Akio Hirose

Determination of rare earth elements and heavy metals in river water by preconcentration on chelex 100 and neutron activation

Abstract The neutron activation determination of rare earth elements and heavy metals in river water has been studied with Chelex 100 resin as a preconcentration agent. The resin is applied directly as a support for irradiation and for radiochemical separation. The radioactive rare earth elements are recovered selectively and quantitatively from the irradiated resin by elution with hot 1 M sodium carbonate solution; radioactive heavy metals are recovered with 2 M nitric acid. Activities from each eluate are counted with a Ge(Li) detector connected to a multichannel analyzer; La, Sm, Eu, Dy, Mn, Cu and Zn can be determined. The recoveries were almost quantitative and the measurement of chemical yield was unnecessary.

Studies on micro high-performance liquid cromatography : V. Design of a microscale liquid chromatograph and its application to cation-exchange separation of alkali metals

Abstract A microscle liquid chromatograph has been designed and optimized by estimating band broadenings. The high-performance cation-exchange resin, Hitachi No. 2610, was packed into the column, and applied to the separation of alkali metals by radioactivity detection. Four alkali metals were separated within 26 min. using only 208 μl of 0.7 N hydrochloric acid as carrier solution.

Cation exchange separation of 16 rare earth metals by microscale high-performance liquid chromatography

The separation of rare earth metals has been studied with a micro-column of 0.5 mm i.d.×75 mm length, packed with TSK LS-212 high-performance cation exchange resin 16 rare earth metals were separated within 38 min, using only 304 μl of 0.4M α-hydroxyisobutyric acid solution adjusted to pH 3.1–6.0 with ammonia solution as gradient carrier solution. The gradient elution was successfully performed by applying a new technique developed for microscale liquid chromatography.

Application of microscale liquid chromatographic technique to the anion exchange separation of halide ions

The microscale liquid chromatograph used in the present work is as follows: injection volume of sample 0.2–0.9 μl; column 0.5 mm i.d x 12–59 mm; connecting tube between column and detection cell 0.25 or 0.5 mm i.d. x 20 mm; detection cell 0.25 or 0.5 mm i.d. x 8 mm. The high performance anion exchange resin, TSK LS-222, was loadd in the column, and applied to the separation of halide ions. Three halides, Cl−, Br− and I− have been separated with a column of 59 mm length within 19 min, using only 152 μl of 1.5N sodium nitrate-acetone (1:1) mixture as carrier solution. When the element of interest is only iodine, it could be separated from the other halides with a column of 12 mm length within 4.5 min. Some fundamental studies for HETP and capacity factor are presented.

Multiple detection system for the high-resolution microcolumn size-exclusion chromatographic separation of proteins with a slurry-packed capillary column

A multiple (triple) detection system with one detector and recorder each was developed for the high-resolution size-exclusion chromatographic separation of proteins with a slurry packed capillary column. Fused-silica capillary columns of length 1, 2.5 and 6 m and I.D. 0.26 mm were connected in this order by joining each end of the shorter column to the top of the longer column through flow-through cells installed side-by-side on a cell block in the detector. By this means it was possible to record the chromatograms three times with one injection. This system is convenient for comparing the chromatograms obtained with different plate numbers and for effecting very high-resolution separations.

Microcolumn chromatofocusing : III. Effect of the analysis time on the resolution and the use of a semi-disposable microcolumn

Abstract By using a DEAE anion exchanger and Ampholine or Polybuffer 96 as buffer, chromatofocusing separations of proteins have been studied. The resolution differs according to the analysis time and the best is obtained in the first analysis. The difference between the first and the second analyses was large, but subsequent differences were small. The decrease in efficiency is due to the buffer solutions of carrier ampholytes used, not to the protein injected. The column of decreased efficiency could not be regenerated by washing. Therefore, the use of a semi-disposable microcolumn is proposed. The cost of the microcolumn is very low, so that such use would be feasible in microcolumn liquid chromatography.

Multielement profiling analysis of geochemical and environmental samples by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS)

Simultaneous multielement analysis of geochemical and environmental samples such as rock, sediment, seawater, and lake water have been carried out by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). In these experiments, some instrumental improvement and sample pretreatment techniques were required to fulfil accurate multielement determination of 30-50 elements for each sample described above. Consequently, it becomes possible to characterize the samples by comparing the profiles of their multielement concentration distributions. Such multielement profiling analysis of various samples may be useful in the research fields such as geochemistry, environmental chemistry, material science and so forth.<<ETX>>

Thermal neutron activation analysis of hafnium in zircaloy with a Van de Graaff accelerator

Thermal neutron activation analysis of hafnium in zircaloy was investigated with a Van de Graaff accelerator. Thermal neutrons were obtained by moderating Be−D fast neutrons with paraffin blocks.179mHf isotope with a half-life of 18.6 s, produced by178Hf(n, γ)179mHf reaction, was utilized in the present analysis. This method made it possible to analyze hafnium rapidly and non-destructively by using scandium as an internal standard material. Several tens to hundreds of ppm of hafnium in zircaloy samples were determined within 2 minutes with a precision of about ±1%.