Vol. 50 No. 12
December, 2001
Kiyokatsu Jinno, Yoshihiro Saito and Motohiro Imaizumi*
*School of Materials Science, Toyohashi University of Technology, 1-1, Hibariga-oka, Tempaku-cho, Toyohashi-shi, Aichi 441-8580
(Received 25 July 2001, Accepted 3 September 2001)The miniaturization of analytical systems is the most important issue in recent analytical chemistry, since it realizes high performance, rapid analysis with low-cost operation and environmental compatibility. In a typical analytical system, two major processes exist, such as a procedure for sample preparation and another procedure for actual analysis. In the former part, extraction and preconcentration are the major purposes for preparing analytical samples before analysis. As a conventional method, liquid-liquid extraction (LLE) or solid-phase extraction (SPE) are popular. In the latter part, separating components in an analytical sample and then identifying and quantifying each isolated component should be performed by using chromatography and spectroscopy as the hyphenated system. Liquid chromatography (LC) coupled with photodiode array UV/Vis detection and/or mass spectrometric detection (MS) are very popular. At the present time, although many attempts have been made to realize a miniaturized system, we are still far from realizing the most ideal and useful one. In our previous investigations, a miniaturized analytical system for practical applications using a novel “fiber-in-tube” configuration was developed and applied to the sample-preparation process as an SPE medium. Fiber-packed columns have been studied in capillary separations, such as microcolumn LC, capillary electrochromatography (CEC) and gas chromatography (GC). In this article, recent results concerning the miniaturization of these analytical systems are reviewed while mainly focusing on a novel usage of synthetic polymeric fibrous materials.
Keywords : fibrous polymer; fiber-in-tube solid-phase extraction; sample preparation; stationary phase; chromatography.
Shin-ichi Wakabayashi*
*Shinko Electric Industries Co,. Ltd., 1457-1, Wakaho, Kawada, Nagano 381-0103
(Received 13 July 2001, Accepted 30 August 2001)Semiconductor packages are requiring a wide range of functions covering from simple chip mount, protection from ambient circumstances and mechanical damages as well as additional functional requirements, such as thermal dissipation, stable power supply and integrity of high-frequency signals. Semiconductor Jisso technology (packaging and interconnect technology) should cover packaging, substrate and module manufacturing technologies; therefore, the material, process and design should be properly optimized and controlled. To satisfy these requirements, many analytical methods from classical gravimetric and volumetric analysis to ICP, GC-MS and EPMA, ESCA, AES have been applied. In this paper, the analytical data obtained on gold and silver plating processes, and the assembly processes such as wire bond, molding and soldering etc., are described in details. The importance of the analysis “to see” what, where, how much and how to be (chemically and geometrically) is stressed.
Keywords : semiconductor package; gold and sliver plating; EPMA, ESCA, FIB-SIM analysis for package; flip chip attach and void detection in solder bumps; advanced build up substrate; via fill by copper plating.
Takuya Kondo and Takashi Kuzuya*
*Toyota Motor Corporation, 1,Toyota-Cho, Toyota-shi, Aichi 471-8572
(Received a July 2001)The history of analysis technology in Toyota is old. For example, Toyota prepared a chemistry laboratory during 1934. At that time, the analytical role had a main classification to judge steel materials. Analysis became an indispensable technology in the development of mass-production technology, corresponding to a subsequent rise in demand for automobiles. Also the development of exhaust-gas measuring and energy-saving technology occurred because of air pollution and oil crise. Examples are analysis technology in the development of NOx storage reduction catalyst, a highly efficient Nickel-metal hydride (Ni-MH) battery, and a hydrogen-absorbing alloy. Presently (during the 21st century), the automotive industry is facing such subject areas as energy, the environment, safety, and information technology (IT). In order to address these issues, the expectations of analysis increase. We are now paying attention to, and expect breakthroughs in the following techniques: (1)An in-situ technique where the material action can be determined under the used condition. (2)The fusion of analysis technology and computer-aided engineering (CAE), which enables a related interpretation with the molecular/atomic structure of the material, and an analytical output. (3)Analysis technology for catching the action of hydrogen and water, which are considered to be difficult to analyze directly.
Keywords : automobile; catalyst; battery; hydrogen absorbing alloy; analysis of material.
Ken Matsumoto and Toshihiro Koura*
*Department of Chemistry, Faculty of Science, Kanazawa University, Kakuma-machi, Kanazawa-shi, Ishikawa 920-1192
(Received 12 July 2001, Accepted 31 July 2001)A simple and rapid method for the decomposition of refractory barium sulfate has been proposed. Barium samples(BaSO4, ore) were decomposed by fusion with ammonium hydrogen sulfate, which was found to be a suitable powerful flux for dissolving various refractory sulfates. An accurately weighed sample(ca. 10 mg) was placed in a dry Pyrex test tube (18 mm o.d., 200 mm length). Ammonium hydrogen sulfate(ca. 2 g) was added to the tube and mixed with the sample by agitating the tube. The bottom of the test tube was gently heated along with a swirling motion over a small gas flame of a Bunsen burner with a fish-tail at a temperature of ca.550~600°C. Heating was continued until the melt changed into a colorless, clean and translucent form. Barium sulfate was dissolved by heating for about 5 min. After cooling, the solidified melt was dissolved in 30 ml of a 0.05 M EDTA-ammoniacal solution (3.5 M in ammonia). Finally, the concentration of the barium in the resulting solution was determined by ICP-AES or flame photometry. The proposed method was successfully applied to various sulfates and ores. The barium and other metals in the samples were determined and the analytical results of barium were in good agreement with the values obtained by fusion with alkali metal carbonate.
Keywords : refractory sulfate; decomposition of barium sulfate; fusion with ammonium hydrogen sulfate; determination of barium in sulfate and ore.
Junko Terasawa, Kotaro Mitsuya*, Akira Ishii** and Takao Tsuda*
*Department of Applied Chemistry, Nagoya Institute of Technology, Gokiso, Showa-ku, Nagoya 466-8555
**Department of Legal Medicine and Bioethics, Post Graduate School of Medicine Nagoya University, 65, Tsuruma, Showa-ku, Nagoya 466-8550
Cations in human insensible perspiration were analyzed by capillary zone electrophoresis. A simple sampling method from the skin surface of the forefinger of a hand was devised. After washing the forefinger with tap water and then distilled water for 10 s, 40 µl of a 10% ethanol aqueous solution kept in a small vial (0.6 ml) was allowed to contact the treated forefinger for 3 minutes. The sweat sample was then analyzed by capillary zone electrophoresis. A mixture of 5.0 mmol l-1 copper(II) acetate, 10 mmol l-1 ethylendiamine and 1.0 mmol l-1 18-crown-6-ether at pH 6.5 was selected as the optimum medium for capillary zone electrophoresis. Six cations {Rb+(I.S.), K+, NH4+, Na+, Ca2+ and Mg2+} were completely separated in less than 3 min, and detected with indirect UV detection at 230 nm. Sweat samples were collected from seven volunteers. They were healthy males (n=4) and females (n=3), aged 21~25 years. The mean values of the cation concentrations were K+=39.9 mM, Na+=54.0 mM, Ca2+=5.49 mM, Mg2+=1.67 mM, NH4+=5.13 mM. It shoud be noted that the concentration of K+ in secreted sweat is much higher than that in serum.
Keywords : capillary zone electrophoresis; cation; sweat; potassium ion; sampling.
Jinghua Zhang, Naoki Nishimura, Mitsuru Abo, Akira Okubo* and Sunao Yamazaki**
*Department of Applied Biological Chemistry, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-8657
**Faculty of Environmental Studies, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521
A capillary electrophoresis method using a low-pH electrolyte solution and UV detector for the determination of 3-dimethylsulfoniopropionate (DMSP) in tissue extracts of marine algae is described. Adjusting the pH of the electrolyte to an acidic condition of around 3 resulted in a high separation between DMSP and other related sulfur compounds. Two methods were investigated. Water extracts of algal samples were directly applied to capillary electrophoresis and detected at 190 nm (direct method). In order to obtain high sensitivity, esterification of DMSP was carried out at 70°C for 40 min to keep the degradation of DMSP at less than 5%. The reaction mixture was determined at 254 nm (esterification method). A good linearity was shown in the concentration range from 0.50~20.0 mM with a detection limit of 0.25 mM (S/N=3) for the direct method, and 0.02~5.0 mM with a 0.005 mM detection limit (S/N=3) for the esterification method. For both methods, the repeatability (n=3) of the migration time and the peak area were less than 0.7% and less than 3% as RSD, respectively. In addition, nearly similar values were obtained when both methods were applied to algal samples collected from Tokyo Bay, indicating the suitability of the methods for DMSP determination.
Keywords : p-bromophenacyl ester; capillary electrophoresis; DMS; DMSP; marine algae.
Toyohide Takeuchi and Lee Wah Lim*
*Department of Chemistry, Faculty of Engineering, Gifu University, 1-1, Yanagido, Gifu 501-1193
(Received 11 July 2001, Accepted 14 Septemer 2001)Stepwise-gradient elution was carried out with a gas-pressure-driven flow system. The system was assembled from a gas cylinder, a 6-way selection valve, an injection valve(or a sample-enrichment system), a separation column, a UV detector and a syringe pump. Eluents with different compositions were supplied by pressure applied from an argon gas cylinder; switching the 6-way selection valve changed the eluent composition. The syringe pump located downstream of the detector regulated the flow rate of the eluent. The relative standard deviation of the retention time was 0.4-0.6% for isocratic elution as well as for two-step gradient elution. The system was applied to the separation of phthalates and alkylbenzenes.
Keywords : gas-pressure-driven flow; stepwise-gradient elution; postcolumn-controlled flow system; microcolumn liquid chromatography.
Kazumi Inagaki, Akiko Takatsu, Atsuko Nakama, Akira Uchiumi and Kensaku Okamoto*
*National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 3-10, 1-1-1, Umezono, Tsukuba-shi, Ibaraki 305-8563
(Received 17 July 2001, Accepted 5 September 2001)An isotope-dilution mass-spectrometric method was applied to the determination of Cd and Pb in sediment. The co-precipitate separation method using hydroxides of Al and Fe as a carrier precipitant was examined to overcome the spectral interference of ZrO+ and Sn+ on Cd isotopes. The amount of 204Hg that interferes with the 204Pb measurement was estimated from a measurement of 202Hg. The measured 111Cd/112Cd of digested solutions of pond-sediment reference material (NIES No.2) and a CCQM sample after co-precipitation were almost identical to that in a Cd standard solution. The interference of 204Hg on 204Pb was satisfactorily corrected by a mathematical correction method. The analytical results for Cd and Pb in NIES No.2 are 0.819±0.011 µg g-1 (value±expanded uncertainty) and 103.81±0.76 µg g-1, respectively, and were in good agreement with their certified vales (Cd: 0.82±0.06 µg g-1, Pb: 105±6 µg g-1). The present method was also applied to a CCQM key comparison (CCQM-K13, Cd and Pb in sediment); good analytical results for both Cd and Pb were obtained.
Keywords : isotope-dilution ICP-MS; sediment; key-comparison (CCQM-K13); cadmium; lead; uncertainty.
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
A preliminary experiment for the preparation and evaluation of industrial waste incineration fly ash reference samples was examined. About 2 kg of industrial waste incineration fly ash was sieved with 4 different mesh sizes of sieves. The fraction sieved through a normal sieve of 133 %r%Um(135 mesh) was used to prepare reference samples after blending with a rocking mixer. Finally, the fly ash sample was packed in 145 glass bottles (10 g each) as reference samples. In order to check their homogeneity, twenty samples taken from 4 bottles (5 samples each) were analyzed. The between-bottle variations were evaluated by analysis of variance (ANOVA) for major elements. The between-bottle variations for Na, Zn and P contents were within the allowed variance, while other elements(Mg, Si, Ti, Ca, Al, Fe) provided slightly large variances, because those particles from different origins might be contained in the fly ash reference sample. Furthermore, a multielement determination of the major-to-ultratrace elements in an industrial waste incineration fly ash reference sample was carried out using ICP-AES and ICP-MS after alkali fusion using LiBO2. About 50 elements over the concentration range from mg g-1 to sub-µg g-1 were determined with fairly good precision. The industrial waste incineration fly ash reference sample contained significantly large amounts of chalcophile elements, which may indicate large amounts of use in industrial activities.
Keywords : industrial waste incineration fly ash; reference sample; homogeneity test; multielement analysis; plasma spectrometry.
Aritaka Matsunani, Fumie Akimoto, Ippei Kodama*, Yuichi Kamata**, Kuniyuki Kitagawa, Norio Arai*, Takuya Higuchi, Akinori Ito and Hiroki Haraguchi***
*Research Center for Advanced Energy Conberstion, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603
**Department of Physics, Graduate of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602
***Department of Applied Chemistry, Graduate School of Engineering, Nagoya Unibersity, Furo-cho, Chikusa-ku, Nagoya 464-8603
Endeavors to reduce greenhouse gases have been made in all of the world. Nitrous oxide, N2O has not widely been recognized for a greenhouse gas. Some investigations to search the emission sources of N2O and to establish the decomposition method of N2O have just been started. We have continuously monitored atmospheric concentration of N2O at our center of Nagoya University. By the timing correlation analysis of the monitoring data of N2O and those of other greenhouse gases, we tried to find their correlations and identify the emission sources of N2O. In this paper, the results of our study on auto correlations and cross correlations of N2O with other greenhouse gases, CO2 and CH4, and climate parameters are reported. As a result, it becomes clear that though N2O concentration changes slowly and an amplitude of the change is very small in comparison with CH4 and CO2, all of them shows the same periodicity at 1 day. Moreover, an increase in N2O concentration of summer and a dependence of N2O concentration on wind direction were found.
Keywords : nitrous oxide; continuous monitoring; atmospheric concentration; auto correlation; cross correlation.
Tatsuhiko Tanaka, Keisuke Shitan* and Hiroyuki Kondo**
*Faculty of Engineering, Tokyo University of Science, 1-3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601
**Advanced Materials & Technology Research Laboratories, Nippon Steel Corp., 20-1, Shintomi, Futtu-shi, Chiba 293-8511
A rapid and highly sensitive system has been developed for the determination of copper in steel by differential pulse anodic stripping voltammetry coupled with electrolytic dissolution of a solid sample. Disk-shaped steel samples were anodically dissolved at a constant current of 5 A (current density of ca. 1.6 A cm-2) for 30 s in 5 cm3 of 6 mol dm-3 hydrochloric acid with vigorous stirring, with 100s current efficiency. After the addition of 10 cm3 of a 2 mol dm-3 sodium hydroxide solution, copper(II) in the resulting solution was electrodeposited on a glassy carbon electrode at -0.8 V vs. Ag/AgCl for 60 s without any removal of the iron matrix; the deposit was then anodically stripped at a scan rate of 80 mV s-1 to 0 V vs. Ag/AgCl in the same electrolysis cell. All measurement sequences were automatically controlled. The determination of 0.001 to 0.051 mass% of copper in steel was achieved with relative standard deviations below 5s within 120 s. The proposed analytical system is applicable not only to the rapid determination of 0.0003 to 0.26 mass% of copper in steel with electrodissolution times of 3 to 50 s, but to the multi-element determination of metallic elements in steel, and is suitable for controlling the steel making process and the product quality at production sites.
Keywords : copper; steel; rapid analytical system; electrolytic dissolution; differential pulse anodic stripping voltammetry.
Yoshinori Uwamino, Hisashi Morikawa, Akira Tsuge, Kiyoshi Nakane* and Toshio Ishizuka**
*National Institute of Advanced Industrial Science and Technology(AIST), Ceramics Research Institute, 2266-98, Shimosidami-Anagahora, Moriyama-ku, Nagoya 463-8560
**Faculty of Science, Niigata University, 8050, Ikarashi 2-no machi, Niigata 950-2181
A high-temperature pressure acid decomposition was examined to shorten the time required to decompose alumina for the analysis of impurities with ICP-AES. The sample and sulfuric acid were heated below 290°C in a PTFE-15% graphite vessel. In the case of raw material powder samples, the decomposition time was not always shortened by applying high-temperature to the decomposition. The times required to decompose several products of sintered samples at 290°C were reduced to 1/2~1/7 of those at 230 °C without any significant increase in the contamination, except for Si. The analytical results of Si in the ICP-AES for solutions obtained with 290°C decomposition were higher than those obtained with 230°C decomposition. For the most part, the excess Si was attributed to Si from the quartz ICP torch being attacked by a higher concentration of fluoride ion produced from the PTFE vessels under high-temperature conditions.
Keywords : determination of impurities in sintered alumina; high-temperature pressure acid decomposition; PTFE-15% graphite vessel; ICP-AES; Si contamination; fluoride ion production.
Kazuya Uesawa, Nobuo Uehara*, Kiyotaka Ito** and Tokuo Shimizu*
*Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, 7-1-2, Yoto, Utsunomiya-shi, Tochigi 321-8585
**Research & Development Lab., Daido Steel Co. Ltd., 2-30, Daido-cho, Minami-ku, Nagoya 457-8545
The direct determination of trace amounts of boron in iron and steel by ion-pair reversed-phase HPLC with a laboratory-packed ODS column was studied. The laboratory-packed ODS column was prepared by packing a slurry in which ODS silica gel (particle size, 5 µm) was suspended. The iron and steel were decomposed by a mixture of hydrochloric acid and nitric acid. The decomposition solution was fumed with sulfuric acid and phosphoric acid, and then evaporated to dryness. The residue was dissolved in an appropriate volume of dilute hydrochloric acid. After an aliquot of this solution was taken into 25 cm3 of a polypropylene volumetric flask, 2.5 cm3 of 7.5×10-3 mol dm-3 1,8-dihydroxy-3,6-naphtalenedisulfonic acid (chromotropic acid), 2.5 cm3 of 0.275 mol dm-3 EDTA, and 2.5 cm3 of 1.0 mol dm-3 acetate buffer (pH 8.0) containing 0.5 mol dm-3 of octyltrimethylammonium bromide were added. The solution was then diluted to 25 cm3 with water. After the solution was allowed to stand for over 10 min, a 200 mm3 portion was injected into the liquid chromatograph. The eluent used was aqueous-methanol (45:55 w/w) containing 5.0×10-2 mol kg-1 of octyltrimethylammonium bromide and 5.0×10-3 mol kg-1 of phosphate buffer (pH 8.0). The eluant was monitored at 350 nm. The calibration graphs were linear over the range from 1×10-8 mol dm-3 to 1×10-6 mol dm-3. The detection limit, defined as 3σ {3-times the standard deviation of the blank value(n=5)}, was 1.3×10-9 mol dm-3. The HPLC method with a laboratory-packed ODS column was applied to iron and certified steel reference materials. The boron contents in the CRMs determined by the proposed method agreed with the guaranteed ones.
Keywords : chromotropic acid; HPLC; boron in iron and steel; certified reference materials; direct determination.
Minemasa Hida, Hiroyasu Satho and Tosiyuki Mitsui*
*Criminal Investigation Laboratory, Aichi Prefecture Police H. Q., Sannomaru, naka-ku, Nagoya 460-8502
(Received 22 June 2001, Accepted 3 September 2001)Pressure-sensitive adhesive cloth tapes were measured by X-ray fluorescence (XRF) and diffraction (XRD) methods. The obtained data were treated with statistical methods, such as cluster analysis and principal-component analysis in order to classify the samples. The surface color of samples was almost ocher, and that of the back surface was almost white. Forty-three samples made by 14 manufactures were analyzed. A multivariate analysis of the XRF and XRD data indicated that the 43 samples could be divided into 5 groups. Samples made by a certain manufacture were classified into one group. In addition to the appearance feature, the cluster analysis and principal-component analysis could be useful for identifying the manufactures. The proposed method could be a promising discrimination method for the tapes often used in serious crimes.
Keywords : pressure-sensitive adhesive cloth tape; multivariate analysis; X-ray fluorescence method; X-ray diffraction method.
Yukiko Okada and Shoji Hirai*
*Department of Energy Science and Engineering, Musashi Institute of Technology, 1-28-1, Tamatsutsumi, Setagaya-ku, Tokyo 158-8557
(Received 23 July 2001, Accepted 8 September 2001)Trace elements in JSAC 0401 and JSAC 0411 certified soil reference materials prepared by the Japan Society for Analytical Chemistry (JSAC) were determined by instrumental neutron activation analysis (INAA). The samples(5-6) were irradiated for 10 sec at a thermal neutron flux of 1.5×1012 ncm-2 s-1 and 6 h at a thermal neutron flux of 3.7×1012 ncm-2 s-1 at Rikkyo University Research Reactor. The irradiated samples were measured by γ-ray spectrometry. The concentrations of 42 elements in JSAC 0401 and of 41 elements in JSAC 0411 were determined. The determined values were in good agreement with the certified values of 8 elements for JSAC 0401 and 7 for JSAC 0411.
Keywords : JSAC 0401 and JSAC 0411 certified soil reference materials; instrumental neutron-activation analysis; g-ray spectrometry; Rikkyo University Research Reactor; certified values.
Yoshihiro Hirano, Hiroki Sakurai, Akihiro Endo, Koichi Oguma* and Yasushi Terui**
*Department of Materials Technology, Faculty of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba 263-8522
**Instruments Group, Analytical Systems Center Design Department, Hitachi Ltd., 882, Ichige, Hitachinaka-shi, Ibaraki 312-8504
A flow injection (FI) on-line preconcentration-graphite furnace atomic absorption spectrometric method was developed for the determination of traces of AsIII and AsV in water. For an AsIII determination, 2 ml of sample was mixed in a FI system with an ammonium pyrrolidinedithiocarbamate (APDC) solution; an AsIII-PDC complex was formed. The complex was adsorbed on a C18 silica gel microcolumn and then eluted with ethanol. The eluate zone containing the highest analyte concentration was injected into the graphite furnace via an autosampler nozzle. After the injection of a Pd matrix modifier solution, AsIII was atomized. The determination of AsV was performed by the same FI system by replacing the APDC solution and ethanol with a Mo-Malachite Green (MG) solution and dimethylsulfoxide (DMSO), respectively. Four milliliters of the sample were mixed with a Mo-MG solution, and the resulting AsV-Mo-MG aggregate was adsorbed on the microcolumn and then eluted with DMSO. The eluate zone containing the highest analyte concentration was injected into a graphite furnace and atomized in the same way as in the AsIII determination. The method was successfully applied to the determination of AsIII and AsV in lake water. The sensitivity enhancement was about 20-fold for both 2 ml of an AsIII solution and 4 ml of an AsV solution. The detection limits, based on three-times the standard deviation of six replicate measurements of a blank solution, were 0.042 and 0.017µg l-1 for AsIII and AsV, respectively. The recoveries were 98±6.5 and 98±6.0%, and the sample throughputs were 15 and 12 samples per hour for AsIII and AsV, respectively.
Keywords : FIA-GFAAS; differential determination; AsIII; AsV.
Yoshitaka Yamaguchi, Noboru Taguchi, Hiroshi Yamanouchi, Toshiaki Shibata, Kazuo Hitomi and Susumu Yamagishi*
*Ship Equipment and Marine Environment Division, National Maritime Research Institute, 6-38-1, Shinkawa, Mitaka-shi, Tokyo 181-0004
(Received 13 July 2001, Accepted 3 October 2001)It is necessary to detect any spilled-oil condition on/in the sea for cleaning and to analyze seawater containing oil for monitoring any micro pollutant in the marine environment. For possible countermeasures, we have developed oil sensors with various configurations for wide scale and real-time monitoring. The first system involves two-dimensional detection applied for a remote sensing (LIDAR) technique and fluorescence analysis. The LIDAR system was used to carry out scanning on the sea surface near Oki Islands onboard an airplane. We succeeded to obtain energy-selected images from the airplane. Furthermore, we tried to analyze micro-contained oil in seawater for a continuous environment analysis onboard a ship. This system can detect oil in seawater at about 50 ppb. We are considering a microanalysis system adapted for monitoring onboard a ship as an observing platform. Our systems are useful for monitoring from macro pollution to micro-contaminated detection in/on the marine environment.
Keywords : fluorescence analysis; oil pollution; marine environment; remote sensing; micro-analysis.
Soichi Yabuki, Fumio Mizutani and Yoshiki Hirata*
*National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1, Higashi, Tsukuba-shi, Ibaraki 305-8566
(Received 12 July 2001, Accepted 4 September 2001)An acetylcholine esterase (AcE)-attached polyion complex membrane containing choline oxidase (ChOD) was prepared, and was used for detecting acetylcholine. The preparation method proceeded for 2 steps. First, a polyion complex membrane containing ChOD wasprepared on a glassy carbon electrode by dropping poly-L-lysine, polystylene sulfonate and ChOD solutions onto the surface. After drying, AcE was bound to the surface of the membrane using glutaraldehyde. The membrane was used to detect acetylcholine; +1 V vs. Ag/AgCl was applied to the electrode to detect produced-hydrogen peroxide. Immediately after the addition of acetylcholine, the oxidative current was increased, and reached a steady state within 15 s. The response current was proportional to the acetylcholine concentration up to 0.2 mM, and the lower detection limit was 5 µM. The interfering current from L-ascorbate was rather small: the current-response ratio from the same concentrations of L-ascorbate and acetylcholine was 60s, because of the restricted penetration of L-ascorbate through the membrane. The long-term stability of the electrode was examined; after 40 days the magnitude of the current response became half of the initial value. Nevertheless, because the form of the calibration curve did not change, the electrode could be used for detecting acetylcholine. Based on these results, the AcE-attached polyion complex membrane containing ChOD can be used for an acetylcholine biosensor.
Keywords : acetylcholine biosensor; polyion complex membrane; enzyme immobilization.
Hiroaki Matsuura*, Fumio Mizutani*,**, Yasushi Hasebe and Shunichi Uchiyama***
*Department of Chemistry, University of Tsukuba, 1-1-1, Tennou-dai, Tsukuba-shi, Ibaraki 305-8571
**National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, 1-1-1, Higashi, Tsukuba-shi, Ibaraki 305-8566
***Department of Applied Chemistry, Faculty of Engineering, Saitama Institute of Technology, 1690, Fusaiji, Okabe, Saitama 369-0293
The frequency fluctuation of a quartz-crystal microbalance (QCM) measurement obtained in the gas phase is significantly smaller than that obtained in the liquid phase. This work has tried to enhance the sensitivity of the QCM measurement of a protein by drying a sample previously bonded at a Au electrode surface on the quartz crystal in the liquid phase. In this method, argon or nitrogen gas was flowed for 25 minutes to dry the sample; excellent stability of the background fluctuation of frequency was obtained. In order to illustrate the present method, albumin, lactate dehydrogenase and monoamine oxidase were chosen as analytes. The linear relationships between the amount of each protein and the frequency changes were obtained below 2.0 µg. Then, anti-bovine albumin was measured using a bovine albumin-immobilized quartz crystal. It was found that the calibration curve of anti-bovine albumin showed a linear line over a weight range from 0.1 to 1.0 µg. The present method requires only a small sample volume, and is able to determine the amount of protein without dilution.
Keywords : quartz-crystal microbalance; detemination of protein in gas phase; suppression of frequency fluctuation.
Kazuhiro Honda, Hidetoshi Arizono, Nobutaka Yamasaki*, Yoshihito Mori, Shyuko Fujieda**, Akira Satoh*** and Seiichiro Nakabayashi****
* Department of Applied Chemistry, Faculty of Engineering, Kanagawa Institute of Technology, 1030, Shimoogino, Atsugi-shi, Kanagawa 243-0292
** Department of Chemistry, Faculty of Science, Ocyanomizu University, 2-1-1, Ohtsuka,Bunkyo-ku, Tokyo 112-8610
*** Department of Electronic Engineering, Faculty of Engineering, Sohnann Institute of Technology, 1-1-25, Tsujidoh-nishikaigan, Fujisawa-shi, Kanagawa 251-0046
**** Department of Chemistry, Faculty of Science, Saitama University, 255, Shimoohkubo, Saitama 338-8570
It was confirmed that silver aggregate produced by redox reaction in strong magnetic field rotated the left cirumference in the vertical surface in the direction of the applied magnetic field. From an image analysis, the aspect which large rotation formed by additional matching of the local rotation of an individual silver particle was observed. The local rotation of an individual one was the motion which originated from the Lorentz force induced by the interaction between the local current which flows by charge polarization and the magnetic field; the surface charge could be decided with the negative from the rotation's direction. Though the angular velocity of the rotation was accelerated along with an increase in the strength of the applied magnetic field, an increase in the ratio was suppressed nonlinearly with the increased one. The electric charge per unit weight of the silver aggregate was estimated to be 0.7 C kg-1, when the calculation considered the nonlinear effect, which assumed dissipation process based on the results of an image data analysis which was carried out.
Keywords : strong magnetic field; silver aggregate; Lorentz force; cyclotron motion; surface charge.
Hirofumi Kawazumi, Takanobu Ukawa and Tomohiro Watanabe*
*Department of Biochemical and Environmental Chemistry, Kyushu School of Engineering, Kinki University, 11-6, Kayanomori, Iizuka-shi, Fukuoka 820-8555
(Received 13 July 2001, Accepted 20 August 2001)Photothermal spectrometry for water is described in which high-power diode laser with a wavelength coincident with strong vibrational overtone absorption in a near-infrared region was used. In the thermal lens technique, an apparatus consisting of only solid-state devices, such as optical fibers, a fiber-coupler and photodiode, was used. The optical fibers acted as not only optical paths, but also as collimation devices. A water content of 0.15% in acetonitrile could be detected, and a linear analytical curve was obtained in the range of 0%~7% with a 1478 nm, 100 mW diode laser at an intensity modulation frequency of 20 Hz. A photoacoustic technique could be also applied to water in acetonitrile and water adsorbed on molecular sieves by using a cell equipped with a cylindrical piezoelectric ceramic. These techniques can be a versatile water-analysis tool for the process monitoring and control.
Keywords : thermal lens; photoacoustic detection; semiconductor laser; optical fiber; adsorbed water analysis.
Akiko Tanabe
Niigata Prefectural Institute of Public Health and Environmental Sciences, 314-1, Sowa, Niigata-shi, Niigata 950-2144
(Awarded by Tokyo University of Pharmacy & Life Science dated July 25, 2000)A gas chromatography-mass spectrometric (GC/MS) method has bean developed for the simultaneous determination of hazardous chemicals. First, a monitoring system of 90 pesticides and 10 transformation products in river water was established; the pesticides in the dissolved phase were extracted with the solid phase and those in the suspended phase were extracted ultrasonically. Second, an optimum analytical conditions of headspace method were examined to the determination of 53 volatile organic compounds (VOCs) in river water and sediment. Last, an ultrasonic extraction method using ethanol-cyclohexane (1:3) was evaluated for the determination of seven polycyclic aromatic hydrocarbons (PAHs) and eight n-alkans in airborne particulate matter. These methods were applied to monitoring the target compounds in Niigata Prefecture. First, in monitoring pesticides in Shinano River, 53 compounds were detected, and the distribution ratios of the pesticides from dissolved phases to the suspended phase seem to depend on the concentrations and properties of the compounds. Second, VOCs were determined for 29 compounds from 16 rivers, and the number of detected VOCs was larger in the winter than in the summer. Last, the concentration levels of PAHs and n-alkanes in airborne particulate matter were evaluated, and anthropogenic sources, including traffic, were the major contributions to the particulates. The results of this study will be available for the monitoring and control of hazardous chemicals suspected to damage human health and ecosystems.
(Received October 2, 2001)Keywords : GC/MS; simultaneous analysis; pesticide; VOC; PAH; n-alkane; river water; airborne particulate matter.
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