New preconcentration technique of Zr, Nb, Mo, Hf, Ta and W employing coprecipitation with Ti compounds: Its application to Lu-Hf system and sequential Pb-Sr-Nd-Sm separation

Abstract

A new preconcentration technique of Zr, Nb, Mo, Hf, Ta and W has been invented employing coprecipiation with Ti compounds. Silicate samples were digested by HF with addition of Ti. Subsequent drying with HClO 4 resulting in complete elimination of fluorine produces Ti compounds (oxide/hydroxides). The sample was then dissolved with dilute nitric acid and centrifuged, and the residual Ti compounds were collected. The Ti compounds forming from 2 mg of Ti without matrix elements concentrate 84-98% of Zr, Nb, Mo, Hf, Ta and W. In 20 mg basaltic and 50 mg peridotitic matrices, the addition of 1 mg of Ti was appropriate and gave yields of 46-69 and 54-79%, respectively, for Zr, Nb, Mo, Hf, Ta and W. Exploiting this preconcentration, sequential separation protocols of Hf, Pb, Sr, Lu, Nd and Sm for isotope analysis are developed with total blanks of 16, 11, 60, 2.4, 3 and 0.4 pg, respectively. The method is suitable for Lu-Hf system studies with capability of simultaneous separation of Pb, Sr, Nd and Sm from the same sample digest as well as isotopic anomaly studies of Zr, Mo and W. As application examples, accurate Lu-Hf data and Pb isotope ratios were obtained for basalt (JB-3) and peridotite (JP-1) by MC-ICP-MS.

Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples

“…The common availability of the instrumentation, simplicity of the procedures, speed, precision and accuracy of the technique still make flame atomic absorption method an attractive alternative [4][5][6][7]. Monitoring of trace element concentrations in biological materials, particularly biological fluids, might be considered a difficult analytical task, mostly due to the complexity of the matrix and the low concentration of these elements, which requires sensitive instrumental techniques and often a preconcentration step [8][9][10][11]. The traditional liquid-liquid extraction and other conventional separation methods are timeconsuming and labor-intensive approaches, besides requiring relatively large amounts of high-purity and frequently toxic solvents, which have to be disposed off properly.…”

A Simple and Fast Separation Method of Fe Employing Extraction Resin for Isotope Ratio Determination by Multicollector ICP-MS

“…However, in usual silicate samples, amounts of these elements compared to 1 μg Fe are <ng levels, therefore, effects of these impurities are inconsequential. Furthermore, total yields of Nb, Ta and W from the sample solution should be lower than those of the starting solution, because co-precipitation with Ti oxides of Nb, Ta and W should occur during sample evaporation using HClO 4 [19].…”

Selective Separation/Preconcentration of Silver Ion in Water by Multiwalled Carbon Nanotubes Microcolumn as a Sorbent

“…These difficulties are overcome with solid phase extraction (SPE) that has advantages of reduced analyzing time, easy manipulation, lesser amount of solvent, no disposal of large quantities of organic solvents, higher concentration factor, no problem with the miscibility of solvent, easily adaptable for very selective extraction, easy automatization, avoids problems such as incomplete phase separations, less‐than‐quantitative recoveries, and emulsion formation. This technique has been widely used for separation and preconcentration of metal ions 8–17. In SPE studies, the suitable adsorbent usage is a critical factor to get high enrichment efficiency 18.…”