Vol. 51 No. 2
February, 2002
Chushiro Yonezawa*
*Japan Atomic Energy Research Institute, Tokai-mura, Naka-gun, Ibaraki 319-1195
(Received 13 September 2001)A neutron-induced promptγ-ray analysis (PGA) has recently evolved as a non-destructive analytical method which can determine light elements, such as H and B, and multi-elements as a result of increased analytical sensitivities by using low-energy guided neutron beams of nuclear reactors. Firstly, the principle, characteristics and history of reactor neutron-based PGA is described; then, the characteristics of PGA systems which are classified into internal, beam and guided beam types are described. Moreover, the basics and standardization for the elemental determination in PGA are described and various applications of PGA are reviewed. Finally, micro-sample, spot and spatial-distribution analyses of elements using a cold-neutron micro beam produced by a neutron lens are described and the future development of the method is predicted.
Keywords : prompt γ-ray analysis; reactor neutron; cold neutron; thermal neutron; non-destructive analysis.
Kunihiro Watanabe, Yasuyuki Narita and Masayuki Itagaki*
* Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 4 October 2001, Accepted 21 November 2001)A continuous extraction method was investigated to remove MnII, FeIII, CoII and CuII from sodium borate as a pH buffer reagent. The removal of impurities in a reagent is very important to decrease the reagent blank value, which would determine mainly the limit of detection in analyses of metals. 5,7-Diiodooxine (HR) was used as an extraction reagent because it has a high distribution constant between the aqueous phase and chloroform. The extractabilities of metal ions by the proposed method {aqueous phase (100 cm3) and chloroform (40 cm3)} were estimated based on the metal concentration in a sodium borate solution determined by graphite-furnace AAS. In the present method, the HR concentration in chloroform was 1.0×10-3 M and the pH of the borate solution as a sample was 9.2. The organic phase containing the reagent and its metal chelates was transferred to a distillation vessel at a rate of 2.0 cm3 min-1 after separation from the aqueous phase by a Teflon phase separator in an extraction vessel under high-speed stirring. The concentration of HR in the extraction vessel was then maintained constant by the addition of a fresh HR chloroform solution at a rate of 2.0 cm3 min-1. Above 99% of the metals as impurity could be removed after 40 min of extraction. The experimental behavior of the removal of the impurity by the present method agreed with theoretical curves calculated by using an equation derived in this study. The present method was applied to sodium borate to be reagent grade. The sodium borate obtained by the purification was used as a pH buffer reagent to determine zinc by a chemiluminescence method. Furthermore, the effect of purified sodium borate on the blank value was examined by a catalytic analysis. As a result, very low values of the reagent blank were observed by each method.
Keywords : continuous solvent extraction method; sodium borate; 5,7-diiodooxine; purification; impurity.
Hironobu Yabuta, Hidekazu Miyahara, Masato Watanabe, Akitoshi Okino and Eiki Hotta*
*Department of Energy Sciences, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502
(Received 20 September 2001, Accepted 4 December 2001)We have generated and studied a stable helium ICP at atmospheric pressure using a vortex flow-enhanced torch. Though a high-power drive (more than 1 kW) is required to obtain a higher ionization ability, helium ICPs were not capable of serve as high-power drive because of melting of the quartz glass torch. In this study, to overcome this problem, a pulse-modulated ICP device, to which the continuous low and high-power pulse are applied alternately using amplitude modulation, was proposed and constructed. As a results of the pulse-modulated power drive, the applied power pulse width and frequency were limited by the rise-time of the emission pulse and melting of the plasma torch. The maximum emission intensity was about 12-times as large as that for a continuous power drive and the maximum excitation temperature also increased by about 1100 K at a peak power of 1600 W and a trough power of 400 W. Moreover, though the emission intensity and the excitation temperature for the continuous power drive were saturated with the increment of forward power, that for the pulsed power drive increased with the pulse peak power.
Keywords : helium ICP; pulse-modulated plasma.
Yuji Suzuki*, Shinya Matsu-ura, Yuji Yamauchi, Hidenobu Ohmori and Hatsuo Maeda*
*Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamada-Oka, Suita-shi, Osaka 565-0871
(Received 12 July 2001, Accepted 31 July 2001)The applicability of a resazurin/glucose dehydrogenase/β-nicotinamide adenine dinucleotide/diaphorase system as a fluorometric indicator reaction for the determination of blood glucose was explored. This indicator reaction is based on the generation of fluorescent resorufin from resazurin through an enzymatic reaction initiated by the addition of glucose. A fluorometric method with the indicator reaction afforded a calibration curve over a glucose concentration of range between 10 and 5000 µg/100 ml, and was successfully capitalized in a glucose determination of a plasma without a deproteinization procedure, where the relative standard deviation (n=10) was less than 2%. In addition, ascorbic acid, even in large excess, had almost no adverse effect on the indicator reaction. It was found that the fluorescence due to resorufin is quenched by resazurin, the extent of which depends on the concentration ratio between resorufin and resazurin: when the ratio was 1:20, the original fluorescence intensity was quenched by more than 90%. Thus, it is of great interest to give a warning that the initial concentration of resazurin is an important determinant of the sensitivity in fluorometry with the reduction of resazurin to resorufin as a general indicator reaction.
Keywords : reduction of resazurin; indicator reaction; fluorometric analysis of glucose; blood glucose; glucose dehydrogenase.
Takeshi Itoh*
*Industrial Research Institute of Nagano Prefecture, 1-18-1, Wakasato, Nagano 380-0928
(Received 20 August 2001, Accepted 17 December 2001)Acetal-copolymers are well-known engineering plastics whose excellent mechanical properties and chemical stabilities are suitable for manufacturing electronic products, automobile parts and many precision machines. Occasionally, the moldings of the copolymers deteriorate under some peculiar conditions during their storage, which, consequently reduces their original mechanical properties, and sometimes produces a reeking smell of formaldehyde. The author found that pyrograms obtained by a pyrolysis-gas chromatography method using a mass spectrophotometer as a detector (PyGC/MS) were remarkably different in their profiles between the raw material and deteriorated molding. The pyrolysis product of a deteriorated sample was specifically composed of cyclic acetals. In this report, the degradation mechanisms of this case are presumed based on the analytical results.
Keywords : polyacetals; pyrolysis-GC/MS; degradation; IR spectra.
Mitsuhiro Wada, Tsutomu Kabashima, Naotaka Kuroda, Tadashi Yoshimoto *, Hideo Katoh, Shinjiro Hayashida** and Kenichiro Nakashima***
*School of Pharmaceutical Sciences and ***Graduate School of Pharmaceutical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521
**Choko Shoyu Miso Corporation, 815 Mizooka-machi, Nagasaki 856-0844
A simple and rapid discrimination method for bacterial pollution on food is described. This method is based on a measurement of the catalase activity for bacterium on foods by a flow injection analysis (FIA) system with peroxyoxalate chemiluminescence detection. The calibration curves for five bacteria (Escherichia coli, Staphylococcus aureus, Aeromonas sobria, Pseudomonas putida and Bacillus subtilis) showed good linearities between OD600 and the chemiluminescence intensity (r≥0.951). Bacteria could be detected as low as the range of 0.02-0.12 (OD600) at 5σ of the blank peak. The proposed method is applicable to measuring the catalase activity in soup samples.
Keywords : flow injection analysis (FIA); peroxyoxalate chemiluminescence; catalase activity; food; bacterium.
Takashi Watanabe
Agricultural Chemicals Inspection Station, 2-772, Suzuki, Kodaira, Tokyo 187-0011
(Awarded by Meisei University dated March 24, 2001)A new dynamic model for predicting of pesticide concentrations in the atmosphere has been developed. The trapping method has also been studied for determining of trace pesticides in the atmosphere. Concerning trapping, the most suitable adsorbents for soil fumigants and pesticides were Porapak T and silica gel, respectively, because of their high enrichment efficiencies and high break-through volume, as well as having good stability of the adsorbed chemical species on the adsorbent. The concentrations of the pesticides, fumigants and their transformed products were measured by GC or HPLC after their dispersion over a paddy field. No transformed products, such as fenitrooxon or N-nitrosofenobucarb, were detected. After air samples at 1.5~100 m and 150~800 m in height were collected in flight with a helicopter, the concentrations of pesticides were determined with GC/MS(SIM). The volatilization rates of the pesticides, and the partition ratios of the pesticides between air/water, air/soil, air/rice leaf and air/glass surface, respectively, were measured. Afere the concentrations of the soil fumigants were measured on a soil surface, their emission ratios were calculated as the emission weight divided by the applied weight. The correlation between the volatilization rates and the physicochemical properties were analyzed. Finally, a general model to predict the concentration of pesticides in the atmosphere outside of a sprayed area was developed using the results of the measured concentrations in reference to the atmospheric diffusion model used for an air pollution prediction model.
(Received December 18, 2001)Keywords : pesticide; soil fumigant; concentration in the atmosphere; volatilization to atmosphere; atmospheric diffusion model.
Go to the page of "Bunseki
Kagaku"
Go to the top page of JSAC©2002 The Japan Society for Analytical Chemistry
All rights reserved.
26-2, Nishigotanda 1-chome, Shinagawa-ku, Tokyo 141-0031, JAPAN