophotofluorometric determination of terbium and europium, in solutions of potassium carbonate, have been established. The apparent excitation and fluorescence wavelengths used, respectively, are 245 mmu and 550 mmu for terbium and 400 mmu and 620 mmu for europium. The fluorescence varies linearly with the concentration of terbium and europium in the range 0.3-70 mug, of terbium/ml and 4-800 mug of europium/ml. Large amounts of gadolinium, lutetium and yttrium do not interfere. Cerium(IV) interferes seriously.     

Solvent extraction-spectrophotometric determination of rare earths with chlorophosphonazo-III

The rare-earth chlorophosphonazo III chelates are easily extracted from an aqueous solution (pH 1.1-1.5) into n-butanol. The absorbance at the absorption maximum (at 668 nm) is about 3 times that in aqueous solution. The spectrophotometric determination of rare earths has been investigated.     

The solubilities and anion-exchange behavior of rare earth elements in potassium carbonate solutions

The solubilities of rare earth elements (La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb,Lu andY) in potassium carbonate solution, and the distribution coefficients of the rare earth ions between the carbonate solution and Dowex I resin were measured. The values obtained show a variation that depends on the concentration of potassium carbonate and atomic number. There is a clearly different tendency in these values between La-Ho and Er-Lu.     

Determination of neodymium by ion-exchanger absorptiometry with the f-f electron transition band

Summary Ion-exchanger absorptiometry, based on the direct measurement of light absorption by neodymium in the cation-exchange phase, has been developed for metal determination. In the presence of ethylenediaminetetraacetic acid (EDTA) about 99% of the neodymium in a 200-ml sample solution (pH 2.2 to 2.5) was concentrated in 0.50 g Muromac 50W-X12 cation exchanger within 15 min. EDTA does not interfere with the sorption of neodymium ions on the resin but suppresses spectrophotometric interference by ferric ions and ion-exchange saturation by ferric and thorium cations. The resin-phase attenuations at 740.5 nm and of the resin background at 620 nm were used for measurements with a 5-mm cell. Neodymium in the range 0.1 – 10 mg could be simply and rapidly determined without interference from other rare earths and the proposed method was used to analyse the rare-earth minerals and alloys.

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Bestimmung von Neodym durch Ionenaustauscherharz-Absorptiometrie mit Hilfe der f-f-Elektronenübergangsbande

     

Determination of uranium(VI) in seawater by ion-exchanger phase absorptiometry with arsenazo III

An ion-exchange phase absorptiometric method with Arsenazo III has been developed for the determination of uranium (VI). A flow cell with 0.1 ml of anion exchange resin was employed to achieve a detection limit for uranium of 0.16 microg/l. in 100 ml of a seawater sample. The sensitivity is about 300 times higher than for corresponding solution spectrophotometry.