Co is not coprecipitated with lanthanum hydroxide in ammonium hydroxide solution due to the formation of soluble salts of cobalt ammine complexes. This complexation reaction has been applied to the simultaneous determination of five trace impurities (As, Fe, Ti, V and Zr) in high-purity Co metal by inductively coupled plasma-atomic emission spectrometry. Warming the solution and double coprecipitation are effective for separating the trace elements simultaneously from a large amount of cobalt ammine complexes. Matrix-matched solutions are used for calibration. The detection limits of the five elements are in the range of 0.06 and 0.6 microg/g and the recoveries are quantitative.

No abstract

and Zr were separated from an iron matrix using a horizontal mini-column of an anion exchange resin. The flow of solutions through the mini-column was controlled by a peristaltic pump. The elements adsorbed on the resin were simultaneously eluted by the circulation of an eluant and determined by inductively coupled plasma-atomic emission spectrometry. Quantitative recoveries were obtained for all 7 elements in the acid-soluble fraction and for 5 elements (not B or Sn) in the acid-insoluble fraction. A part of B in the acid-insoluble fraction was lost during the ashing and the fusion but the loss was compensated by using the calibration solutions prepared with the same procedure as that for the samples. A 500-fold enrichment was obtained using this preconcentration system compared with an ordinary sample solution of 0.5 g/ 100 cm3. The proposed method was applied to the simultaneous determination of sub µg g-' levels of impurities in high purity irons. Determination of traces of impurities in high purity iron has been demanded in connection with the studies of purification and physical properties of iron.1'2 Even in the certified reference materials of high purity iron from the Iron and Steel Institute of Japan (JSS CRMs), contents of many impurities at sub µg g 1 levels have not been certified.3 Therefore, the accurate determination of these impurities is necessary. The present authors developed analytical methods of high purity irons for B4 and S5 by inductively coupled plasma-atomic emission spectrometry (ICP-AES).Extraction of the iron matrix with 4-methyl-2-pentanone was used for the simultaneous determination of traces of impurities in high purity irons followed by total reflection X-ray fluorescence (TXRF) spectrometry6, ICP-AES6 and ICP-mass spectrometry.' Relative standard deviations (RSDs) of TXRF spectrometry ranged from 12 to 29%.6 The solvent extraction method was, however, unsuitable for the separation of Cry', Mo~I, Sn'v, VV and WV! from the iron matrix because these elements were coextracted with iron.8 9Though ICP-AES is relatively sensitive to such refractory metals, preconcentration is necessary for the determination of traces of these elements in high purity iron. Ion exchange separation is useful for refractory metals. Anion and anion plus cation exchange chromatography from hydrofluoric acid have been studied for many elements.4,10-12In this paper, elution of refractory metals from a minicolumn of an anion exchange resin was studied using a peristaltic pump and circulation of an eluant. This system has advantages over a vertical column method such as minimization of the eluant and eluate, decrease in detection limit (DL), decreased analysis time, accurate control of flow rate over a wide range and rapid change of the flow rate and flow direction. This system has the possibility of being used in the flow injection analysis. Experimental ApparatusA Shimadzu (Japan) Model ICPV-1000 vacuum-type polychromator and a Model CTM-50 auxiliary monochromator were used with a sodium-treated hydrofluoric ...

No abstract

No abstract