Simultaneous Determination of Sub μg g−1 Levels of Impurities in High Purity Iron by Inductively Coupled Plasma-Atomic Emission Spectrometry after Circulation of Eluant through Anion Exchange Resin Mini-Column

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 ...

Removal of an Iron Matrix with Polyoxyethylene-Type Surfactant-Coated Amberlite XAD-4 for the Determination of Trace Impurities in High-Purity Iron

“…Ion-exchange separation is also frequently performed for the separation of trace analytes from an iron matrix and does not require organic solvents. − However, highly hazardous hydrofluoric acid is often required for sufficient separation. − Alternatively, masking an iron matrix with a large amount of complexing agents, such as oxalate 17 and ethylenediamine- N,N,N ‘ ,N ‘ -tetraacetate, is sometimes performed, which potentially causes appreciable contamination. Coprecipitation is another organic solvent-free technique and is occasionally employed for preconcentrating trace elements in high-purity iron. ,, However, a large amount of coprecipitant is, in turn, introduced into analytical instruments.…”

Determination of Trace Amounts of Boron in Steel by Reversedphase High-Performance Liquid Chromatography with Azomethine-H as a Precolumn Derivatizaion Agent

“…The lower limit of the determination, defined as 10 times of the standard deviation of the blank signal (10σ), was 3.3 × 10 -8 mol dm -3 . This value is converted in 0.09 µgB/g on a steel sample base, which is almost equal to the lower limit of the determination of an isotope-dilution ICP-MS. 7 The repeatability (relative standard deviation) of the present method was 1.7% for 5 replicated analyses of a solution containing 2 × 10 -6 mol dm -3 of boron.…”

“…Recent analytical works on steel have centered on inductively coupled plasma atomic emission spectrometry (ICP-AES) [3][4][5][6][7] and inductively coupled plasma mass spectrometry (ICP-MS). 8,9 However, these methods are not always the most suitable for the determination of trace amounts of boron in steel materials requiring the preconcentration of boron and a matrix removal, because of their insufficient sensitivities for boron.…”

Determination of Ti, V, Zr, Nb, Mo and Ta in High-Purity Iron Using Cupferron Co-Precipitation Separation by Axially Viewed ICP-AES with Ultrasonic Nebulization System and a Long Torch

“…Quantitative trace element analyses have previously been carried out primarily by inductively coupled plasma atomic emission spectroscopy (ICP-AES). 2) Highly sensitive inductively coupled plasma mass spectroscopy (ICP-MS) [3][4][5] has recently come to be used as an alternative, because it is considered more suitable for trace analysis. However, it is affected significantly by the iron matrix, and various influences on the MS interface section 6,7) can induce substantial deviations of the determined values.…”