Vol. 55 No. 8
August, 2006
(Received 28 February 2006, Accepted 27 April 2006)
The present paper describes the development of biosensing methods for extracellular neuronal messengers, L-glutamate and arachidonic acid, and their application to in situ detection in acute brain slices. The methods include and an L-glutamate microsensor based on the capillary action of glass capillaries, an L-glutamate imaging method based on glutamate oxidase-horseradish peroxidase (GluOx-HRP) membranes and an excised patch membrane sensor for arachidonic acid. The L-glutamate microsensor has achieved highly sensitive detection and low sampling volume, which is necessary to minimize physical and chemical perturbations to brain slices. With the GluOx-HRP membrane combined with a difference-image analysis, the time-resolved regional distribution of the L-glutamate flux in acute brain slices was visualized. An in situ sensor for arachidonic acid was developed based on the interaction between arachidonic acid and the phospholipid bilayer of excised patch membranes. The response characteristics of these biosensing methods were studied in terms of the working principle, dynamic range, sensitivity, selectivity and applicability to in situ detection in acute brain slices.
Keywords : L-glutamate microsensor; l-glutamate imaging; arachidonic acid sensor; in situ detection; acute brain slice.
Koji Miyauchi1 and Keiji Saito1
1 UBE Scientific Analysis Laboratory, Inc., 8-1 Goi minamikaigan, Ichihara-shi, Chiba 290-0045(Received 3 March 2006, Accepted 2 May 2006)
The graft structure of maleic anhydride (MA) grafted polypropylene (PP), MA-g-PP, which is an industrial product, was directly characterized by 400 MHz (1H) one- and two-dimensional nuclear magnetic resonance spectroscopy (NMR), which was optimized to characterize the graft structure of industrial MA-g-PP. The NMR analyses demonstrated two graft structures of industrial MA-g-PP. One was the well-known form of single succinic anhydride rings; the other was the anhydride ring attached to the chain terminal via a double bond; the itaconic anhydride (IA)-terminal. All 1H, 13C-NMR chemical shifts of the IA-terminal were first assigned. The grafting MA (g-MA) contents of MA-g-PP were quantified by 1H-NMR. The g-MA contents and the ratios of (IA-terminal/g-MA) of MA-g-PP might be correlated. The decrease in the number-average molecular weight of PP due to the grafting of MA onto PP was thought to be influenced by the reaction, in which the IA-terminal is formed. Within the g-MA contents, 0.05~2.09 mol%, the graft structure did not influence the tacticity of PP.
Keywords : nuclear magnetic resonance spectroscopy; maleic anhydride grafted polypropylene; industrial products; graft structure; itaconic anhydride (IA)-terminal.
Goro Ohba1, Hidekazu Miyahara1, Masato Watanabe1, Eiki Hotta1 and Akitoshi Okino1
1 Department of Energy Sciences, Tokyo Institute of Technology, J2-32, 4259 Nagatuta, Midori-ku, Yokohama-shi, Kanagawa 226-8502(Received 22 December 2005, Accepted 6 May 2006)
A new microplasma source is designed and developed for trace elemental analysis. Inductively coupled plasma (ICP) is generally used as an ionization or excitation source for element analysis. However, because the plasma has a relatively large volume (over 3 cm3), it is not suitable for the analysis of a small amount of samples. Furthermore, because a conventional ICP source can generate only argon plasma, it was difficult to excite or ionize halogen elements. To generate a small volume of argon and helium plasma, a new microplasma source is manufactured and tested. The new microplasma source is a kind of micro hollow cathode configuration. In this plasma source, a stable plasma can be generated at a plasma gas flow rate of 10 to 100 ml/min, and an electric input power of a few watts. The electrodes consist of molybdenum, and a glass insulator of 900 µm thickness is inserted between them. The diameter of the discharge region is 300 µm. The volume of the plasma is much smaller than that of the ICP, and thus a higher volumetric power density can be realized. It is therefore expected that a high analytical sensitivity can be achieved. In the present work, the analytical performance and fundamental plasma properties were investigated mainly by a spectroscopic method. The electron number densities of argon and helium plasma were 5 and 2×1014 cm-3, respectively. The excitation temperature of both the argon and helium plasma were around 3000 K, and these temperatures were almost independent of the input power. Using a helium discharge, the detection limits of fluorine, chlorine and bromine were 8.9, 15 and 9.1 pg, respectively.
Keywords : microplasma; halogen; plasma source.
Akira Matsushita1, Yukio Minami1, Toshiyuki Mitsui2 and Yukihiro Ozaki3
1 Forensic Science Laboratory, Osaka Prefectural Police Headquarters, 1-3-18, Honmachi, Chuo-ku, Osaka-shi, Osaka 541-0053(Received 18 January 2006, Accepted 11 May 2006)
A different calculation method of regression analysis (DCR) can be carried out for the determination of each compound correctly with three or more kinds of compounds in a sample without any separation operation. The determination of DCR is based on the coefficient value of heavy regression, calculated using the measured (corrected) values of known and unknown samples. This time, DCR was used to determine the mixing ratio of the acrylonitrile-butadiene-styrene copolymer (ABS resin) in which acrylonitrile, butadiene, and styrene compounds were mixed. The measured data of NIR spectral analysis was used to analyze the ABS resin. Analyses of ten unknown samples were carried out using four known samples. In this result, the calculated and theoretical values of all unknown samples were approximated closely.
Keywords : different calculation method of regression analysis; synthetic resin; NIR spectral analysis.
(Received 22 February 2006, Accepted 12 May 2006)
The degradation of volatile chlorinated hydrocarbons such as tetrachloroethylene, trichloroethylene and tetrachloromethane, was investigated in aqueous solution using a low-energy ultrasound cleaning bath. In this experiment, no formation of the OH radical was observed, suggesting that no generation of a high temperature cavitation bubble to pyrolyze the water molecule. On the other hand, it was observed that the degradation of tetrachloromethane slowly proceeded during irradiation. To enhance the rate of degradation, we investigated the effect of transition metal powders and frequency of ultrasound. The rate of degradation increased extremely upon the addition of metal powders and was in the order of none<Cu<Fe<Zn. The frequency of the ultrasound also affected the rate of degradation; the order was 100 kHz<45 kHz<28 kHz. These phenomena suggested that a shock wave formed from acoustic cavitation removed an inactive oxide surface of metal powders, resulting in an effective enhancement of the reductive dechlorination reactions.
Keywords : volatile chlorinated hydrocarbons; reductive dechlorination; activation of transition metals; effect of ultrasound frequency, shock wave.
Hiroaki Minamisawa1, Toyohiko Hitoh2, Mayumi Minamisawa3, Masanobu Ando1, Kazunori Saitoh2, Masami Shibukawa2 and Nobumasa Arai1
1 Department of Basic Science and High Technology Research Center, College of Industrial Technology, Nihon University, 2-11-1, Shin-ei, Narashino-shi, Chiba 275-857(Received 13 March 2006, Accepted 1 June 2006)
The properties of chitosan to form a metal complex and dissolve in acetic acid were applied to the preconcentration of Cu(II) in water samples and their determination by graphite furnace atomic absorption spectrometry. A hydrophobic membrane material was formed in the interface between the aqueous phase and nitrobenzene, and trace amounts of Cu(II) in the aqueous phase were quantitatively concentrated in this hydrophobic membrane material at pH range 7.0~10.0 from the aqueous phase. A hydrophobic membrane material containing Cu(II) was separated and dissolved in 2.0 cm3 of 10 mol dm-3 acetic acid. An aliquot of the resulting solution (20 ml) was injected into the graphite furnace. The atomic absorbance of copper in the resulting solution was measured by GFAAS and the ashing temperature and atomizing temperature were selected as 500°C and 2200°C, respectively. The calibration curve was linear in the range of 0.006~0.3 mg of Cu(II) 100 cm3 (r=0.992). The detection limit (3σ) for Cu(II) was 0.002 µg/100 cm3. The relative standard deviation (n=5) was 4.2% for 0.50 µg Cu(II)/100 cm3 and 3.1% for 0.10 µg Cu(II)/100 cm3. The proposed method has been successfully applied to the analysis of trace amounts of Cu(II) in environmental water samples.
Keywords : copper(II); chitosan; interface concentration; nitrobenzene; graphite furnace atomic absorption spectrometry.
Kunihiro Watanabe1, Fumitaka Ichihara1 and Masayuki Itagaki1
1 Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641, Yamazaki, Noda-shi, Chiba 278-8510(Received 7 March 2006, Accepted 11 May 2006)
A novel concentration on-line system for Pb(II) determination has been developed. The method is based on the adsorption of Pb(II) ions on the inner surface of a silica capillary tube (length, 25 m; i.d., 0.53 mm). The metal ions that were concentrated on a silica surface for 180 minutes were eluted on-line with a small amount of diluted nitric acid solution in a carrier line. The flow injection analysis system was composed of four channels, including the carrier, sample, buffer and detection reagent solution. The concentration efficiency of Pb(II), obtained by the present method, was about 910. The eluted Pb(II) ion was then determined with tetraphenyl-porphinetetrasulfonic acid (TPPS) by spectrophotometry. The calibration curve was linear at over the range of 0 to 2.5 ppb. The optimum conditions by the present method were as follows: pH of buffer solution for concentration, 9.5; TPPS, 5.0×10-5 M, pH of TPPS solution, 12; concentration of eluent HNO3, 5.0×10-3 M; volume of the eluent, 10 ml; reaction coil length, 3.5 m; wave-length, 464 nm. The detection limits of Pb(II) was 0.004 ppb. The RSD of 1.5 ppb Pb(II) was 1.4% (n=5). The present method was successfully applied to the determination of trace Pb(II) in river, swamp and tap water samples after masking Fe(III) and Cu(II) with triethanolamine.
Keywords : on-line concentration; silica capillary tube; lead(II); TPPS; FIA.
Yoshinobu Yokoyama1, Keiichi Sato1 and Naoki Furuta1
1 Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27, Kasuga, Bunkyo-ku, Tokyo 112-8551(Received 13 March 2006, Accepted 15 May 2006)
The spectral interferences of polyatomic ions on 56Fe, 63Cu, 64Zn, 75As and 80Se in biological samples were eliminated by an inductively coupled plasma three-dimensional quadrupole mass spectrometer (ICP-3DQMS) equipped with an ion-trap mass spectrometer. Also Fe, Cu, Zn, As and Se in biological samples were determined. The spectral interferences of weak-bonded polyatomic ions, such as 40Ar16O+ (56Fe), 40Ar23Na+ (63Cu), 40Ar35Cl+ (75As), and 40Ar2+ (80Se), were eliminated by optimizing the filter noised field (FNF) function and other operating conditions of 3DQMS. On the other hand, the spectral interferences of strong-bonded polyatomic ions, such as 40Ca16O+ (56Fe), 32S2+ (64Zn) and 79Br1H+ (80Se), were eliminated by optimizing the collision-induced dissociation (CID) function of 3DQMS coupled with optimization of the FNF function. The optimum conditions of the CID voltage and the CID duration time were 0 V and 500 ms, respectively. Under the optimum conditions for the FNF, CID and other operating conditions, Fe, Cu, Zn, As and Se in biological standard materials were determined. It was demonstrated that the analytical results were consistent with the certified values within the standard error. Finally, Fe, Cu, Zn, As and Se in the sampled human serum were determined.
Keywords : inductively coupled plasma; ion-trap mass spectrometer; spectral interferences; collision induced dissociation; biological samples.
Hiroaki Yagoh1, Naoko Take1 and Norio Fukuzaki1
1 Niigata Prefectural Institute of Public Health and Environmental Sciences, 314-1, Sowa, Niigata-shi, Niigata 950-2144(Received 13 February 2006, Accepted 26 May 2006)
In order to expand the applicability of the measurement results of the pH and electrical conductivity of precipitations obtained as a part of environmental education activities, we studied the regional and seasonal variations of the parameters to estimate the dissolved total anions ([An]) and cations ([Cat]) excluding H+, from the pH-values and conductivities. The studied parameters were the concentration-weighted conductivities (lav-cat) of the major cations (Na+, K+, Ca2+, Mg2+ and NH4+) in precipitation on equivalent bases, and the concentration-weighted conductivities (lav-an) of major anions (SO42-, NO3- and Cl-). Relatively small regional and seasonal variations were observed in lav-an; however, remarkable variations were observed in lav-cat, corresponding to the ionic composition ratios of NH4+ and Na+. Lower lav-cat values were obtained in the regions and season in which strong influence by sea salt was observed. This may have come from the regional and seasonal fluctuations of the ionic composition ratios of NH4+ and Na+; there is a large difference between these two ion spices in equivalent conductivities. The annual variations of lav-cat and lav-an were estimated to be about 3 percent and 0.5 percent, respectively. This method was applied to daily collected precipitations at the Niigata-Maki national monitoring station. We evaluated the estimated errors between the measured and calculated [Cat] and [An] using 3-year averaged lav-cat and lav-an for warm and cold seasons separately. Roughly, the monthly, seasonal (warm and cold) and annual average [Cat] and [An] can be estimated within estimation errors of 15 percent from each averaged pH-value and conductivity.
Keywords : precipitation; pH; conductivity; solutes; estimation.
Yoshio Iida1, Mariko Murayama1, Takashi Yarita1, Shozo Asada1, Yasusuke Matsumoto1, Yoshinori Takata1, Yo-ichi Ishibashi1, Hiroyuki Igaki1, Tohru Matsumura1, Satoshi Tsuruta1, Takuzo Takasuga1, Akihiro Ono1, Kazutoshi Kakita1 and Mamoru Sakata1
1 The Japan Society for Analytical Chemistry, 1-26-2, Nishigotanda, Shinagawa-ku, Tokyo 141-0031(Received 30 January 2006, Accepted 22 May 2006)
In the analysis of dioxins (PCDDs, PCDFs and DL-PCBs) whose isomers in total are more than 400 using gas chromatography-mass spectrometry, it is essential to design a suitable gas chromatographic condition to separate the peaks to be measured from other peaks. For this purpose, the literature was surveyed at first to know the separation ability of recent liquid phases for gas chromatographic columns, followed by characterization of experimental data obtained from three interlaboratory testings. A statistical calculation was applied to the results mentioned above to distinguish the separated peaks from the overlapped ones. Confident results were obtained after rejecting data of the overlapped peaks.
Keywords : dioxins; gas chromatographic condition; peak overlapping; statistical calculation; interlaboratory testing.
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