Vol. 50 No. 6
June, 2001
Takashi Hayashita, Akiyo Yamauchi, Ayako Kato*, Ai-Jun Tong**,Bradley D. Smith*** and Norio Teramae*
*Dapartment of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578
**Department of Chemistry, Tsinghua University, Beijing 100084, PR China
***Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, U.S.A.
This paper reviewed the supramolecular function of fluorescent probe/cyclodextrin (CyD) complexes for ion and molecule recognition in water. Benzo-15-crown-5 fluoroionophores, Cn-15C5 (n=1, 3, 5), with different alkyl spacer lengths were first examined to develop supramolecular Cn-15C5/γ-CyD complex sensors for alkali metal-ion recognition in water. In organic solutions, C3-15C5 shows moderate Na+selectivity based on 1:1 complex formation. However, the C3-15C5/γ-CyD complex is found to selectively respond to K+ion in water and to exhibit pyrene dimer emission. An equilibrium analysis of the γ-CyD inclusion complexes in water reveals that the major component for the dimer emission is a 2:1:1 complex of C3-15C5 with K+and γ-CyD. Although the K+sensitivity of the C5-15C5/γ-CyD complex is comparable to that of the C3-15C5/γ-CyD complex, it also responds to Na+. The fluoroionophore C1-15C5, which has the shortest methylene spacer, exhibits no response to alkali metal cations in the presence of γ-CyD. Thus, the response function is strongly affected by the alkyl spacer length of Cn-15C5, and the highest K+selectivity in water is obtained for the C3-15C5/γ-CyD complex. The boronic acid fluoroionophore C4-PB/β-CyD complex binds sugars and produces increased fluorescence emission in water. A pH-fluorescence profile for the C4-PB/β-CyD complex reveals that the fluorescence intensity increases upon the formation of the boronate conjugate base. Upon the addition of fructose, the apparent pKa decreases to a lower pH, resulting in increased fluorescence at neutral pH. The fluorescence emission response of the C4-PB/β-CyD complex upon sugar binding appears to be due to suppression of the photoinduced electron transfer (PET) from the pyrene donor to the trigonal arylboronic acid acceptor.
Keywords : supramolecular sensor; crown ether fluorophore; boronic acid fluorophore; cyclodextrin; alkali metal ion recognition; sugar recognition.
Yoshiki Sohrin*, Yukiyo Fujishima, Ayako Chiba and Tsunemi Ishita**
*Institute for Chemical Research, Kyoto University, Uji-shi, Kyoto 611-0011
**Faculty of Technology, Kanazawa University, 2-40-20, Kodatsuno, Kanazawa-shi, Ishikawa 920-8667
A method for the multi-elemental determination of ultratrace metals in seawater has been developed based on column extraction using 8-hydroxyquinoline immobilized on fluorinated metal alkoxide glass (MAF-8HQ) and determination by ICP-atomic emission spectrometry (ICP-AES) or high-resolution ICP-mass spectrometry (HR-ICP-MS). A clean technique has been realized in the method through selecting the reagents and apparatus, cleaning the apparatus, synthesizing a chelating adsorbent, and sophisticating sampling procedure, as well as filtration and concentration systems. In a preliminary concentration experiment, 34 elements were collected quantitatively from synthetic seawater of pH 5 and eluted with 0.5 M nitric acid. The measured concentrations of Co, Cu, Fe, Ni, Zn, Mo in a nearshore seawater reference material by ICP-AES after 10-fold concentration closely agreed with the certified values; the relative standard deviations were less than 8% . Lower concentrations of ultratrace metals in open ocean water were determined by HR-ICP-MS after a 10-fold concentration. Vertical profiles for Co, Cu, Fe, Ni, Zn observed in the northeast Pacific Ocean were in harmony with previous reports. The blank values for these elements have been improved to less than 0.1 nM. Since the concentrations of alkaline and alkaline earth metals in the eluate were less than 0.1% of those in seawater, this method was effective for removing sea salt.
Keywords : MAF-8HQ; ICP-AES; HR-ICP-MS; clean technique; ultratrace metals in seawater.
Kunio Takada, Tetsuya Ashino and Toshiko Itagaki*
*Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai 980-8577
(Received 10 February 2001, Accepted 18 April 2001)Received, it became possible that trace carbon in the iron and carbon adsorbed on the surface of the iron were separately determined. Similarly, a blank of sulfur was decreased for the determination of trace sulfur in iron. For determining trace oxygen, an analytical sample had to be cleaned by chemical etching in acids or electrolytic polishing. Trace amounts of Ag, Au, Se and Te were separated from major elements of an analytical sample by coprecipitation with metallic Pd as a carrier. Trace P and As were coprecipitated with Be(OH)2 in an ammonium alkaline solution. This method was applied to the separation of P and As from major elements that were masked by EDTA. Trace V, Hf, Mo, Nb, Ga, Zr and Ti were separated as cupferron complexes. Trace B and Si were separated as gaseous compounds (trimethyl borate and silicon tetrafluoride), respectively. Trace Al, Ba, Bi, Cd, Co, Cr, Cu, Mg, Mn, Ni, Pb, Ti and Zn were separated from iron that was extracted by 4-methyl-2-pentanone. The trace elements were determined by ICP-AES, graphite furnace-AAS and spectrophotometry. The determinable content of each trace element was about 0.1 µg g-1. Then, an iron sample better than 99.9987% was analyzed.
Keywords : ultra-high-purity iron; steel and alloys; ultratrace elements; chemical separation; spectrochemical analysis.
Miyuki Takenaka, Yuji Yamada, Motonaka Yabuki, Shinichi Nakamura and Shoji Kozuka*
*Corporate Research and Development Center, Toshiba Corporation, 1, Komukaitoshiba-cho, Saiwai-ku, Kawasaki 212-8582
(Received 22 January 2001, Accepted 16 March 2001)A wet chemical technique was used to dissolve the sub-area of a silicon wafer (3 to 7 cm2) to determine the ultratrace metallic elements distribution in silicon wafers in conjunction with microflow neblizer (MFN)-ICP-MS. 1 ml of etching solution with HF and HNO3 enabled the separation of several layers, such as poly-Si/SiO2 and SiO2/Si in Si wafers, evaluated by transmission electron microscope (TEM) photomicrographs. Matrix effects resulting from the etching solution were also investigated in MFN-ICP-MS. Although the interferences of F- and Si were found to be negligible, those of SO42- showed polyatomic species on 52Cr and 65Cu. The optimum etching solution and ICP-MS parameters were chosen for measurements of metallic elements in silicon samples to assess their effects on such an electronic property as time zero dielectric breakdown (TZDB) used in the fabrication of semiconductor devices. The results indicated that only 1.2×1011 atoms/cm2 of Cu significantly caused electrical damage. The limits of detection (3σ) for six metallic elements ranged from 4×109 to 5×1010 atoms/cm2.
Keywords : silicon wafer; metallic impurities; microflow neblizer-ICP-MS.
Singo Harada, Takashi Suzuki, Tethuro Sugimura, Jun Kawai*,Shinji Omori and Yoshimasa Nihei**,***
* Department of Materials Science and Engineering, Kyoto University, Yoshidahonchou, Sakyo-ku, Kyoto 606-8501
** Institute of Industrial Science, University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo 106-8558
*** Present Address, Institute of Industrial Science, University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 163-8505
We can obtain from X-ray fluorescence holography (XFH) direct three-dimensional atomic images around those atoms emitting the X-ray fluorescence, because XFH has both intensity and phase information. We measured the X-ray fluorescence intensity of a Pd (1 0 0) single crystal and investigated the polar-angle dependence after performing simulations to check the effect of the Savitzky-Golay smoothing method. We also introduce also our simulation process.
Keywords : measurement of the X-ray fluorescence intensity of a Pd (1 0 0) single crystal; investigation of the polar-angle dependence; simulation using the Savitzky-Golay smoothing method.
Tetsuya Ashino, Kunio Takada, Masaoki Oku and Kazuaki Wagatsuma*
*Institute for Materials Research, Tohoku University, 2-2-1, Katahira, Aoba-ku, Sendai 980-8577
(Received 20 January 2001, Accepted 23April 2001)For a precise and highly sensitive determination of ultratrace amounts of carbon in high-purity iron, cleaning methods of the sample surface were investigated. The cleaning methods tested were 3 kinds of chemical etching reactions (etching in HF-H2O2, electrolytic etching in acetic acid-HClO4 and etching in HCl); the effects of these cleaning on the determination of carbon were investigated. Contaminated carbon amounts, not only by adsorption on sample surface, but also by invasion inside sample, the could be removed in all cleaning methods. In etching with HF-H2O2, the lowest analytical value of carbon was obtained by using an electric tube furnace for sample combustion, while the highest analytical value was obtained for oxygen. However, the analytical values of carbon using an induction furnace were in good agreement in all methods. When samples were allowed to stand in a CO2-H2O atmosphere, the amounts of carbon adsorbed on the sample surface was found for all cleaning methods. Moreover, when etching using HCl, contaminated the carbon amounts were found not only on the surface, but also inside the sample. Only adsorbed of carbon amounts on the sample surface could be removed by heating at 623 K for 10 minutes in an ambient atmosphere. Both contaminated carbon amounts could be removed by etching in HCl.
Keywords : determination of ultratrace carbon; infrared absorption after combustion; high-purity iron; sample cleaning; X-ray photoelectron spectroscopy.
Seiko Iwata, Kazuaki Minamoto*, Eiji Fujimori, Koichi Chiba** and Hiroki Haraguchi*
*Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
**Waste Treatment Facility, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
Rare earth elements (REEs) in industrial waste incineration fly ash were determined by ICP-MS (inductively coupled plasma mass spectrometry) after LiBO2 fusion. The REEs in coal fly ash standard reference materials (NIST SRM 1633b and SRM 2691) were also determined for a comparison in a similar manner to that for industrial waste incineration fly ash. In industrial waste incineration fly ash, REEs were contained over the concentration range from 35.0 µg g-1 for Ce to 0.021 µg g-1 for Lu, which were relatively lower than those in coal fly ash. The REE distribution patterns for industrial waste incineration fly ash and coal fly ash were also examined by normalizing their concentrations with those in continental shale. They provided the characteristic distribution patterns, especially in terms of light REEs (La, Ce, Pr, Nd), Eu, and Tb in industrial waste incineration fly ash, although the distributions of REEs in coal fly ash showed some similarities to that in continental shale. In addition, the elution behaviors of REEs from industrial waste incineration fly ash were also investigated by leaching the ash sample in a 1 M HNO3 solution. The analytical results for REEs and their distribution patterns reflected a large amount of industrial usage of REEs in modern society.
Keywords : rare earth elements; industrial waste incineration fly ash; REE distribution patterns; ICP-MS; ICP-AES.
Tomokazu Tanaka, Kenji Furuhashi, Yoshio Hirooka and Masataka Hiraide*
*Department of Molecular Design and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
(Received 19 January 2001, Accepted 12 March 2001)A detachable sample-injector with a coiled tungsten filament (0.2 mm in diam.×45 mm) was constructed for the effective introduction of tiny amounts of sample into ICP-MS. A 5 µl volume of the sample was placed on a filament and an injector was inserted into a plasma torch. After desolvating the sample for 30 s with an electric current of 2.6 A, the filament was rapidly heated to ca. 2500°C by discharging a high-capacity condenser (0.54 F). The resulting vapor was transferred to the plasma with a stream of argon for the determination of As and Se. The intensities of the analytical signals increased by almost 100 times as compared with the values in a previous study, where a looped tungsten filament was electrically heated outside the plasma torch. The absolute detection limits were 0.5 pg for As and 1.1 pg for Se with relative standard deviations of 10~14%. The filament was used at least 100 times without any distortion of the signal profiles. The proposed method was applied to the determination of As and Se in certified reference human hair. The analytical results were 0.29±0.03 µg g-1 for As and 1.8±0.2 µg g-1 for Se, which are in good agreement with the certified values.
Keywords : ICP-MS; electrothermal vaporization in a torch; microsamples; arsenic; selenium.
Hiroshi Yamada, Shan Ji, Akihide Itoh*, Koichi Chiba** and Hiroki Haraguchi*
*Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
**Waste Treatment Facility, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
The simultaneous determinations of Cu, Cd and Pb in river-water samples were investigated by multielement ID (isotope dilution)/ICP-MS (inductively coupled plasma mass spectrometry). A mixed and enriched spiked solution of Cu (63Cu, 0.3%; 65Cu, 99.7%), Cd (110Cd, 0.63%; 111Cd, 96.44%; 112Cd, 1.82%; 113Cd, 0.43%; 114Cd, 0.59%; 116Cd, 0.10%) and Pb (204Pb, 0.0342%; 206Pb, 92.1497%; 207Pb, 6.5611%; 208Pb, 1.2550%) was added into the river-water samples, and kept standing overnight to achieve isotope equilibria. Since the concentrations of Cu, Cd and Pb in river water were extremely low, they were preconcentrated using a chelating resin (Chelex 100) at pH 9 before an isotope ratio measurement. The isotope ratios of 63Cu/65Cu, 114Cd/111Cd and 208Pb/206Pb were then simultaneously measured for the spiked and standard solutions, respectively. Polyatomic ion interferences of 95Mo16O and 98Mo16O with 111Cd and 114Cd, respectively, could be avoided by chelating resin preconcentration, because Mo was hardly recovered in the preconcentration, while Cd could be recovered by almost 100%. As a consequence, Cu, Cd and Pb in a river-water certified reference material (JAC 0031, issued from the Japan Society for Analytical Chemistry) and a river-water sample collected from the Kiso River were determined with fairly good precision by the present multielement ICP-MS method, simultaneously.
Keywords : river water; multielement isotope dilution analysis; ICP-MS; chelating resin preconcentration; copper; cadmium; lead.
Reiko Idegawa, Masaki Ohata, Naoki Furuta* and Kenichi Satake**
*Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551
**National Institute for Environmental Studies, 16-2, Onogawa, Tsukuba-shi, Ibaraki 305-0053
Recently, environmental pollution has become one of the most serious problems for human life. It has become very important to consider and evaluate environmental pollution from long-term perspectives. The bark and bark pockets of trees were used in this study, because these samples are influenced by air pollutants and can be used as an indicator of environmental pollution. Because the bark pocket samples were very small, the conventional sample digestion procedures could not be applied. Therefore, laser ablation/inductively coupled plasma mass spectrometry (LA/ICP-MS) was used for the determination from major to trace elements in bark and bark pocket samples in this study. From the result, it was found that the concentrations of hazardous elements, such as Sb, Pb, and Se, in bark were from a few to 100-fold higher compared to those in bark pocket produced 140 years ago. Moreover, Pb isotope ratio measurements were conducted in this study. It was also found that the Pb isotope ratios were different between bark and bark pockets that produced 70 years ago. The long-term trends of air pollution from Pb were considered based on these results.
Keywords : LA/ICP-MS; bark; bark pocket; Pb isotope ratio.
Yutaka Itabashi, Tomohisa Shoda, Koji Yamazaki and Hiroaki Okabe*
*Laboratory of Bioresouces Chemistry, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate-shi, Hokkaido 041-8611
(Received 22 January 2001, Accepted 2 March 2001)A highly sensitive high-performance liquid chromatographic (HPLC) method was developed for the separation of enantiomeric 2-hydroxy fatty acids. For this purpose, 2-hydroxy fatty acids (C14~C20) were converted to their 2-anthrylurethane and methyl ester derivatives and subjected to chiral-phase HPLC with fluorescence detection. Almost complete resolution of the racemates into enantiomers was achieved on the (R)-1-(1-naphthyl)ethylamine polymeric phase, using a ternary mobile phase, n-hexane-dichloromethane-ethanol (200:20:1 and 200:10:1, v/v/v), as the mobile phase. The formation of various hydrogen bonding, dipole-dipole stacking and charge-transfer complex between the urethane derivatives and the stationary phase was thought to contribute to the enantiomer separation. The detection limit of 2-anthrylurethanes was 1 fmol when the signal-to-noise ratio was 3:1.
Keywords : 2-hydroxy fatty acid; enantiomer; chiral-phase HPLC; 2-anthrylurethane; fluorescence detection.
Yuji Yamada, Tetsuya Tachibe*, Ayako Shimazaki**, Miyuki Takenaka and Shoji Kozuka*
*Corporate Research and Development Center, Toshiba Corporation, 1, Komukaitoshiba-cho, Saiwai-ku, Kawasaki 212-8582
**Semiconductor Company, Toshiba Corporation, 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8522
The determination of trace amounts of P and Ti on a Si wafer by high resolution ICP-MS has been investigated. Si oxide film on the wafer was decomposed by the WSA method and metallic impurities were collected into a 0.1 ml solution. A sample solution was introduced by using optimized MCN. The spectrum interference for 31P and 48Ti caused by acids and the Si matrix was removed with a mass resolution of 5000. The recoveries of P and Ti were confirmed by recovery tests using a dip method or a micro-droplet method. A comparison of proposed method and TRXRF method showed a good agreement for Ti. The detection limits for P and Ti on an 8 inch Si wafer were 3E+08 atoms/cm2 and 6E+06 atoms/cm2, respectively, and were sufficient for the evaluating actual semiconductor device manufacturing.
Keywords : silicon wafer; vapor decomposition; microconcentric nebulizer/high resolution ICP-MS; titanium; phosphorous.
Masahiro Takahashi, Ichiro Sakata and Kazuo Miyamura*
*Department of Chemistry, Faculty of Science, Science University of Tokyo, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601
(Received 19 January 2001, Accepted 3 April 2001)By measuring the tunnel-gap-width dependence of the tunnel current using scanning tunnelling microscopy, the barrier heights of a gold surface adsorbed with various metal complexes were evaluated. The barrier heights of the complex-adsorbed gold surface apparently differed from that of a non-adsorbed surface. This result indicates that a change in the electron state induced by complex adsorption can be evaluated by a barrier-height measurement. Additionally, the barrier heights of structurally different complexes were found to be different.
Keywords : STM; barrier height; Au; metal complex; characterisation.
Teiko Omori and Yuzo Yoshiike*
*Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi-shi, Chiba 274-0072
(Received 18 January, Accepted 4 April 2001)Rain and fog contaminated by air pollution cause blighted trees. Even if the concentration of contaminants is low, blighted trees are caused by the accumulation of contaminants on the leaves and bark and in the soils. Conifer-concentrated pollutants show value of about three times that of deciduous trees and the sulfuric ion in pollution matter is concentrated by about four times. The sulfuric ion is washed by rain water in the soil at the roots of a tree. When a conifer tree is living in an acid environment from the leaves to the roots it withers. The roots of a withered pine tree on a seashore contained a chloride ion value of 1780 mg/dm3 and a sulfuric ion value of 135 mg/dm3 (10 g leaf/25 g water). Consequently, the sulfuric acid forms chlorine by a chemical reaction with the sodium chloride to destroy the cells of the tree. The sulfuric acid extracts much aluminium from the soil, which is easily reactive to phosphate. Consequently, the plants can not absorb phosphorus and stop growing sprouts and wither.
Keywords : trees stand dead; blighted tree; acid rain.
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