Michiko Namiki

Spectrophotometric determination of micro amounts of nitrogen with organic solvent extraction: Application to metallurgical analysis

Abstract Spectrophotometric determination of nitrogen, as ammonia, with organic solvent extraction has been studied. The blue coloured compound formed from ammonia, phenol and hypochlorite (chloramine-T) is completely extracted with isobutyl alcohol or isoamyl alcohol only by using a salting-out reagent, and the optimum conditions have been established. This procedure has been applied to the determination of nitrogen in iron, steel and aluminium.

Determination of Cu3+, Bi5+ and Pb4+ in high Tc superconducting oxides by Cl2 generation, or by O2 together with Cl2 generation

SummaryFor estimating the values corresponding to the oxygen defects in high Tc superconducting oxides, iodometry has been applied for the determination of Cu3+ and Cu2+. The presence of Bi or Pb causes some difficulty in the identification of the end point of this titration, because of the formation of iodine complexes. Therefore, chlorine generation from HCl and iodometry was applied for the determination of Bi5+ or Pb4+ in the oxides, and for the additional determination of Cu3+, O2 generation was used together with Cl2 generation for Bi5+ or Pb4+.

Coherent forward scattering technique to determine copper in steels, zinc and tin

Abstract Coherent forward scattering spectroscopy having the Voigt configuration was applied in the determination of copper in steels, zinc and tin. Copper (0.0005–0.2%) in these metals could be determined without preconcentration procedure. The relative standard deviations were 4.4% for 0.0035% copper and 7.1% for 0.067% copper in steel. The reproducibility of calibration curves for copper in steels (log-log plotting with a slope of about two) was about 18% and the limit of detection was about 0.4 ± 0.07 ng/10 μl.

Coherent forward scattering spectrometry of manganese and chromium using a xenon lamp and a tellurous oxide acousto-optic tunable filter

Abstract Coherent forward scattering spectrometry has capabilities of simultaneous multielement analysis and simple instrumentation. Considering these features the authors used a xenon lamp as a continuous excitation light source and a tellurous oxide acousto-optic tunable filter as a scanning monochromator. This simple system was applied to the simultaneous determination of manganese and chromium. An analytical procedure for the determination of manganese in steels was developed and applied to standard reference materials. It was further shown that the dynamic range for both elements can be apparently extended by the use of various exciting lines and combinations of hollow cathode lamps, the xenon lamp, the tunable filter and a spectrometer.

New method for the spectrophotometric determination of ultramicro amounts of copper.

A deep yellow colour is formed by the reaction with phenol and chloramine-T in the presence of copper, and this reaction is used for the photometric determination of copper. An aqueous solution of copper and the reagents at pH 11.5-11.6 is heated. The molar absorptivity at 410 mmu, is 2.32 x 10(6). The method has been used satisfactorily to determine ultram amounts of copper in high-purity silicon.

Simultaneous determination of lead and zinc in iron and steel by cathode ray polarographic method

鉄鋼中の微量鉛および亜鉛の定量を行なうため高感度, 迅速性を有する陰極線ポーラログラフ法の研究を行ない, 支持塩の検討, 除鉄後の処理, 共存元素の影響, ピーク電位などを求め, 鉄鋼に応用した.すなわち試料を塩酸, 硝酸で分解し, 蒸発後5N塩酸酸性とし, メチルイソブチルケトンを加えて鉄を抽出除去し, 有機層に移った一部の亜鉛は6N塩酸で逆抽出し, 水層に合わせる.この溶液を蒸発し, 硝酸と過塩素酸でメチルイソブチルケトンを分解し, 乾固する.これを3度くりかえし, 冷却後0.5Mリン酸支持塩でゼラチンを添加して鉛は-0.52V (対S.C.E.), 亜鉛は, -1.17V (対S.C.E.) のピーク電位における波高を測定する.この方法によって合成試料, 実際試料中の0.00x%程度の鉛, 亜鉛の定量ができ, 標準偏差は鉛については士0.00017%, 亜鉛については±0.00063%, 変動係数は鉛は11.3%, 亜鉛は15.1%であった.本実験は鉄鋼中の鉛, 亜鉛の微量を同時定量するため陰極線ポーラログラフ法による研究を行なった.支持塩に0.5Mリン酸を用い, 主成分の鉄はMIBKで除き, MIBK抽出後, 混入してくる微量のMIBKを過塩素醜硝酸を用いて分解する.頂点電位, 測定条件を求め, さらに共存元素の影響を検討し, 微量の鉛, 亜鉛の同時定量を可能にした.これを合成試料, 実際試料に応用し, 満足すべき結果を得た.この方法によって試料の0.00x%程度の定量ができ, その精度は鉛については標準偏差±0.00017%, 変動係数11.3%, 亜鉛については標準偏差士0.00063%, 変動係数15.1%であった.