Vol. 54 No. 10
October, 2005
Kumiko Takeda1 and Yoshiko Arikawa1
1 Division of Material and Biological Function Sciences, Graduate School of Science, Japan Women's University, 2-8-1, Mejirodai, Bunkyo-ku, Tokyo 112-8681(Received 27 April 2005, Accepted 30 July 2005)
The decomposition of a sample by the high pressure oxygen combustion method and the preconcentration process using chelating resin (Chelex 100) were studied for the determination of rare earth elements (REEs) in petroleum by ICP-MS. In the decomposition procedure, a 1 g of petroleum sample was burnt in 3 MPa of Oxygen in a stainless vessel with 5 ml of 5%HNO3-1%H2O2 absorbing solution. In the preconcentration process, the pH of absorbing solution after the combustion was adjusted at 4 with an ammonia solution and then stirred after the addition of 1 g of chelating resin (Chelex 100). The resin was collected on a glass filter. REEs ions adsorbed on the resin were eluted with 2 mol/l HNO3. The solution was transferred to 10 ml volumetric flask and REEs were measured by ICP-MS with internal standard elements, such as Be for Sc, In for Y~Sm and Re for Eu~Lu. The observed concentration of REEs were corrected by subtracting the spectral interferences. REEs in some real petroleum samples were determined.
Keywords : ICP-MS; high pressure oxygen combustion method; rare earth elements; petroleum; chelating concentration.
Ai Shimada1, Miho Tanaka1, Shin Kumakura1 and Kazuya Takahashi2
1 Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo 108-8477(Received 17 April 2005, Accepted 17 August 2005)
Manganese nodules, which are mainly composed of manganese and iron oxide, show the structure of annual rings. Chemical compositions vary widely, such as the concentrations of Co, Ni and Cu, and the relative ratio of Mn/Fe. It may be possible to analyze the old environmental changes from the chemical composition. In this study, characterization of the chemical composition of manganese nodules was performed to find the factors concerning the effect of a changing of environment. In the sample, a characteristic layer was found in a raster image of X-rays by SEM-EDX. In this layer, the abundances of iron and sulfur were high, but manganese was low. In this particular structure, pyrite should be considered to occur as very small particles. Further, manganese nodules were examined along the structure of annual rings in more detail for chemical composition, which confirmed the result of SEM-EDX. The main elements were analyzed by an inductively coupled plasma atomic emission spectrometer (ICP-AES), and trace elements were analyzed by an inductively coupled plasma mass spectrometer (ICP-MS). As a result, the distribution of the elements changed to 1/3 from 1/2 and 3/4 from the center. The distribution of the elements changed one after another at the former. The latter agreed with the section at which there was sulfur when analyzed by SEM-EDX. The distribution of the elements suddenly changed at the same time at the latter. Therefore, we can guess that the different changes of the environment occurred twice.
Keywords : manganese nodule; structure of annual rings; element distribution; environmental changes.
Takashi Suekane1, Mitsuko Oshima1 and Shoji Motomizu1
1 Department of Chemistry, Faculty of Science, Okayama University, 3-1-1, Tsuishimanaka, Okayama-shi, Okayama 700-8530(Received 15 April 2005, Accepted 22 August 2005)
Ammonia in the atmosphere can be determined by an improved indophenol method with 1-naphthol. Ammonia dissolved in water reacts with sodium hypochlorite in the presence of sodium hydroxide and 1-naphthol to form an indophenol blue dye, which can be measured at 720 nm (maximum absorbance). Since ammonia in the atmosphere can be absorbed in purified water almost completely, a calibration graph using standard aqueous ammonium chloride solutions can be used. The calibration graph showed a good linearity (y=0.37×105x+0.027, R2=0.9992) and the detection limit was 0.9×10-6 M. For practical samples, the air was collected into a 50 ml plastic syringe with an air-tight cap containing 3.0 ml of purified water as the absorbing solution, followed by shaking it by hand. The method was successfully applied to the determination of ammonia in indoor and outdoor air samples.
Keywords : ammonia; 1-naphthol; air sample; spectrophotometry.
Taihei Muramoto1, Shota Shigihara1, Tokuo Shimizu1 and Nobuo Uehara2
1 Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, 7-1-2, Yoto, Utsunomiya-shi, Tochigi 321-8585(Received 14 April 2005, Accepted 27 July 2005)
A novel method for the determination of trace amounts of selenium in iron and steel has been demonstrated by a HPLC using 2,3-diaminonaphthalene (DAN) as a derivatizing reagent. Certified reference materials of iron and steel were used to prepare digestive samples by decomposition with hydrochloric acid and nitric acid followed by phosphoric acid huming. Selenium(IV) in the digestive samples was extracted with DAN into cyclohexane. The 100 µl of cyclohexane phase was injected into the HPLC with fluorometric detection. Cyclohexane - tetrahydrofuran (90 : 10 v/v) mixture was used as an eluent and effluent was monitored at 380 nm and 530 nm as excitation and emission wavelength, respectively. A linear calibration was observed in the selenium concentration range from zero to 6.0 ng/ml. The detection limit (3s) of Se(IV) was 0.12 ng/ml, which corresponded to 0.12 ppm in iron and steel samples. The good agreement between determined values with both the proposed method and GD-MS indicates that the proposed method is of great promise for the determination of selenium present in iron and steel.
Keywords : 2,3-diaminonaphthalene; selenium; HPLC; iron and steel; determination.
Hiroo Isagai1 and Hayao Sakamoto1
1 Faculty of Science, Kagoshima University, 1-21-35, Korimoto, Kagoshima-shi, Kagoshima 890-0065(Received 15 April 2005, Accepted 10 August 2005)
The adsorption of copper(II) to Shirasu, a pyroclastic flow deposit, was examined by a batch-and-column method. The effect of the grain size was investigated in the range <74~250 µm. The amount of copper(II) adsorbed on Shirasu increased with decrease of the grain size. A highest value was observed for grain size of <74 µm. This tendency was remarkably observed at a higher copper(II) concentration. The effect of the pH was investigated at pH 1.0, 3.0 and 5.0. At pH 1.0, no adsorption of copper(II) on Shirasu was observed. As the pH increased, the adsorbed amount of copper also increased. The adsorption data for copper(II) was also analysed using logarithmic form of the Freundlich isotherm, logW=logK+1/nlogCe. When logW is plotted against logCe, a straight line with a slope of 1/n and an intercept of logK is obtained. This reflects satisfaction of the Freundlich isotherm model for the adsorption of copper(II). The increase in the adsorption amount of copper(II) with a decrease of the grain size can be explained by the increase in the K value. The increase of the pH can be explained by the increase in both of the K and 1/n values.
Keywords : adsorption; copper(II); Freundlich isotherm; Shirasu.
Toru Fukuda1, Shinichi Ishida2, Tatsuro Nakagama1, Shigeyuki Koike2 and Katsumi Uchiyama1
1 Faculty of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1, Minamiosawa, Hachioji-shi, Tokyo 192-0397(Received 14 April 2005, Accepted 18 August 2005)
It was found that the UV-absorbance of sugar alcohols was enhanced by a reaction with titanium alkoxide {titanium tetraisopropoxide (TTIP)}. 29- and 146-fold increases of the absorbance of sorbitol and xylitol at 250 nm by reactions with TTIP were found, respectively. Good linear relationships (r≥0.9794, n=5) between the absorbance at 250 nm and the concentration of these sugar alcohols were obtained. When a 4.9 mM sorbitol aqueous solution was used as the sample, the repeatability, including the sample-preparation step, became 6.0% (n=3) as the relative standard deviation.
Keywords : sugar alcohol; titanium alkoxide; spectrophotometric determination.
Naho Yamasaki1, Kazuhiko Matsuoka1, Kazuhito Nagayama2, Takashi Hata2, Hitoshi Matsuki4, Hiromu Satake3 and Shoji Kaneshina4
1 Advanced Course in Materials Science and Engineering, Kochi National College of Technology, 200-1, Monobe-otsu, Nankoku-shi, Kochi 783-8508(Received 15 April 2005, Accepted 7 August 2005)
Some aromatic amine local anesthetics are a kind of amphiphilic ion. Binding of local anesthetics, dibucaine (DC), bupivacaine (BC), and lidocaine (LC) to a dipalmitoylphosphatidylcholine (DPPC) bilayer membrane was studied by potentiometry with ion-selective electrodes sensitive to DC, BC and LC cations, respectively. The DPPC membrane-buffer partition coefficient was directly determined as a function of the anesthetic concentration and the temperature. The DPPC bilayer underwent a thermotropic pretransition from the lamellar gel phase to the ripple gel phase as well as a main transition from the ripple gel phase to the liquid crystal phase. The partition coefficients of anesthetics at pH 5.5 varied with the temperature, namely the bilayer phases. Potentiometry using an ion-selective electrode sensitive to amphiphilic ions is effective for the detection of a bilayer phase transition through partition coefficients.
Keywords : ion sensor; local anesthetic; lipid bilayer membrane; phase transition; partition coefficient.
Masataka Onozato1, Kuniaki Kawata1, Chie Sugisaki1, Takashi Asada1 and Kikuo Oikawa1
1 Faculty of Applied Life Sciences, Niigata University of Pharmacy and Applied Life Sciences, 265-1, Higashijima, Niigata-shi, Niigata 956-8603(Received 18 April 2005, Accepted 26 August 2005)
Sample-preparation methods were examined to determine nitrate in vegetables. Filtrated treatments before storage made the NO3- lifetime of sample solutions longer. Furthermore, the extraction effects of nitrate ion from homogenized extraction were equal to those from ultrasonic extraction. When nitrate ion was added to the sample solution from a Chinese cabbage, a kidney bean, and a sweet potato, the reproducibility and the recovery of nitrate ion were satisfactory for all vegetables.
Keywords : ion chromatography; nitrate ion; sample preparation; vegetable.
Tohru Yamagaki1
1 Department of Chemistry, School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033(Received 4 April 2005, Accepted 3 July 2005)
Structure analyses of oligosaccharides are performed by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and electrospray ionization mass spectrometry (ESI-MS). The structural isomers of oligosaccharides are distinguished by an analysis of the relative abundance of the product ions. These isomers are classified into three categories: branch isomers, linkage isomers, and isomeric mono-saccharides. We can analyze these isomers systematically by the analytical method of the relative abundance of the product ions.
Keywords : MALDI-TOF MS; fragmentation; isomer; oligosaccharide..
Nozomi Tsuzaki1, Mayuko Osaki2, Bunbunoshin Tomiyasu3, Masanori Owari2,3 and Yoshimasa Nihei1
1 Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510(Received 1 February 2005, Accepted 27 June 2005)
It has recently been reported that the PGE (platinum group element) containing particles that originate from automobile catalysts are emitted into the atmosphere, and have a certain influence on ecological and human health risks. In the present work, an analytical method using EPMA (electron probe micro-analysis) was developed in order to find a small number of PGE-containing particles from a very large number of atmospheric particles. First, by comparing the WDS (wavelength dispersive spectrometer) and EDS (energy dispersive spectrometer) measurement systems in EPMA, the WDS measurement was proved to be advantageous for the analysis of such particles. Next, the optimal condition of WDS mapping was determined based on a theoretical model and standard sample measurements. From the results of measurements on a model sample under the conditions mentioned above, several PGE-containing particles were identified in real samples. As a result, the analytical method proposed in this paper was proved to be very useful concerning airborne particles by using EPMA.
Keywords : electron probe microanalysis; platinum group element; atmospheric particle; element mapping; rare particle.
Fumihiro Kodera1, Minoru Umeda2 and Akifumi Yamada2
1 Environmental Science Research Niigata, Advanced Ttechnology Center, 333-1, Minamiyachi, Niigata-shi, Niigata 953-0135(Received 22 April 2005, Accepted 28 June 2005)
We developed a new analysis method of hypochlorite using a reduction wave observed at about 600 mV vs. Ag/AgCl, after the potential sweep direction was switched from anodic to cathodic. The measurement was performed using mirror-polished pure platinum as a working disk electrode. For the reduction wave observed at a switching potential of 1200 mV vs. Ag/AgCl, the cathodic peak current and the concentration showed a good linear relationship at a concentration range of 0.2~6.0 mg dm-3. The relative standard deviation (n=3) of the reduction wave gave a good result of RSD<0.02. This electrode reaction was investigated by varing the pH value, the switching potential, and the sweep rate. As a result, it is considered that the cathodic current can be attributed to the reduction of HClO, which is formed by shifting the pH to the acidic direction based on water electrolysis during anodic polarization.
Keywords : hypochlorite; anodic polarization; electroreduction; platinum.
(Received 4 October 2004, Accepted 22 June 2005)
Microwaves of 2.45 GHz frequency from a commercial microwave oven irradiated a glycerol solution of AgNO3. By the irradiation of microwaves, the temperature of the reaction solution increased up to above the boiling point of glycerin. After ceasing irradiation, the color of the solution turned to yellow, and fine silver particles were formed. From an XRD analysis, it was found that the resulting fine particles had crystal - like structures. SEM observations showed the generation of large (~1 mm) particles. From laser scattering measurements, on the other hand, Ag fine particles with a mean size of ~100 nm were also found in the supernatant solution after a centrifugal separation. The formation of ~1 mm crystal - like particles may result from the collisions of fine particles produced during the microwave irradiation process. The results imply that glycerin reduces Ag+ to Ag effectively.
Keywords : microwave; glycerol; AgNO3; microwave heating; Ag particle.
Yoshio Iida1, Shozo Asada1, Hiroyuki Igaki1, Yo-ichi Ishibashi1, Ko-ichi Tanaka1, Satoshi Tsuruta1, Kazutoshi Kakita1, Akihiro Ono1 and Mamoru Sakata1
1 The Japan Society for Analytical Chemistry, 1-26-2, Nishigotanda, Shinagawa-ku, Tokyo 141-0031(Received 28 April 2005, Accepted 21 June 2005)
The Japan Society for Analytical Chemistry has developed a new certified reference material (CRM) for analyses of dioxins (polychlorodibenzo-p-dioxins and polychlorodibenzofurans) and coplanar polychlorobiphenyls. A project team has been organized to prepare a homogeneous fly-ash and to certify the concentrations of dioxins and PCBs. An interlaboratory comparison test was performed with the participation of 18 laboratories. In a statistical analysis of the data sent from laboratories, z-scores in a robust method were applied to reject outliers and were followed by the usual statistical procedure. The presented CRM is now contributing usefully to the quality assurance and quality control of dioxins analysis.
Keywords : dioxins; PCBs; fly-ash; interlaboratory comparison test; certified reference material.
(Received 10 May 2005, Accepted 1 July 2005)
This study examined a sample-preparation procedure in the glow-discharge mass analysis of yttria-stabilized zirconia (YSZ). We investigated a procedure for mixing it with high-purity gallium to guarantee the electrical conductivity. Several chips of single-crystal specimens were placed in the center of a homemade PTFE mold, embedded with 6 g of molten gallium (Ga), and then cooled and solidified. Three samples were subjected to an evaluation of the reproducibility in repetitive IBR measurements. Although the IBR of Ga to Zr varied with a difference in the respective occupation rate in the discharge area, the variation was less than 2% in RSD. Furthermore, the relative errors among three samples were less than 2% in Y and Hf, the main components, and less than 10% in trace impurities. Therefore, this method was proved to be applicable as a sample-preparation procedure. Moreover, we studied spectrum interference caused by the matrix and discharge gas, conducted a detailed analysis of composite molecular ions, and determined the optimal isotope for the measurement.
Keywords : sample-preparation method; yttria-stabilized zirconia; glow-discharge mass spectrometry.
Hiroyuki Ida
Forensic Science Laboratory, Kyoto Prefectural Police Headquarters, Kamanzadori Shimodachiuri, Kamigyo-ku, Kyoto-shi, Kyoto 602-8550
(Awarded by Kyoto University dated March 23, 2005)
X-ray fluorescence (XRF) analysis with two portable instruments, a pyroelectric X-ray generator and a hand-held spectrometer, has been studied. The pyroelectric X-ray generator is a novel X-ray source that utilizes a charging phenomenon on a pyroelectric crystal to generate X-rays. This X-ray source has such characteristics as dry battery drive and periodically changing low X-ray output. The latter seems to be a disadvantage for XRF analysis. However, in the present study, the capability for elemental analysis at % level and the identification of many samples based on the spectral difference was demonstrated. Moreover, the capability for quantitative analysis at ppm level with a chelate extraction method or an ion-exchange method was proved. High sensitization of the analysis was achieved by using a disk-shaped secondary target with a hole in its center. Large solid angle X-rays emitted from this generator were effectively put to use by the straight-line arrangement of the X-ray generator, sample support, secondary target, and detector. With regard to the hand-held spectrometer, shielded objects were analyzed, and their composition could be estimated with an error of less than 30% by using the attenuation coefficient. This study presented new applications of portable spectrometers.
(Received June 17, 2005)
Keywords : X-ray fluorescence; portable instrument; pyroelectric X-ray generator; hand-held spectrometer; identification.
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