Vol. 51 No. 1
January, 2002
Katsuyoshi Hayashi and Osamu Niwa*
* NTT Lifestyle and Environmental Technology Laboratories, 3-1, Morinosato, Wakamiya, Atsugi-shi, Kanagawa 243-0198
(Received 3 September 2001)Electrochemical sensing systems for measuring the concentrations of biomolecules in the brain and neurotransmitters released from cells are reviewed. It is very important to continuously monitor the changes in the biomolecule concentrations in the brain. Many micro-sensing devices have been studied to clarify physiological phenomena in biological systems. The sensitivity, selectivity, and temporal/spatial resolution of these systems must be high. Both microelectrode sensors and on-line sensors are suitable for continuous monitoring; the former can be inserted into the brain or near cells, and the latter can be easily combined with a microdialysis probe, separator, or reactor. In recent years, many researchers have been studying microfabricated chips integrated with channels, separators, detectors and so on. Such chips are called Micro Total Analysis Systems (µ-TAS); it is a new concept concerning biosensing devices. Electrochemical measurement method and neurotransmitters are summarized and application of three types of sensing system to in vivo and in vitro monitoring are discussed.
Keywords : electrochemical measurement method; microelectrode; on-line sensor; µ-TAS; neurotransmitters.
Koji Maehana, Hirofumi Tani *, Tetsuya Kamataki ** and Tamio Kamidate*
* Division of Molecular Chemistry, Graduate School of Engineering, Hokkaido University, Kita-13, Nishi-8, Sapporo, Hokkaido 060-8628
** Division of Medical Pharmacy, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Sapporo, Hokkaido 060-0812
A metal affinity interaction between metals and proteins was exploited for the selective partitioning of histidine-tagged membrane proteins in an aqueous micellar two-phase system. The system used was a mixture of non-ionic surfactant micelle, Triton X-100, and a metal-chelating polymer, Ni(II)-imminodiacetic acid-poly (ethylene glycol) (Ni-IDA-PEG). The mixture separated into two phases, a polymer-enriched upper phase and a micelle-enriched lower phase, under an appropriate condition. The effect of the Ni-IDA-PEG concentration on the partitioning of cytochrome b5 with and without a histidine-tag, and a fluorescein isothiocyanate-labeled oligopeptide containing six histidines was examined in two-phase systems containing various pH buffers. Cytochrome b5 without a histidine-tag was partitioned into a micelle-rich phase, independent of the Ni-IDA-PEG concentration, due to a hydrophobic interaction. On the other hand, with increasing the concentration of Ni-IDA-PEG, the partitioning of histidine-tagged cytochrome b5 was shifted to the polymer-rich phase in a system containing a phosphate or borate buffer. Upon the addition of imidazole to, or the removal of Ni(II) from the two-phase systems, the histidine-tagged protein showed the same partition behavior as that of the protein without a histidine-tag. These results indicate that the metal-chelating polymer plays the role of an affinity ligand, which enables histidine-tagged membrane proteins to move out from the micelle-rich phase to the polymer-rich phase. When Tris was used as a pH buffer, no affinity partitioning of the protein was observed. Although the oligopeptide also partitioned into the polymer phase in the presence of Ni-IDA-PEG, the partitioning was not dependent on the buffer type. Thus, the partitioning seems to be largely affected by the buffer type as well as the protein structure. The present system has a potential for a simple and rapid purification method for the histidine-tagged membrane proteins.
Keywords : aqueous micellar two-phase system; metal-chelating polymer; affinity partitioning; histidine-tagged membrane protein.
Ming Lu*, Toshihiro Horiguchi, Hiroaki Shiraishi, Yasuyuki Shibata**, 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
**Environmental Chemistry Division, National Institute for Environmental Studies, 16-2, Onogawa, Tuskuba-shi, Ibaraki 305-0053
***Faculty of Environmental Studies, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521
A determination method for testosterone in the reproductive organ of an individual shell of a marine gastropod, Thais clavigera, was established by ELISA (enzyme-linked immunosorbent assay). Large deviation in analytical values often encountered in ELISA was overcome both by selecting the ELISA kit used and by extensively purifying the fraction to be analyzed in the pretreatment steps. These resulted in the ELISA values comparable to those by GC/MS. Based on this method, significantly higher testosterone content was confirmed in the female imposex-suffered shells collected from organotin- contaminated seashores than normal ones.
Keywords : ELISA; imposex; marine gastropod; testosterone; Thais clavigera.
Yasuhiko Miyoshi, Akiko Wakabayashi* and Tadashi Hano**
*Basic Research Division, The Tokyo Metropolitan Research Institute for Environmental Protection, 1-7-5, Shinsuna, Koto-Ku, Tokyo 136-0075
**Department of Applied Chemisry, Faculty of Engineering, Oita Universtiy, 700, Dannoharu, Oita 870-1192
A dilution method developed by Miyoshi, et al is sensitive for colored wastewater. In this method all colored wastewater is expressed based on the dilution times; also, their numerical values are understandable for our sensitivities. However this method requires 5 monitors for measurement accuracy, and takes a long time to measure, compared to conventional instrumental methods. Moreover, there are some differences in the measurement results between monitor groups because of using sensitive organs (human eyes). In this paper an instrumental measurement method based on the dilution method is proposed. The instrumental measurement method was developed by using tristimulus values and a sensitive curvature of colored water. The measurement results by this instrumental measurement method well coincided with those of the dilution method. This method could be utilized for the measurement of colored wastewater.
Keywords : dilution method; colored wastewater; instrumental measurement method; sensitive measurement method; tristimulus values
Toshiaki Hiyama*
*Japan Nuclear Cycle Development Institute (JNC), 4-33, Muramatsu, Tokai-mura, Ibaraki 319-1194
(Received 1 October 2001, Accepted 9 November 2001)The simultaneous determination of nitrogen and oxygen in uranium nitride using a thermal conductivity detector and a non-dispersive infrared spectrometer after fusion in an inert gas atmosphere has been proposed. The loss of nitrogen by oxidation of the sample before analysis is prevented by pulverizing, weighing and packing the sample into a nickel capsule in a glove-box with a high-purity argon atmosphere. After the encapsulated sample is transferred into a graphite crucible, it is heated to approximately 2800°C by a resistance heating furnace under a helium carrier gas. The gas extracted from the fused sample is split into about 1/5 and 4/5 by adjusting a pressure regulator and a needle valve. Extracted nitrogen as N2 and oxygen as CO are simultaneously determined by thermal conductivity detector for N2 and non-dispersive infrared spectrometer for CO, respectively. Only 30 mg of the sample is used, and analysis requires about 10 min. No specific skills for glove-box work are necessary. For the determination of uranium nitride, the relative standard deviations have been about 1.2% for nitrogen and 2.7% for oxygen, respectively.
Keywords : nitrogen; oxygen; uranium nitride; inert gas; fusion.
Mikio Kuzuya, Kazushi Hirose* and Takuya Matsuoka**
*Department of Electronic Engineering, College of Engineering, Chubu University, 1200, Matsumoto-cho, Kasugai-shi, Aichi 487-8501
**Tietech Co., Ltd., 2-13-1, Chikamadori, Minami-ku, Nagoya 457-0071
A pyrolysis gas chromatograph system using a pulsed Nd:YAP laser as a fragmentation source was constructed, which allowed for the direct analysis of solid samples. Several solid samples, such as ceramics (BN), coal, and polystyrene, were analyzed to test the performance of the system. The obtained chromatograms showed good reproducibility, and the relative standard deviations of the peak intensity, the FWHM, and the retention time were 1.4%, 2.2%, and 0.5%, respectively. In chromatograms obtained from polystyrene, the characteristic component peaks of benzene, toluene, and styrene monomer were detected. Moreover, a moderate defocusing of laser radiation brought about an increase in the signal intensity. The results showed that the present laser pyrolysis gas chromatograph is applicable to the analysis of solid samples.
Keywords : gas chromatograph; laser pyrolysis; direct analysis; reproducibility; solid samples.
Tomonori Tsuboi, Yoshio Hirano*, Yoshinori Shibata** and Shoji Motomizu***
*The Chugoku Electric Power Co., Inc., Technical Research Center, 3-9-1, Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-0046
**Chuden Kankyo Technos Co., Ltd., 3-9-1, Kagamiyama, Higashi-Hiroshima-shi, Hiroshima 739-0046
***Department of Chemistry, Faculty of Science, Okayama University, 3-1-1, Tsushima-naka, Okayama 700-8530
A flow injection analysis coupled with a gas permeation unit for the sensitive determination of ammonia was investigated to improve the sensitivity and the rapidity of the determination of trace amounts of ammonia in exhaust gas. As gas sampling times are shortened, ammonium concentrations in absorption liquid(boric acid solution) will be lowered; the determination sensitivity of ammonia in the absorption liquid needs to be improved. Various experimental conditions, such as reagent solutions, sample sizes, reaction temperatures, flow rates of the reagent solutions and the length of gas permeation tube, were investigated and optimized. Of these, the reaction temperature and the length of gas permeation tube were found to greatly effect the sensitivity improvement for the determination of ammonia. The effect of the length of the microporous PTFE tube used for the gas permeation system was investigated by varying the length from 5 cm to 50 cm. The results showed that is the 50 cm tube, the peak height was about 6 times higher than in the 10 cm tube, and the percentage of the permeation of ammonia was about 55% and 9% in the 50 cm and 10 cm tube, respectively. Under the optimized conditions, the limit of detection of ammonia was lowered down to on fifth of the previous system. The limit of detection corresponding to the standard deviation of the reagent blank of 3 was 4 µg-1 of NH4+. A calibration graph was linear from 10 µg l-1 to 500 µg l-1 of NH4+. The relative standard deviations for 50 µg l-1 and 100 µg l-1 of NH4+ were 4.5% and 2.3%, respectively. The proposed method was suitably applied to the determination of ammonia in the exhaust gas of the thermal power plant.
Keywords : gas permeation system; ammonia; exhaust gas of a thermal power plant; FIA.
Shuji Wada, Ayumi Nagano, Toshiharu Sato* and Junko Motonaka**
*Taiho Pharmaceutical Co., Ltd., 224-2, Ebisuno, Hiraishi, Kawauchi-cho, Tokushima 771-0194
**Faculty of Engineering, University of Tokushima, 2-1, Minami-Jousanjima, Tokushima 770-8506
Keywords : lubricant oil; assay validation; cleaning of die and punch.
Satoshi Kaneco
Department of Chemistry for Materials, Faculty of Engineering, Mie University, Tsu, Mie 514-8507
(Awarded by Nagoya University dated October 31, 2000)CO2 causes the greenhouse effect and consequent natural disruption of the environment. Therefore, it needs to develop technologies for the sequestration and reduction of CO2. On the other hand, some diseases with the chronic intake of metals at low concentration will possibly become a problem in the future, which means that it is required to develop accurate analytical methods for metals at even lower concentration. Based on these circumstances, the electrochemical or photocatalytic reduction of CO2 released to the environment, and atomic spectrometry for environmental samples were investigated. First, in the electrochemical reduction of CO2 in methanol, the reduction products could be controlled by the selections of supporting electrolytes and cathode materials. Furthermore, the photocatalytic CO2 reduction reaction could proceed in liquid and supercritical CO2 media. Next, a sensitive and accurate analytical method of specific trace metals, such as cobalt, silver and rhodium, in environmental samples by electrothermal atomization atomic absorption spectrometry with a metal tube atomizer was developed. Moreover, a direct determination method of elemental content in individual dried biological cells and particulates by ICP-AES or ICP-MS was investigated. These determination methods may play a significant role in various fields, such as environmental science, pharmacy and biochemistry.
(Received October 9, 2001)Keywords : environment; global warming; carbon dioxide; electrochemical or photocatalytic reduction; atomic spectrometry; trace metal.
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