Vol. 4 9, No. 8
August, 2000
Yasuhiro Inada*
*Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
(Received 8 March 2000, Accepted 17 April 2000)Three types of time-resolved stopped-flow extended X-ray absorption fine-structure (EXAFS) instruments have been developed by combining an EXAFS spectrometer equipped with the original time-resolved detection system and a stopped-flow unit to analyze the local structure around the metal center in short-lived reaction intermediates. The whole X-ray energy region used to obtain an EXAFS spectrum could be measured simultaneously for the instrument in the dispersive mode, and a time-resolution on the order of ms has been acheived in the case of the instrument using synchrotron radiation as an X-ray source. By using these time-resolved stopped-flow EXAFS instruments, we have analyzed the local structure around the metal center in some short-lived reaction intermediates, such as a peroxochromium intermediate formed in a reduction reaction of chromate ion by hydrogen peroxide in an acidic aqueous solution; a Cu(II)/Hg(II) heterodinuclear porphyrin intermediate formed in the Cu(II) ion incorporation process into 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin in the presence of the Hg(II) ion in water, and a chloride-bridged precursor intermediate formed in the inner-sphere reduction of CoCl(NH3)52+ by Fe2+ in N,N-dimethylformamide. According to the obtained local structure of the reaction intermediate, the reaction mechanisms and the structural characteristics of the reaction intermediates have been microscopically clarified.
Keywords : time-resolved stopped-flow EXAFS instrument; reaction intermediate; peroxochromium intermediate; Cu(II)/Hg(II) heterodinuclear porphyrin intermediate; chloride-bridged redox precursor intermediate.
Osamu Kiguchi and Katsumi Saitoh*
*Akita Prefectural Institute of Environmental Science, 191-18 Shimoyabase-Yabase, Akita 010-0975
(Received 25 February 2000, Accepted 13 April 2000)We have developed a method for the simulutaneous determination of 3 kinds of polar pesticides (methamidophos, acephate and trichlorfon) and 34 kinds of nonpolar pesticides (diazinon, chloroneb and simazine etc.) in water samples by means of solid-phase disk extraction and GC/MS. A SDB-XD Empore disk was set on a Carbon Empore disk, and a water sample of 500 ml was simulutaneously passed through it. Pesticides extracted on the disk were simulutaneously eluted with 30 ml of acetone/ethyl acetate (1:1) from the reverse side, which were obtained in good recoveries. The overall recoveries of polar and nonpolar pesticides from purified water over a concentration range of 0.0002 to 0.002 mg/l were 73 to 109% and 70 to 120%, respectively. Their mean relative standard deviations were 2.4 to 9.8% and 1.3 to 19.4%, respectively. Similar results were achieved using river water.
Keywords : simultaneous determination; solid-phase disk extraction; pesticide; GC/MS; water sample.
Mitsuyoshi Watanabe and Akira Narukawa*
*Materials Research Laboratory, Corporate R&D Group, NGK Insulators, Ltd., 2-56, Suda-cho, Mizuho-ku, Nagoya 467-8530
(Received 14 February 2000, Accepted 16 April 2000)Fluorine in sintered silicon nitride affects its strength at high temperatures. Fluorine in silicon nitride raw powder and a sintered form were separated as hydrogen fluoride by pyrohydrolysis at 1350°C and absorbed into an alkaline solution. The fluoride ion concentration in the solution was then measured by ion chromatography. Prior to hydrolysis, the sintered silicon nitride was pulverized to below 149 µm to secure the complete removal of fluorine during pyrohydrolysis. The proposed method required 3hrs per sample with a detection limit of 1 µg F g-1 and a relative standard deviation of <5% for raw powder and <2% for sintered silicon nitride.
Keywords : silicon nitride; fluorine; pyrohydrolysis; IC; XRF.
Kaoru Yamada, Shigeaki Matsutani, Yasunobu Horiguchi* and Toshiyuki Hobo**
*Lion Corporation, 7-13-12, Hirai, Edogawa-ku, Tokyo 132-0035
**Department of Applied Chemistry, Graduate School of Engineering, Tokyo Metropolitan University, 1-1, Minami-Ohsawa, Hachioji-shi, Tokyo 192-0397
A simple and rapid method using HPLC with postcolumn detection has been developed for the separation and determination of a peroxide mixture. A hydrogen peroxide(H2O2), methylhydroperoxide(MHP) and peroxosulfate mixture was chosen for the sample. LC separation was carried out on an Inertsil ODS-2 column(4.6 mm i.d.×250 mm length) using pH-adjusted distilled water with H3PO4 as the mobile phase at a flow rate of 1 ml/min. An oxidizing reaction of I- by peroxide was applied to the postcolumn reaction. Thus, a 10% KI aq. solution at a flow rate of 0.5 ml/min was used as the reaction solution. Teflon tubing (0.5 mm i.d.×10 m length) was used as a reaction coil at 90°C. UV detection was performed at 348nm. The detection limits (S/N=3) for H2O2 and MHP were 35 ppb and 50 ppb, respectively. Under this analytical condition, peroxides and I- reacted quantitatively. Thus, the determination of various kinds of peroxides is possible by comparing the peak areas with that of a H2O2 standard solution, even if the standard substance of the peroxides is not available. Since the proposed system uses only easily available apparatus and reagents, this method is suitable for process control.
Keywords : HPLC; peroxides; postcolumn detection; hydrogen peroxide; triiodide ion.
Bunbunoshin Tomiyasu**, Masanori Owari*** and Yoshimasa Nihei**
**Institute of Industrial Science, The University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo 106-8558
***Environmental Science Center, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033
We have investigated the cause of an uncertainty in the quantitative analysis for micro-particles using secondary ion mass spectrometry (SIMS) as a destructive local analysis. From a comparison between the uncertainty using a simultaneous multi-elements detection system with a gallium-focused ion beam (Ga-FIB) SIMS and the uncertainty using a single-channel detection system with a conventional SIMS, the effect of a multi-elements detection system for decreasing the uncertainty of quantitative measurements was estimated. It was clear that the uncertainty of a quantitative analysis for a micro-particle using a Ga-FIB SIMS measurement was 4.5%, and the uncertainty based on the reproducibility of magnetic field was 7.0%; the uncertainty based on changes of the analyzed surface with time was 9.9%~17.8%. From these results, the uncertainty based on a single-channel detection system, which was the composite uncertainty based on the reproducibility of the magnetic field and the changes of the analyzed surface with time, was calculated to be 12.1%~19.1%. We thus conclude that the multi-elements measurement system improves the analytical reliability by 12.1%~19.1%.
Keywords : analytical reliability; uncertainty of quantitative analysis; simultaneous multi-elements measurement; gallium focused ion beam; secondary ion mass spectrometry.
Kunihiro Watanabe, Masahiko Shiba and Masayuki Itagaki*
*Department of Industrial Chemistry, Faculty of Science and Technology, Science University of Tokyo, 2641, Yamazaki, Noda-shi, Chiba 278-8510
(Received 21 March 2000, Accepted 16 May 2000)To remove impurities from a reagent is very important in the field of microanalyses. 2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid (NANA) is an excelent reagent used for the catalytic analysis of manganese(II). The detection limit for the determination of manganese(II) with NANA was 0.15 ppt. However, an improvement in the sensitivity for the determination of manganese(II) was expected by purifying of NANA as an indicater reagent. A wide variety of methods have been proposed and used for the purification of reagents; liquid-liquid extraction is the most extensively used method. In this paper, the condition for removing manganese(II) from NANA by the simultaneous forward and back-extraction method is examined for purpose of purifying NANA. This method is similar to a liquid-membrane method (uphill transport). 5,7-Diiodooxine was used as an extraction reagent because it has a large distribution ratio. Five micrograms of manganese(II) were recovered perfectly from 100 ml of a 1.2×10-3 M-NANA solution with 1.5 M-HNO3 solvent at a stirring time of 40 min under the optimum conditions. Furthermore, purified NANA was applied to a catalytic analysis. The color-fading rate [ln(A1/A10)] of unpurified NANA was 0.061 and that of purified NANA was 0.038, where A1 and A10 are the absorbances of NANA at 1 min and 10 min after starting the reaction, respectively. Since ln(A1/A10) is proportional to the manganese(II) concentration; it was been confirmed that manganese(II) in NANA was removed. When purified NANA was used, the calibration curve of manganese(II) was liner over the range 0~2 ppt, and its detection limit was 0.10 ppt. It was greatly improved compared to the conventional procedure.
Keywords : simultaneous forward and back-extraction method; removal of manganese impurity; 5,7-diiodooxine; 2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthyazo)-3-naphthoic acid.
Sonomi Kushibe and Norikuni Yabumoto*
*Materials Development and Analytical Technology Center, NTT Advanced Technology Corporation, 3-1, Morinosato-Wakamiya, Atsugi-shi, Kanagawa 243-0198
(Received 28 February 2000, Accepted 12 April 2000)A handy analytical method with high sensitivity for trace sodium which intrudes into metal films on silicon wafers is reported. Mixed solutions based on diluted hydrofluoric acid decomposed AlSiCu, Ti, and WSi3 films, which were applied to the interconnection of LSI, making the Si surface hydrophobic. Consequently, the decomposed droplet could be recovered easily. The droplet was analyzed by graphite-furnace atomic-absorption spectrometry. Detection limits of Na for the metal films were (3~4)×1015 atoms/cm-3. The recovery rates of Al, Ti, and W of metal films and Na in them were more than 99%.
Keywords : metal film; silicon wafer; sodium; sensitive determination; graphite-furnace AAS.
Yoshimi Hashimoto, Masaru Hayashi* and Akira Okada**
*Research and Development Center, Toshiba Corporation, 1, Komukai Toshiba-cho, Saiwai-ku, Kawasaki 212-8582
**Research and Development Center, Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8522
The determination of trace amounts of anions in organic materials for ultra large scale integration (ULSI) using pretreatment methods coupled with ion chromatography was examined. An alkaline fusion method was applied for the total anion impurity content. A hot-water extraction method was applied for ionic impurities at the surface and the inside of materials. An acetone extraction method was used for ionic impurities in the remaining flux. A trichloromethane-water back-extraction method was applied for liquid samples, such as oil and photo-resist materials. An alkaline fusion method brought, sodium and bicarbonate ions in the system. Because the matrixes influenced the chromatography, a removal method was assessed using cation exchange and nitrogen bubbling. By combining four kinds of pretreaments and ion chromagrapy, determinations at the ppb level of anionic impurities in various organic materials for ULSI could be carried out.
Keywords : ion chromatography; trace analysis; organic materials; anion impurities; ULSI.
Naoto Minakawa, Katsuyuki Takahashi, Yasushi Nagamune and Junichi Sasaki**
**Green Blue Corp., 5-4-1, Higashikoujiya, Ohta-Ku, Tokyo 144-0033
(Received 21 March 2000, Accepted 18 June 2000)After calibrating the flow meters of Andersen samplers, suspended particulate matters was collected separately according to particulate size with 8 different samplers to examine the compatibility of the measurement data. The 8 Andersen samplers used for a field analysis showed an average of 55.4±2.33 µg/m3 of the concentration of suspended particulates and a coefficient of variation of 4.2%. The suspended particulates were measured along Loop 8 in Tokyo, and their behavior from the roadside was examined according to the particulate size. Their concentration decreased at 100 m from the roadside by 33% in the summer and by approximately 20% in other seasons. The concentration of coarse particulates (2.1 to 11.0 µm) decreased at 25 m from the roadside, but showed no seasonal variation. However, the concentration of fine particulates (<2.1 µm) decreased in all seasons in a similar manner of the suspended particulate. The ratio of coarse particulates to fine particulates was about 1:2.
Keywords : suspended particulate matters; calibration of flow rate; accuracy of concentration; decrement of concentration with distance.
Naoto Minakawa, Katsuyuki Takahashi, Yasushi Nagamune, Nobuyuki Koide** and Kenji Seo***
**Green Blue Corp., 5-4-1, Higashikoujiya, Ohta-Ku, Tokyo 144-0033
***OS-Lab. Corp., 1-14-12, Nishikanagawa, Kanagawa-Ku, Yokohama 221-0822
After automatic nitrogen oxide analyzers were calibrated, nitrogen oxides in the air were analyzed in the field by 14 calibrated automatic analyzers to examine the compatibility of measurement data. The 14 analyzers, calibrated with an equivalent liquid (static), showed nearly identical coefficients of variation over the range of 0.3 to 1.2%. However, those calibrated with a standard gas (dynamic) showed 99.7±0.35% of the collection rate of nitrogen dioxide (NO2) and 79.2±2.7% of the oxidation rate of nitrogen monoxide (NO) and 3.4% of the coefficient of variation, similar to that in the static calibration. The same air sample was introduced into the 14 analyzers for 24h for a comparison. A mean NO concentration of 11±0.55 ppb with a coefficient of variation of 5.0%, and mean NO2 concentration of 25±0.53 ppb with coefficient of variation of 2.1% were achieved, respectively. The concentration of nitrogen oxides was analyzed at the same time around Route 1 (traffic: 60000 vehicle/day), a typical principal road in the Metropolitan area, in all seasons by the 14 analyzers mentioned above. The concentration of NO2 was nearly the same at 0 m and 150 m from the road side during all seasons, but was slightly lower in the summer. On the contrary, the mean concentration of NO during 2 weeks was 75 ppb at 0 m and approximately 40 ppb at 50 m or more from the roadside in the winter. A direct effect of NO emitted from the vehicles on the NO concentration was obserbed at a distance of up to 50 m.
Keywords : concentration of nitrogen oxides; static calibration of analyzers; dynamic calibration of analyzers; performance test of analyzers; contribution of nitrogen oxide concentration from road.
Tohru Saitoh*, Yoko Hamazono, Teruaki Sakurai and Chiyo Matsubara**
*Department of Molecular Design and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603.
**Tokyo University of Pharmacy and Life Science, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392
Lipopolysaccharides (LPS) were successfully extracted from water by polymer-mediated extraction based on the thermoresponsive precipitation of a water-soluble polymer: poly (N-isopropylacrylamide) [PNIPAAm] in aqueous solutions. LPS, having a hydrophobic lipid moiety and hydrophilic polysaccharides, were less extractive than lipids, but well concentrated to the small volume of the aggregated polymer precipitates (polymer phase). In contrast, hydrophilic compounds, including saccharides, urea, creatinine, serum proteins, and inorganic ions, hardly incorporated into the polymer phase. Collected LPS could be recovered to a chitosan bead column by passing through an aqueous PNIPAAm solution of LPS.
Keywords : thermoresponsive polymer; N-isopropylacrylamide; lipopolysaccharides; extraction.
Takuro Watanabe and Kenji Kato**
**National Institute of Materials and Chemical Research, 1-1, Higashi, Tsukuba-shi, Ibaraki 305-8565
(Received 2 February 2000, Accepted 22 May 2000)Nine volatile organic compounds (VOCs) (vinyl chloride, 1,3-butadiene, acrylonitrile, dichloromethane, chloroform, 1,2-dichloroethane, benzene, trichloroethylene, tetrachloroethylene) mixed calibration gases at the ppt level were prepared by gravimetric dilution from commercial VOC calibration gas (100 ppb). Ordinaly canisters (6 l) were used as diluting vessels. The uncertainty of the prepared 10 ppt calibration gas was about 3.8% including the uncertainty of the source gas. Diluted gases were analyzed by GC/MS with a three-stage preconcentrator. The relations between the calculated concentration (10 ppt to 100 ppb) and analytical values of GC/MS measurements showed good linearity (r2=0.9972~0.9999) for all nine VOCs.
Keywords : canister; gravimetric dilution; calibration gas; low concentration; volatile organic compound.
Harumi Takei and Fumihiko Yoshizaki*
*Tohoku Pharmaceutical University, 4-1, Komatsushima 4-chome, Aoba-ku, Sendai 981-8558
(Received 3 March 2000, Accepted 20 April 2000)The determination of flavanone glycosides in various peels of Citrus fruits, immature Citrus fruits and Chinese medicinal prescriptions containing these crude drugs was performed by using capillary electrophoresis. The analytical procedure employed in this experiment seemed to be useful for the evaluation and quality control of these two crude drugs, but was applicable for estimating flavanone glycosides in only a few Chinese medicinal prescriptions.
Keywords : capillary electrophoresis; flavanone glycosides; peel of Citrus fruit; immature Citrus fruit; Chinese medicinal prescription.
Tomoyoshi Soga
Yokogawa Analytical Systems Inc., Application Center, 2-11-13, Nakacho, Musashino-shi, Tokyo 180-0006
(Awarded by Toyohashi University of Technology dated March 8, 2000)Simultaneous determination methods for anions were studied by capillary electrophoresis (CE). First, a CE method for the analysis of inorganic and organic anions which have UV absorbance was developed by using a polymer-coated capillary. Next, CE methods for anions having little or no UV absorption were described. Each method was performed with indirect UV detection using 2,6-pyridinedicarboxylic acid (PDC) and cetyltrimethylammonium salt as the background electrolyte (BGE). To avoid the adsorption of organic acids on the capillary, high complexing ability with metals was necessary for the BGE. The use of PDC provided a good sensitivity of organic acids. 28 carbohydrates, such as acidic, neutral, amino sugars and sugar alcohols, could be analyzed with the same BGE at a pH of 12.1. Its utility was demonstrated in an analysis of monosaccharides of hydrolyzed glycoprotein and food samples. The high complex ability of PDC also enabled the simultaneous analysis of inorganic and organic anions, as well as metal cations. The PDC worked to confer a negative charge on metal cations via PDC-complex formation. Furthermore, this BGE system was evolved into the simultaneous analysis of 43 inorganic anions, organic acids, amino acids and carbohydrates and applied to the analysis of those compounds in food samples.
(Received 29 May, 2000)Keywords : capillary electrophoresis; 2,6-pyridinedicarboxylic acid; indirect UV detection; inorganic anion; organic acid; carbohydrate; amino acid.
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