Vol. 54 No. 4
April, 2005
Toshiyuki Osakai1 and Hajime Katano2
1 Department of Chemistry, Faculty of Science, Kobe University, 1-1, Rokkodai, Nada-ku, Kobe-shi, Hyogo 657-8501(Received 30 September 2004, Accepted 2 December 2004)
Recent developments in the electroanalytical chemistry at an oilwater interface have been reviewed by citing literature published mainly in 2002 and 2003. Regarding ion-transfer reactions, some important methodologies have been introduced, which include the uses of new organic solvents and room-temperature molten salts as oil-phase solvents, a three-phase (oilsolid electrodewater) system for the determination of standard Gibbs ion-transfer energies, and some controlled-potential electrolytic cells. Using these new as well as conventional methods, extensive studies have been carried out on the facilitated transfer of cations and anions, the distribution reactions of drugs, and the interfacial transfer of ionic polymers. A previous introduction of scanning electrochemical microscopy has revitalized the kinetic study of electron transfer at oilwater interfaces. A further introduction of new methods, including the electron conductor separating oil-water system, has facilitated the mechanistic study of electron-transfer reactions. Much interest has also been paid to photo-induced electron transfers, the electrodeposition of metallic nanoparticles, etc. In addition, adsorption reactions at oilwater interfaces have been studied by means of in situ electrochemical spectroscopy, and the instability of an oilwater interface has been discussed concerning the relevance of interfacial adsorption of a transferring ion.
Keywords : liquid|liquid interface; ion transfer; electron transfer; adsorption reactions; electroanalytical chemistry.
Hideaki Hisamoto1
1 Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori-cho, Ako-gun, Hyogo 678-1297(Received 6 December 2004, Accepted 31 January 2005)
A recent microfabrication technology opened the new application field such as micro total analysis systems (Micro TAS) or microreactors. These systems employed physical characteristics provided by the liquid microspace, involving short diffusion distance, large surface to volume ratio, or small heat capacity. In contrast to these works, we focused on the chemical functions of highly-selective molecular recognition molecules or functional dyes of which we have been developed, to be integrated into microfluidic chemical sensing systems. The present paper describes our recent results concerning chemical sensing systems based on microfluidic devices. Here, a multi ion sensing system based on the intermittent reagent pumping and ion-pair extraction, a new biosensing scheme based on the enzyme-immobilized polymer membrane, and a novel multi ion sensing scheme based on capillary-assembled microchip, are presented.
Keywords : chemical sensing; ion sensor; microchip; microfluidic device; micro total analysis systems.
Toshiyuki Miyauchi1, Kousuke Uoe1, Tokuhisa Isikawa1, Atuo Tanaka1 and Hidehiko Mori1
1 Department of Applied Chemistry, College of Engineering, Chubu University, 1200, Matumoto-cho, Kasugai-shi, Aichi 487-8501(Received 9 November 2004, Accepted 18 January 2005)
The new type Fe(II) compound, Iron(II)-m-ethyl phosphate-(2-)-o,o'-ethyl phosphonate was prepared by the reaction of diethyl phosphonate with ferric nitrate in an acetonitorile solvent for 2 hours. Fe(II) compound reacted with 1-Naphthol to produce a reddish-purple color (λmax 510 nm). The fundamental conditions of the spectrophotometric method for the determination of 1-naphthol with Fe(II) compound were investigated. Beer's law was obeyed over a concentration range of 2~10 mg/l of 1-naphthol. The optimum pH range was 2.0~3.5, and the apparent molar absorptivity was 1.46×103 l mol-1 cm-1 at 510 nm. The determination of 1-naphthol was not interfered up to 100-times concentration of phenol and 2-naphthol in their presence, respectively. Mono-substitution products of phenol and 2-naphthol were permissible at a one-time concentration of 1-naphthol. The determination of 1-naphthol in the mixtures of 1-naphthol and 2-naphthol was also investigated.
Keywords : diethyl phosphonate; phosphorylation; spectrophtometry; 1-naphthol.
Hiroki Yamazaki1,2, Ryuji Tokugawa2, Masatoshi Osanai2, Touru Torii3, Yoko Mine4, Sinsaku Takayama5, Toshiro Higuchi3 and Eiji Obata1
1 Division of Chemical and Materials Engineering, Muroran Institute of Technology, 27-1, Mizumoto-cho, Muroran-shi, Hokkaido 050-8585(Received 25 October 2004, Accepted 22 December 2004)
This paper describes the development and testing of a single-use multi-sensor system for measuring the concentrations of ions used in nutrition for crops. The sensor consists of a conductive paste material on an insulating PET film; selective ligands can simultaneously measure the concentration of many nutrient ions. It includes electrodes, a heater, a calibration fluid and a waste container, and gives test results within 3 minutes. By using two kinds of sensor systems, pH and EC are measured, together with the concentrations of K+, Ca2+, Mg2+, H2PO4-, NO3- and NH4+. This single-use multi-sensor system is reliable, fast, and easy and inexpensive to use. The single-use multi-sensor system and reference analyzers showed a good correlation for a wide variety of nutrient components.
Keywords : nutrient solution; single-use multi-sensor system; electrochemical sensor; ion-selective electrode.
Yasutada Suzuki1, Takayuki Ito1, Tsugio Fukasawa1, Susumu Kawakubo1 and Masaaki Iwatsuki1
1 Department of Applied Chemistry, Interdisciplinary School of Medicine and Engineering, University of Yamanashi, 4-3-11, Takeda, Kofu-shi, Yamanashi 400-8511(Received 9 December 2004, Accepted 27 January 2005)
Two colorimetric instruments, a photometric titrator and an absorptiometric detector for flow-injection analysis, were developed for experiments in under-graduate course. They were based on the colorimeter using a light-emitting diode (LED) as a light source. The photometric titrator had a holder for a 2-cm cell and a magnetic stirrer. This titrator was applied to titration of Cu(II) and Ca(II) with EDTA. Cu-ammine complex was produced and its absorbance was measured with a red LED (630 nm). The titration curve obtained by this titrator was better than the one obtained by a conventional titrator. Moreover, the volume of the sample and reagents were greatly reduced due to the built-in stirrer. On the other hands, the detector for FIA had a circuit to output flow-signal to a recorder. This detector was applied to the FIA determination of iron in an aluminum sample with 1,10-phenanthroline. Dual-wavelength measurements were performed to reduce the noise caused by peristaltic pumps. From the absorbance at the wavelength absorbed by iron(II) chelate (530 nm), background signal measured at 630 nm was subtracted. The obtained results were good agreement with those by atomic absorption spectrometry. Both instruments had small dimensions (125×90×60 mm) and were low power consumption.
Keywords : compact titrator; compact detector; experiments in undergraduate course; dual-wavelength measurement.
Mikio Ishikuro1
1 Institute for Material Research, Tohoku University, 2-1-1, Katahira, Aoba-ku, Sendai-shi, Miyagi 980-8577(Received 6 September 2004, Accepted 9 December 2004)
Proper dissolution procedures for Fe-Ga-P-C-B-Si bulk metallic glass were investigated for an elemental determination by inductively coupled plasma-optical emission spectrometry (ICP-OES). Metallic samples are usually dissolved with several kinds of mineral acids. For a Fe-Ga-P-C-B-Si bulk metallic glass sample, hydrofluoric acid or hydrochloric acid was not used, because silicon, phosphorus and boron in samples were volatilized. When the sample was dissolved with a mixture of hydrochloric acid and nitric acid, small amounts of black-colored insoluble residue remained. However, by a microwave-assisted dissolution method, the sample was completely dissolved with a mixture of hydrochloric acid, nitric acid and water. Analytical results obtained by ICP-OES had good reproducibility and the total content became almost 100%.
Keywords : Fe-Ga-P-C-B-Si bulk metallic glass; microwave-assisted dissolution method; mixture of HCl-HNO3-H2O; ICP-OES.
Kiyoshi Nakagawa1
1 Depertment of Chemistry, Tokyo Women's Medical University, 8-1, Kawada, Shinjuku-ku, Tokyo 162-8666(Received 9 April 2004, Accepted 31 January 2005)
Trace amounts of nickel, cobalt and manganese in serum were determined by graphite-furnace AAS after a treatment with a high concentration (7.5 M) of ammonia solution. Serum was diluted with ammonia water 2~4 times because the content of these elements in serum was very low and close to the detection limit. This diluted solution was injected with hydrogen peroxide into a graphite furnace. A surfactant was unnecessary because the viscosity of the sample solution was reduced by the treatment with ammonia water. The temperature of the graphite furnace used to make the sample oxidize and to dry it was kept at 80~110°C for 180 s. As a results, the Charateristic Mass (pg/0.0044 Abs) became smaller than that of the recommended method. Ni, Co and Mn concentrations in seronormTM reference human serum were estimated to be 5.49, 1.09 and 10.1 µg/l with % RSD values of 1.1, 1.6 and 5.3, respectively. These values agreed well with the certified values of Ni, Co and Mn.
Keywords : nickel; cobalt; manganese; ammonia solution; graphite-furnace AAS; serum.
Toshiyuki Hobo1, Mariko Murayama1, Shozo Asada1, Hiroyuki Igaki1, Takashi Yarita1, Yohichi Ishibashi1, Satoshi Tsuruta1, Yasusuke Matsumoto1, Kazutoshi Kakita1, Akihiro Ono1 and Mamoru Sakata1
1 The Japan Society for Analytical Chemistry, 1-26-2, Nishigotanda, Shinagawa-ku, Tokyo 141-0031(Received 24 September 2004, Accepted 7 December 2004)
The Japan Society for Analytical Chemistry has developed two new certified reference materials (CRMs) for dioxins: coplanar PCBs and 1~10 chlorinated PCB homologues. A project team has been organized to prepare 2 kinds of marine sediment and to certify the concentration of dioxins and polychlorobiphenyls. An interlaboratory comparison test was performed by participants from 24 laboratories. In a statistical analysis, the z scores in robust method were applied to reject outliers, followed by the usual statistical procedure. The presented CRMs are expected to be useful for the quality assurance and quality control of dioxins analysis.
Keywords : dioxins; PCBs; marine sediment; certified reference material.
Hideshi Ishii1, Naoki Sato1, Motonobu Kawano2, Takamasa Mesaki2 and Jun Kawai1
1 Department of Materials Science and Engineering, Kyoto University, Sakyo-ku, Kyoto-shi, Kyoto 606-8501(Received 29 October 2004, Accepted 20 January 2005)
X-ray fluorescence analysis on rice (brown rice, white rice and wash-free rice) and rice bran has been performed by using a dry battery X-ray fluorescence (XRF) spectrometer in combination with a pyroelectric X-ray generator and a potable Si PIN X-ray detector. As a reference, a similar analysis with a commercial energy dispersion XRF spectrometer achieved the detection of K, Mn, Fe, S, Cu, Zn and Rb. The difference of the XRF spectra revealed that K, Fe, Mn, S and Rb were contained in rice bran. Nevertheless, the dry battery spectrometer detected only K, Mn and Fe; the measured abundances of these elements in rice and rice bran were almost similar. This difference of detected elements is mainly due to the difference between characteristic X-rays from both X-ray sources, and not due to the difference in the intensities of excited X-rays. Thus, the dry battery XRF spectrometer has sufficient capability for the XRF analysis on crops as commercial spectrometers, notwithstanding the low power of the X-ray outputs.
Keywords : X-ray fluorescence analysis; potable; rice; rice bran; dry battery.
Toshihide Matsuda1, Tsuyoshi Hirakawa2 and Hiroshi Sakugawa1
1 Graduate School of Biosphere Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-8521(Received 23 July 2004, Accepted 22 January 2005)
A field-based intercomparison study of a commercial open-path differential optical absorption spectrometer (DOAS) and conventional point monitoring techniques for ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2) was conducted from August to September, 1999, in Higashi-Hiroshima, Hiroshima prefecture. O3, NO2 and SO2 were measured every 10 minutes by an ultraviolet-ray absorption method, a chemiluminescence method, and a fluorescence method, respectively, while all of these three gases were simultaneously monitored every 20 minutes by the DOAS system (DOAS 2000, Thermo Electron Nippon Co. Ltd., Japan). Very good correlations were found for O3 (r2=0.96) and SO2 (r2=0.93), while a slightly lower correlation existed for NO2 (r2=0.80). The average concentrations of these gases monitored by the DOAS system were 1.1, 1.2, 1.6 times higher than those measured by conventional point monitors, respectively. Vehicle emissions from the surrounding area of the monitoring site caused atmospheric inhomogeneities, which were involved in the lower correlation for NO2 by causing differences in the analytical values of the two methods. A much higher slope of SO2 (1.6) was considered to result from the use of an inaccurate standard spectrum in DOAS analysis, which was prepared from 100 ppm level reference gas. Precipitation (0.5~35.0 mm h-1) and the relative humidity (25.6~99.9%) didn't affect the DOAS measurements. Fog interrupted the DOAS measurements of all compounds in during several periods; it occurred when the relative humidity was kept over 99% for a few hours from midnight to morning. The mobile emitting source and the meteorological situations should be considered when monitoring is carried out by DOAS.
Keywords : DOAS; intercomparison; ozone; nitrogen dioxide; sulfur dioxide.
Hideki Sasaki
Mass Spectrometry Technology, Nihon Waters K. K., No. 5 Koike Bldg., 1-3-12, Kitashinagawa, Shinagaw-ku, Tokyo 140-0001
(Awarded by Kanazawa University dated March 25, 2003)
The presented thesis has describes studies on the development of highly sensitive and selective LC/MS methods for the analysis of endocrine disruptors and mycotoxins. A highly selective LC/MS method for the analysis of OH-BaPs was developed. This method was successfully used for the analysis of metabolized samples by CYP1A1/epoxidehydrorase. A highly sensitive LC/MS and FL simultaneous detection method was developed. This method was successfully used to determine aflatoxins added to red pepper at a concentration of 10 mg/kg. The systematic optimization of on-column focusing was established. With this work, improvements in the sensitivity at 30~50 fold by on-column focusing will be routinely achieved. The mechanisms of a shoulder and split peaks appearing when large-volume samples were injected to a LC column were elucidated. A highly sensitive method for detecting trichothecens using LC/MS was developed. This technique, which monitors [M+Na]+ and in which the mobile phase contains NaCl, has a great advantage of being insensitive to variations of the NaCl content in the sample solvent, and is more sensitive than other [M+H]+ monitoring LC/MS methodologies. In conclusion, those developed methods are very useful for the analysis of endocrine disruptors and mycotoxins. In addition, those techniques will be applicable for other LC/MS methods.
(Received January 14, 2005)
Keywords : LC/MS; endocrine disruptor; mycotoxin; hydroxybenzo[a]pyrene; aflatoxin; trichothecen.
Yoshitaka Takagai
Faculty of Symbiotic Systems Science, Fukushima University, 1, Kanayagawa, Fukushima-shi, Fukushima, 960-1296
(Awarded by Ibaraki University dated September 30, 2003)
The high-performance preconcentration method is one of the most important techniques for the ultratrace component analysis. Especially, it can greatly improve the sensitivity and the precision of instrumental analysis. In this study, a homogeneous liquid-liquid extraction method with a perfluoro surfactant was attempted to become available as a preconcentration system for instrumental analysis. Thus, the fundamentals of the phase-separation phenomenon were investigated, and this homogeneous liquid-liquid extraction was applied to capillary electrophoresis (CE) as a preconcentration system. Moreover, an ultra-powerful preconcentration method exceeding ten-million-fold preconcentration was proposed by combining with this homogeneous liquid-liquid extraction method and other different kinds of preconcentration techniques. Environmental and biological analyses have to precisely measure by the reliable analytical method. In this study, new preconcentration and separation methods were created for the purpose of understanding the actual conditions of trace chemical species. Moreover, the presented concepts were applied to not only powerful preconcentration, but also separation and isolation. These approaches could solve serious problems (e.g. sensitivization, selective separation, simple procedure, cost, etc).
(Received December 20, 2004)
Keywords : preconcentration; separation analysis; homogeneous liquid-liquid extraction; capillary electrophoresis.
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