Vol. 52 No. 5
May, 2003
Kiyoshi Teranishi1, Kimio Isomura1, Miho Yano1, Haruo Tsuji2, Kenji Chayama2, Sinjiro Fujiwara2, Kazuya Yao2 and Hidehiro Utida2
1 Hyogo Prefectural Institute of Health and Environmental Science, 2-1 Arata-cho, Nagata-ku, Kobe-shi, Hyogo 652-0032(Received 1 November 2002, Accepted 18 February 2003)
Rare earth elements (REEs) in Arima-type spring waters were detemined by ICP-MS after pre-concentration with a chelating resin. Our previously reported method was improved by washing the chelating resin with 5 M HCl over night and then removing the mass interference of Ba to Eu-151. The concentrations of REEs in a hot spring of high Cl content are relatively low compared with a low temperature spring of high Cl and CO2 contents. The correlation of all the REEs concentration, except for the Eu and CO2 concentration, were found in Arima spring water samples. Thus the carbonate species plays an important role in the REEs contents in these Arima spring water samples. From the chondrite pattern of the REEs, a positive Eu anomaly was observed in all hot spring samples of high Cl and Fe contents in the Arima region. Also the concentration of Eu was correlated with the K concentration in the Arima spring water samples. Eu in spring water was stimulated to be dissociate into the Eu2+ ion from the feldspa of wall-rock by a hot water/rock interaction at reduction situation.
Keywords : rare earth elements; Arima type spring water; positive Eu anomaly; ICP-MS; chelating resin.
Kazuhiro Shikakume1, Yukio Yokoyama2 and Hisakuni Sato3
1 Chemical Standards Department, Tokyo Laboratory, Chemicals Evaluation and Research Institute, Japan, 1600 Shimo-Takano, Sugito-machi, Kitakatsushika-gun, Saitama 345-0043(Received 14 November 2002, Accepted 20 February 2003)
The linearity of the regression line for the calibration in anion determination by ion chromatography with a suppressed conductivity detector was studied both theoretically and experimentally. The relationships between the peak area and the concentration of standard solutions were obtained by equilibrium calculations for fluoride, chloride, nitrate and sulphate ions. Theoretical calculations assuming that the non-linearity of the calibration line can be attributed to a shift of the acid-base equilibrium of the solute and eluent ions are consistent with experimental data. Generally, the calibration line is not linear for the anions of a weak acid, such as fluoride ion. Some eluents, such as carbonate salt, give a curved regression line for any solute ions. For a high-precision calibration, the linear regression should be limited to a narrow concentration range because of the non-homogeneous precision of the conductivity measurement. The high order of the regression formula, if necessary, should be adjusted to the data group of the homogeneous precision. Numerical examples of the linear calibration range are shown for fluoride, chloride, nitrate and sulfate ions.
Keywords : ion-chromatography; suppressed conductivity detection; linearity of calibration; homogeneous precision.
Ryoji Nakajima1, Takashi Yarita2 and Masami Shibukawa1
1 College of Industrial Technology, Nihon University, Izumi, Narashino-shi, Chiba 275-8575(Received 19 November 2002, Accepted 21 February 2003)
A method for the superheated water chromatography (SWC)-flame ionization detection (FID) of alcohols was developed. An FID system was connected to an SWC system by splitting the mobile phase of the SWC system and then introducing it into the FID system via a fused-silica capillary tube. The FID conditions (the position of the end of the capillary tube in the FID system, flow rate of hydrogen gas, and flow rate of helium makeup gas) were optimized so as to obtain a stable and sensitive detection of alcohols; the detection limits (S/N=3) of methanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol were in the range of 26~57 ng (as injected amounts into the SWC system) under the optimized conditions. The retention of alcohols in SWC decreased with an elevation in the column temperature as well as a decrease in the mobile-phase pressure. The retention mechanism was characterized using a thermodynamic theory that has been used for describing retention in conventional high-performance liquid chromatography. The application of the present method to determination of ethanol in wine samples was also demonstrated, in which the observed values were comparable to those obtained by gas chromatography/mass spectrometry.
Keywords : superheated water chromatography; superheated water; flame ionization detection; alcohols; wine.
Eiji Fujii1, Katsuhiko Shimizu1, Yu-ki Kurokawa1, Aki Endo1, Shin-ichi Sasaki1,4, Kazuyoshi Kurihara2, Daniel Citterio2, Hiroki Yamazaki3 and Koji Suzuki1,2
1 Department of Applied Chemistry, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagwa 223-8522(Received 7 October 2002, Accepted 28 February 2003)
The determination of glycosylated albumin (GA) based on an SPR apparatus was performed using the bond formation of GA with boronic acid functional groups on a sensor chip. In order to develop a sensor chip that can reduce non-specific adsorption, the surfaces of gold-evaporated chips were chemically modified by forming self-assembled monolayers (SAMs) of five kinds of thiol compounds. It was confirmed that the sensor chip modified with an ethylene glycol (EG) terminated SAM showed the best results for reducing non-specific adsorption among the examined SAMs. It was found that the sensor chip can reduce the adsorption of proteins of different molecular weights and isoelectric points in serum. Based on these results, the ratio of alkyl thiols having EG and carboxylic acid terminals was optimized in order to prepare a new SPR sensor chip that can immobilize the sensing molecules while preventing non-specific adsorption. In this study, 4-aminophenyl boronic acid was fixed through amido bond formation on a mixed SAM sensor chip while aiming at the quantification of diol compounds. The SPR sensor using this sensing chip could determine GA, which is an example of a sugar-protein, in the concentration range of 7.5~20% (total amount of albumin).
Keywords : surface plasmon resonance; self assembled monolayer; non-specific; glycosylated albumin.
Kôki Nakamura1 and Eiko Nakamura2
1 Graduate School of Education, Yokohama National University, 79-2 Tokiwadai, Hodogaya-ku, Yokohama-shi, Kanagawa 240-8501(Received 26 December 2002, Accepted 24 February 2003)
The reduction of nitrate to nitrite by using cadmium coated with copper in a reductor column has been widely used on the determination of nitrate. The effects of the flow rate, pH and types of cadmium on the reduction have been investigated. However, the function of copper coated on cadmium has still not been elucidated. In this study, the reduction of nitrate by using cadmium without copper was investigated. Cadmium without copper reduced nitrate to nitrite the same way as cadmium coated with copper, if copper ion was added to a sample solution above 10 mg/l. It was presumed that the reduction of nitrate was affected by the copper ion in the sample solution, rather than copper coated on the cadmium. The effects of chloride ion and silicate on the reduction were smaller than that of cadmium coated with copper.
Keywords : reduction of nitrate; cadmium column.
Shogo Suzuki1, Yukiko Okada1 and Shoji Hirai1
1 Faculty of Engineering, Musashi Institute of Technology, 1-28-1, Tamazutsumi, Setagaya-ku, Tokyo 158-8557(Received 10 January 2003, Accepted 3 March 2003)
Multi-elements in JAC0021, JAC0022 and JAC0023 certified reference materials of high-purity aluminum prepared by the Japan Society for Analytical Chemistry (JSAC) were determined by instrumental neutron-activation analysis (INAA). Four or five aliquots of each sample (ca. 27~1018 mg) and comparative standards were irradiated for a short time (10 s) at a thermal neutron flux of 1.5×1012 n cm -2 s-1 (pneumatic transfer) and for a long time (6 h) at a thermal neutron flux of 3.7×1012 n cm-2 s-1 (central thimble) in the Rikkyo University Research Reactor (TRIGA Mark-II, 100 kW). The irradiated samples were measured by conventional γ-ray spectrometry using a coaxial Ge detector, and by anti-coincidence and coincidence γ-ray spectrometry with a coaxial Ge detector and a well-type NaI(Tl) detector. The concentrations of 21 elements in JAC0021, 20 elements in JAC0022 and 11 elements in JAC0023 were determined by these methods.
Keywords : determination of multi-elements by instrumental NAA; certified reference materials of high purity aluminum; g-ray spectrometry.
Mikio Kaihara1, Nobuyuki Takahashi1, Seikou Sato1, Yohko Higuchi1 and Satomi Yusa1
1 Department of Chemical Engineering, Ichinoseki National College of Technology, Hagisho, Ichinoseki-shi, Iwate 021-8511(Received 2 September 2002, Accepted 28 February 2003)
Water-quality data of rivers, for example, COD and BOD are important indices for environmental conservation. Whether we can distinguish between the sampling positions or the fiscal year, the sampling time of the water are depend on the way of characterizing the sampling positions or time of the water. We focused our attentions to one of the decision trees, the classification and the regressions trees (CART), because we should have clear splitting rules between the sampling positions or the sampling fiscal years. As a result of using CART, we found that classification between the upper, middle and lower area of Tama river could be completely done based on the conductivity and the chlorine ion. Furthermore, from the splitting rules between the water-quality data of fiscal year '97, '98 and '99, the important point concerning the purification of Tama river's water-quality, would be considerable reduction of the nitrogen-related chemical species (Total nitrogen, NH4, NO2, NO3). CART should be a useful method for finding the meanings of classifying or the splitting rules of the complicated analytical data or environment data, which have recently increased in number.
Keywords : quality of the river water; feature extraction; classification; classification and regression trees.
Yuji Anzai1 and Yoshifumi Akama1
1 Department of Chemistry, Faculty of Science and Engineering, Meisei University, Hodokubo 2-1-1, Hino-shi, Tokyo 191-8506(Received 16 January 2003, Accepted 3 March 2003)
An aqueous two-phase system, prepared by mixing a tetrabutylammonium bromide(TBAB) solution and Na2SO4, was proposed for the extraction of Au(III) and Pd(II) prior to atomic absorption spectrophotometric(AAS) determination. An aqueous two-phase system was obtained as follows: to a 1 ml sample solution containing Au(III) and Pd(II), 3.0 ml of 1.0 mol l-1 TBAB aqueous solution and 1.0 ml of a buffer solution (pH 4) were added and diluted with water to 6.0 ml. Then, 1.8 g of Na2SO4 was added to this solution and the mixture was shaken for about 1 min. After complete phase separation was performed, a 0.5 ml aliquot was taken from the upper phase and then diluted with 10 ml of water for AAS determinations of Au(III) and Pd(II). The Au(II) and Pd(II) were quantitatively extracted into the upper phase in the pH range from 1 to 6.5. The proposed method was applied for the determination of Au(III) and Pd(II) in a plating solution. The mean recoveries were 104 and 99% for Au(III) and Pd(II), respectively.
Keywords : aqueous two-phase extraction; tetrabutylammonium bromide(TBAB); Au(III); Pd(II).
Yoshinobu Yamamoto1, Yoko Yamabe-Mitarai1, Naoto Hirosaki1 and Hiroshi Harada1
1 National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba-shi, Ibaraki 305-0044(Received 8 January 2003, Accepted 10 March 2003)
It is well known that Ir is a chemically stable element that is difficult to dissolve, even in a strong acid. Furthermore, when transition metals are added to it, Ir becomes more difficult to dissolve in acid. To solve this problem, we tried to dissolve Ir-Nb, Ir-Zr, Ir-Nb-Zr, Ir-Nb-Pt, Ir-Nb-Pt-Al, and Ir-W alloys using a fusion method at 1073 K in sodium peroxide. This was successful, and the concentration of each element was analyzed with ICP-AES. The result was in good agreement with the nominal concentration. This shows that the fusion method in sodium peroxide and analysis with ICP-AES are suitable for Ir alloys.
Keywords : dissolving method; fusion method; Ir-alloy; sodium peroxide; ICP-AES.
Yuetsu Danzaki1 and Kazuaki Wagatsuma1
1 Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai-shi, Miyagi 980-8577(Received 2 September 2002, Accepted 11 February 2003)
Dissolution methods with acid solutions have generally been employed for the determination of Si in various samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). However, few reports on analytical procedures with alkaline solutions have been published. Si determination in a SiC sample could be successfully performed by using a dissolution technique with an alkaline solution. The SiC sample (40 mg) in a Pt crucible was fused with 2 g of Na2CO3. After the melt was dissolved with water in a Teflon beaker, the solution was finished with a polypropylene flask. The alkaline solution contained Ga added as an internal standard. The solution was diluted to 100 ml and then measured by ICP-OES. For obtaining a calibration curve, SiO2 powder was dissolved using the same procedure as that for the SiC sample. For a comparison, an acid solution was prepared by adding HCl-HNO3 to the solution after water-dissolving a SiC sample melted with Na2CO3. The acid sample solution contained Zn as an internal standard. A good agreement in the analytical result of Si was obtained between the alkaline sample solution and the acid sample solution.
Keywords : alkaline solution; Si in SiC; fusion with Na2CO3; ICP-OES.
Yuetsu Danzaki1 and Kazuaki Wagatsuma1
1 Institute for Materials Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai-shi, Miyagi 980-8577(Received 2 August 2002, Accepted 24 February 2003)
A new dissolution method of a Mn-Rh alloy including trace amounts of Al and Si has been developed for the precise analysis by inductively coupled plasma-optical emission spectrometry (ICP-OES). For the determination of Mn, Rh, Al and Si in Mn-Rh alloy samples (100 mg), the samples were dissolved with 20 ml of HBr-Br2, followed by the addition of 20 ml of HClO4 at room temperature; then, most of HBr was decomposed into Br2 with drops of H2O2. The resulting solution was concentrated to about 10 ml after the addition of 10 ml of HNO3, and MnO2 was decomposed with H2O2 after adding 10 ml of HCl (1+1) and 10 ml of H2O to obtain a clear solution. Si was determined by a gravimetric method. Moreover, after being measured by ICP-OES, the analytical results were estimated with the sequential correction method.
Keywords : Mn-Rh alloy; dissolution with HBr-Br2; ICP-OES.
Hanako Ishikawa1, Kumiko Okumura1, Naomi Naito1, Takeshi Harada1, Yoshiyasu Yamauchi1, Kyoko Yamasaki1, Mariko Murayama1 and Toshihide Ihara2
1 National Institute of Technology and Evaluation, 2-49-10, Nishihara, Shibuya-ku, Tokyo 151-0066(Received 17 October 2002, Accepted 26 February 2003)
As the establishment of environmental quality standards is being promoted, the reliability of environmental analysis is one of the most important issues. The environmental problems caused by toxic organic substances in particular have become serious in recent years; therefore, there is much demand for standard gases and solutions for these analyses. Because the exact concentrations of these calibration standards are of great significance to obtain reliable measurement values, the concentrations and uncertainties of these calibration standards are required. Volatile organic compounds (VOCs), such as trichloroethylene and benzene, are part of the emission and environmental quality standards; therefore, the calibration standards of these VOCs are demanded for environmental analysis. To ensure the reliability of these calibration standards, purity evaluations of these VOCs are essential. In many cases the purity of VOC is evaluated by the relative peak area percentage of the main component only by GC-FID analysis for convenience and versatility. However, because of the various kinds of organic compounds, including stabilizers, in the VOC, the sensitivities of the compounds against the main component will be different by GC-FID. Although the identification and measurement of these impurities will offer valuable information for calibration standards and for preparing multi-component standard gases and solutions, these impurities are rarely analyzed. For these reasons, purity evaluations and information on impurities in VOCs have great meaning for preparing standard gases and solutions. The purpose of this study is to establish a purity evaluation method for VOCs by GC-FID to prepare accurate standard gases and solutions. We selected seventeen frequently used VOCs, and attempted to determine each impurity and to estimate their uncertainties. In our work, the internal standard is added directly to the target VOC for a quantitative analysis, rather than using another solvent for dilution. The relative sensitivities of the impurities against the internal standard are measured in advance. As a result, we can analyze trace impurities in VOC precisely, and calculate the purity and uncertainty by the subtraction method. The VOC calibration standards for environmental analysis can be easily provided by the method proposed in this study.
Keywords : purity evaluation; standard gases and standard solutions; volatile organic compounds; GC-FID; uncertainty.
Go to the page of "Bunseki
Kagaku"
Go to the top page of JSAC©2003 The Japan Society for Analytical Chemistry
All rights reserved.
26-2, Nishigotanda 1-chome, Shinagawa-ku, Tokyo 141-0031, JAPAN