Tatsuya Seki

Determination of traces of palladium in stream sediment and auto catalyst by FI-ICP-OES using on-line separation and preconcentration with QuadraSil TA.

A flow injection analysis (FIA) method using on-line separation and preconcentration with a novel metal scavenger beads, QuadraSil TA, has been developed for the ICP-OES determination of traces of palladium. QuadraSil TA contains diethylenetriamine as a functional group on spherical silica beads and shows the highest selectivity for Pd(II) at pH 1 (0.1 mol l(-1) hydrochloric acid) solution. An aliquot of the sample solution prepared as 0.1 mol l(-1) in hydrochloric acid was passed through the QuadraSil TA column. After washing the column with the carrier solution, the Pd(II) retained on the column was eluted with 0.05 mol l(-1) thiourea solution and the eluate was directly introduced into an ICP-OES. The proposed method was successfully applied to the determination of traces of palladium in JSd-2 stream sediment certified reference material [0.019+/-0.001 microg g(-1) (n=3); provisional value: 0.0212 microg g(-1)] and SRM 2556 used auto catalyst certified reference material [315+/-4 microg g(-1) (n=4); certified value: 326 microg g(-1)]. The detection limit (3 sigma) of 0.28 ng ml(-1) was obtained for 5 ml of sample solution. The sample through puts for 5 ml and 100 microl of the sample solutions were 10 and 15 h(-1), respectively.

Online determination of copper in aluminum alloy by microchip solvent extraction using isotope dilution ICP-MS method

Isotope dilution mass spectroscopy (IDMS)/ICP-MS combined with microchip solvent extraction was successfully applied for the online determination of copper in an aluminum alloy. The microchip solvent extraction was developed for the separation of Cu from major element, and optimal pH range was wider than that of the batchwise extraction method. The dimensions of the microchip were 30 mm x 70 mm and that of micro-channel on the microchip was 180 microm wide and 40 microm deep. The copper complex with 8-hydroxyquinoline was extracted into o-xylene at pH 5.5 and back extracted with 0.1 mol l(-1) nitric acid at flow rate of 20 microl min(-1). The total extraction efficiency (water/organic solvent/nitric acid) was around 40%. IDMS/ICP-MS was coupled with solvent extraction for precise determination of Cu. The extraction and back-extraction on the microchip took about 1s and the total measurement time for the IDMS/ICP-MS was about 40s/sample. The blank value of this method was 0.1 ng g(-1). The proposed method was used for the determination of Cu in Al standard materials (JSAC 0121-C, The Japan Society for Analytical Chemistry and 7074 Al alloy, Nippon Light Metal Co. Ltd.). The obtained analytical results are in good agreement with the certified values.

Anion-exchange behaviour and separation of metal ions on deae-cellulose in oxalic acid media

The anion-exchange behaviour of 30 metal ions on a weakly basic ion-exchanger (DEAE-cellulose) has been investigated in aqueous oxalic acid media over the concentration range 0.0010-0.50 M. There are marked differences in adsorbability between ter- and quadrivalent metal and bivalent metal groups; the system offers good prospects for group separations. The adsorptions are moderate, generally a few orders of magnitude lower than those on Dowex 1 (a strongly basic resin). Procedures for the separations Se(IV)Se(VI); As(III)As(V); multicomponent separations Mn(II)Co(II)Cu(II)Ti(IV)Zr(IV) and Cd(II)Zn(II)Cu(II), are given to demonstrate the versatility of the system.

Anion-exchange system in magnesium nitrate media. Application to chemical analysis of manganese nodules for thorium and uranium

ZusammenfassungDas Adsorptionsverhalten von 26 Metallionen wurde aus Magnesiumnitratlösung an dem stark basischen Anionenaustauscher Bio-Rad AG-1, X-8, untersucht. Die Salzkonzentration reichte von 0,5-3,0 M bei Gegenwart von 0,1 M freier Salpetersäure. Die Verteilungskoeffizienten von Bismut(III), Thorium(IV) und Uran(VI) reichen bei hoher Salzkonzentration bis zur Größenordnung von 1000, wogegen die meisten anderen Elemente nur schwach adsorbiert werden, was auch in reiner salpetersaurer Lösung der Fall ist. Dadurch können Th(IV) und U(VI) gleichzeitig aus 2,5 M Nitratlösung angereichert und mit gutem Erfolg in Manganknollen bestimmt werden, wobei nur eine einzige Elution von einer kleinen Harzsäule erforderlich ist. Die anschließende Bestimmung erfolgt spektralphotometrisch mit Arsenazo III.SummaryThe adsorption behaviour of 26 metal ions on the strongly basic anion-exchange resin Bio Rad AG-1, X-8 has been examined in magnesium nitrate media. The salt concentration range from 0.50-3.0 M is covered in the presence of 0.1 M free nitric acid. The distribution coefficients of bismuth(III), thorium(IV) and uranium(VI) rise to the order of 1,000 in media of 0.1 M nitric acid with high salt strength, while most other elements are only weakly adsorbed as is also the case in pure nitric acid media. The system allows thorium(IV) and uranium(VI) to be concentrated simultaneously from 2.5 M nitrate media, so that it can be applied successfully to the determination of thorium and uranium in manganese nodules with consecutive Chromatographic elution from a single small resin column. The subsequent determination is carried out spectrophotometrically with Arsenazo III.

Accurate determination of cobalt in silicate rocks by a combined cation-exchange separation — Atomic absorption spectrophotometry

ZusammenfassungBei dem beschriebenen kombinierten Verfahren wird die Probe mit Perchlorsäure/Flußsäure aufgeschlossen und der Rückstand in einer Lösung von 0,5 M Salzsäure, 0,05 M Oxalsäure und 1,5% Wasserstoffperoxid auf die Austauschersäule gegeben (Bio-Rad AG 50W, X-8, H-Form). Mehrwertige Ionen einschließlich Eisen werden nicht absorbiert, während Cobalt zusammen mit Erdalkalien und Aluminium zurückgehalten wird. Cobalt kann dann selektiv mit 1 M Salzsäure in 84% Aceton eluiert und anschließend mit AAS bestimmt werden. Das beschriebene Verfahren gestattet die Abtrennung von Cobalt aus komplizierten Matrices mit für die AAS-Bestimmung ausreichender Selektivität. Belegwerte für internationale Standardgesteine und metallisches Eisen werden angegeben.SummaryA combined cation-exchange separation — atomic absorption spectrophotometric method is described for the determination of cobalt in silicate rocks. Silicate is decomposed with a mixture of perchloric acid — hydrofluoric acid. The residue is fed on a Bio-Rad AG 50W, X-8 resin (hydrogen form) column from 0.5 M hydrochloric acid — 0.05 M oxalic acid — 1.5% hydrogen peroxide solution. Polyvalent ions including ferric ions are not adsorbed on the column, while cobalt is retained together with alkaline earths and aluminium. Then, cobalt can be stripped selectively by elution with 1 M hydrochloric acid in 84% acetone solution and can subsequently be determined by AAS. The single column ion-exchange method described allows cobalt to be isolated from complicated matrices with good selectivity, sufficient enough to permit the final determination spectrophotometrically. Quantitative results are presented for the determination of cobalt in international rock standards and iron metal.