Vol. 14, Supplement A (1998)

Vol. 14, Supplement A (1998)

Proceedings of the 26th Chemical Sensor Symposium
April 4-6, 1998

Abstracts

1.
ゾル溶液から調製したアンチモン酸亜鉛厚膜センサの極低濃度硫化水素に対する検知特性

山田佳博、玉置　純、山本善史、松岡政夫、太田勇夫^*

立命館大理工・日産化学^*

SENSING PROPERTIES TO DILUTE HYDROGEN SULFIDE OF ZINC ANTIMONATE THICK FILM SENSOR PREPARED FROM SOL SOLUTION

Yoshihiro YAMADA, Jun TAMAKI, Yoshifumi YAMAMOTO, Masao MATSUOKA and Isao OHTA^*

Department of Chemistry, Faculty of Science and Engineering, Ritsumeikan University
Kusatsu-shi, Shiga 525-77, Japan
^*Central Research Institute, Nissan Chemical Ind. Ltd.
Funabashi-shi, Chiba 274, Japan

The sensing properties of zinc antimonate（ZnSb₂O₆）thick film sensor have been investigated for detecting dilute H₂S. The ZnSb₂O₆ thick film was prepared by dip-coating into sol solution, in which fine particles (mean size : 20 nm) of zinc antimonate were dispersed, and then calcined in air at 500-1000 ℃. The electrical resistance of the film was the highest when the film was calcined at 900-950 ℃. The film calcined at 900 ℃ showed the highest sensitivity to dilute H₂S down to 0.1 ppm. This film consisted of large particles of 60-100 nm in diameter and had macropores of 100-150 nm. Such microstructure is responsible for good sensing properties. In order to enhance the sensitivity to dilute H₂S, the thinner film was prepared by using twice diluted sol solution. The thinner film could detect H₂S as dilute as 0.01 ppm, which is lower than the threshold concentration of human nose. It is considered that H₂S molecules can diffuse more easily into the inner part of the thinner film.

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2.
SmFeO₃厚膜の表面状態とNO₂ガス応答

青野宏通、エンリコ・トラベルサ^*、ステファノ・ビランチ、定岡芳彦

愛媛大工・ローマ大 "Tor Vergata"^*

SURFACE STRUCTURE AND NO₂ GAS RESPONSE FOR SmFeO₃ THICK FILM

Hiromichi AONO, Enrico TRAVERSA^*, Stefano VILLANTI, Yoshihiko SADAOKA

Department of Materials Science and Engineering, Faculty of Engineering, Ehime University
Matsuyama, 790-77, Japan
^*Department of Chemical Science, and Technology, University of Roma "Tor Vergata"
00133 Roma, Italy

SmFeO₃ thick films were prepared from a mixture of fine SmFeO₃ particles and α-terpineol as an additive. The relationship between surface structure and the sensing characteristics for NO₂ gas were examined for design of the high NO₂ gas sensing materials. The sensitivity was improved when the sample is mixed with large amount of the α-terpineol. The amount of an adsorbed oxygen on the surface of the sample is largely decreased with hold time in vacuo (<10-9 torr) at room temperature for the sample prepared with 4% α-terpineol compared with that with non α-terepineol.

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3.
ビスマス系酸化物半導体を用いた NOセンサ

神川晃幸、酒井　剛、三浦則雄、山添　曻

九大総合理工

NO SENSOR USING BISMUTH-BASED SEMICONDUCTIVE OXIDE

Teruyuki JINKAWA, Go SAKAI, Norio MIURA and Noboru YAMAZOE

Department of Molecular and Material Sciences, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

A search for semiconducting oxides was carried out to design a sensor selective to NO over NO₂. Bi₂O₃ was very selective to NO though not very sensitive among the various oxides examined, and NiO was proved to be the most effective promoter to Bi₂O₃ for enhancing NO sensitivity. The sensor element using 5 wt% NiO-Bi₂O₃ showed fairly good sensing properties to NO in the range of 0-400 ppm in sensitivity, selectivity over NO₂, and response rate, at 300℃. The cross-sensitivities to C₃H₆, C₃H₈, H₂, O₂, and H₂O were modest or insignificant, compared to the sensitivity to NO. Catalytic activity tests and TPD measurements indicated that the response to NO (increase in resistance) was associated with its reaction with the surface oxygen of the element, while that to NO₂ (decrease in resistance) resulted from its anionic adsorption.

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4.
一半導体素子を用いたニオイの識別

高田　義

新コスモス電機

NEW METHOD FOR ODOUR IDENTIFICATION USING ONE SEMICONDUCTOR SENSOR

T. TAKADA

New Cosmos Electric Co.,Ltd.
2-5-4 Mitsuya-naka, Yodogawa-ku, Osaka 532, Japan

Odour identification (or electronic nose) is one of the most attractive objects in gas sensing field. Usually one utilizes plural sensors and analyzes multiple information from the sensors with information processing on CPU. But it is still hard to identify odour species in all circumstances, especially in the case of changing in odour concentration to be detected. We have proposed for gas identification to obtain multiple information from one semiconductor gas sensor, including the information about resistance change, temperature cahnge, capacitance change, inductance change and so on. In this report I will present recent results for odour identification by this method, namely, making a map of (⊿Rm, ⊿Tm) on 2-dimensional space (⊿R, ⊿T), where ⊿Rm and ⊿Tm are obtained from simultaneous measurements of semiconductor resistance change ⊿R and sensor temperature change ⊿T using one SnO₂-based semiconductor gas sensor. Extremely low concentration volatile organic compounds, such as C₆O₆, C₆H₅CH₃ and C₆H₄(CH₃)₂ ranging from 2 ppm to 200 ppm, were discriminated denoting odour identification using one semiconductor gas sensor.

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5.
膜厚およびヘテロ構造を制御した In₂O₃系厚膜型センサの n-C₄H₁₀検知特性

川原昭彦、勝木宏昭、江頭　誠^*

佐賀県窯業技術センター・長崎大工^*

n-C₄H₁₀-SENSING PROPERTIES OF In₂O₃-BASED THICK FILM SENSORS WITH CONTROLLED THICKNESS AND HETEROLAYERED STRUCTURE

Akihiko KAWAHARA, Hiroaki KATSUKI and Makoto EGASHIRA^*

Fine Ceramic Division, Saga Ceramics Research Laboratory
Arita-machi, Nishimatsuura-gun, Saga 844-0024, Japan
^*Faculty of Engineering, Nagasaki University
1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

Gas-sensing properties to n-C₄H₁₀ of pure and noble metal-doped In₂O₃ sensors of thick film type have been investigated. The sensors were fabricated by a slide-off transfer printing method. Thickness and heterolayered structure of the sensors were controlled by stacking slide-off transfer sheets of the same or different oxide layers in a pile, followed by firing at 800℃ in air. Among the sensors examined, a 0.5 wt% Au-loaded In₂O₃ sensor of four stacked layers showed the maximum sensitivity of Rair/Rgas=39.8 to 425 ppm n-C₄H₁₀ at 410℃. It was also found that the sensitivity was dependent on the heterolayered structure; for example, a heterolayered sensor in which a pure In₂O₃ layer was covered with a 0.5 wt% Pt-loaded In₂O₃ layer was more sensitive than a sensor with the reverse sequence of stacking.

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6.
バリスタ型ガスセンサの交流インピーダンス法によるガス検知機構の解明

兵頭健生、金沢英一、高尾雄二^*、清水康博、江頭　誠

長崎大工、環境^*

GAS-SENSING MECHANISM OF VARISTOR-TYPE GAS SENSOR　BY A. C. IMPEDANCE TECHNIQUE

Takeo HYODO, Eiichi KANAZAWA, Yuji TAKAO^* Yasuhiro SHIMIZU and Makoto EGASHIRA

Faculty of Engineering, ^*Faculty of Environmental Studies, Nagasaki University
1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

H₂-sensing mechanism of Nb₂O₅-based varistor gas sensor was investigated by means of a. c. impedance technique. Resistance components of Nb₂O₅ were decomposed into four elements, (i) electrical bulk resistance (R₀), (ii) grain boundary resistance (R₁), (iii) resistance of oxide ion conductivity (R₂) and (iv) electrode-oxide interface resistance (R₃).
The R₁, R₂ and R₃ elements decreased drastically with increasing H₂ concentration, while the R₀ element remained almost unchanged in air at 400 C. At 700 C, however, little change was observed for all the four elements with the pressure of H₂.
This behavior is well correlated with the changes of breakdown voltage of Nb₂O₅.
Further studies have confirmed that R₁ is the most important factor determining breakdown voltage of Bi₂O₃-added Nb₂O₅ under different H₂ concentration in air at 400ーC .

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7.
水素選択性熱線型半導体式センサ

福井清、勝木章

新コスモス電機株式会社

H₂ SELECTIVE HOT WIRE SEMICONDUCTOR TYPE GAS SENSOR

Kiyoshi FUKUI and Akira KATSUKI

New Cosmos Electric Co.,Ltd.
2-5-4 Mitsuya-Naka, Yodogawa-Ku, Osaka 532-0036, Japan

A highly selective H₂ gas sensor was developed based on "Hot Wire Type" gas sensor. Tin oxide was sintered in a bead (0.50mmφ) covering over a platinum wire (0.02mmφ) coil. A dense layer with ca.0.1mm in depth near the surface of the porous bead was formed by chemical vapor deposition(CVD) of hexamethyldisiloxane(HMDS).The dense layer functioned as "molecular sieve", thereby the diffusion of gases with large molecular diameters except for H₂ was effectively controlled, resulting in a prominent selectivity to H₂. A counterpart against a strong reduction with H₂ due to the system was investigated; the H₂ selective gas sensor thus obtained had a significantly minor humidity dependence and a prominent long term stability.

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8.
酸化スズ系センサにおける湿度依存性の改善

　福井清、勝木章

新コスモス電機株式会社

IMPROVEMENT OF HUMIDITY DEPENDENCE IN GAS SENSOR BASED ON SnO₂

Kiyoshi FUKUI and Akira KATSUKI

New Cosmos Electric Co., Ltd.
2-5-4 Mitsuya-Naka, Yodogawa-Ku, Osaka 532-0036, Japan

A gas sensor with a minor humidity dependence was developed on the basis of "Hot Wire Type" gas sensor. Tin oxide powder was sintered in a bead (0.55 mmφ) to cover a platinum wire (0.020 mmφ) coil; and the addition effects of various metal oxides on humidity dependence were investigated in laboratory and in outdoor operation through a year.

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t1.
薄膜技術と自動車への応用

多賀康訓

豊田中研

THIN FILM TECHNOLOGY AND APPLICATIONS TO AUTOMOBILE

Yasunori TAGA

Toyota Central Rsearch and Development Laboratories, Inc.
Nagakute, Aichi 480-1192, Japan

This review paper first describes a new concept of the thin film process in material synthesis on the basis of ion-surface interaction during deposition. Some examples of practical applications of various thin film sensors to automobiles are then given. They include GMR films for speed sensors, thin film oxygen sensors and NO_x sensors. Finally, further challenges to applications of thin films to the automobile sensors are discussed.

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j1.
環境保全用を中心とする新しい高性能ガスセンサの研究開発

三浦則雄

九州大学総合理工

DEVELOPMENT OF NEW TYPE HIGH-PERFORMANCE GAS SENSORS FOR ENVIRONMENTAL PROTECTION

Norio MIURA

Department of Molecular and Material Sciences, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

The results of our approaches to high-performance gas sensors for environmental protection are briefly reviewed. The gas sensors developed are classified into five groups, i.e., solid-state gas sensors operative at room temperature, potentiometric sensors coupling solid electrolyte and auxiliary phase, novel amperometric sensors based on solid electrolyte, mixed-potential-type sensors using oxide electrodes for high-temperature operation, and oxide semiconductor sensors using newly designed materials. High performances of these sensors in sensitivity and selectivity have been demonstrated for oxygenic gases (CO₂, CO, NO₂, NO and SO₂), offensive odors (NH₃, H₂S, and Cl₂) or combustible gases (H₂ and C₂H₅OH).

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j2.
ジルコニアセラミックを用いた高温湿度計の開発

八木秀明

日本特殊陶業株式会社

HIGH TEMPERATURE HUMIDITY SENSOR USING A LIMITING CURRENT TYPE PLANE OXYGEN SENSOR

Hideaki Yagi

Advanced Products Development, Technical Ceramic Group, NGK SPARK PLUG CO., LTD.
Komaki-shi, Aichi 485-8510, Japan

A high-temperature humidity sensor for use in ambient atmospheres has been deloped, the first in industry, using a limiting-current zirconia electolyte planar oxygen sensor which both anode and cathode electrodes are arranged on a same plane of the ZrO₂ and the cathode also serves as a hole to limit gas diffusion. However, the above sensor cannot used for direct firing or combustion systems. We have now developed a multisensor capable of measuring both the humidity and oxygen content simultaneously by further improving the features of the planar electrode configuration of the above sensor. We verify that practical high-temperature humidity sensors can be realized for use in direct firing or combustion systems by using this multisensor.

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9.
電池駆動型 SnO₂系 COセンサ

藤森裕樹、木虎真紀、野村徹、中原　毅、松浦吉展、麻生　功

フィガロ技研

BATTERY OPERATED CO SENSOR BASED ON SnO₂

Yuki FUJIMORI, Maki KITORA, Tohru NOMURA, Takeshi NAKAHARA, Yoshinobu MATSUURA and Isao ASO

Figaro Engineering Inc.
1-5-11 Senbanishi Mino, Osaka 562-8505, Japan

To develop the pulse heated semiconductor CO sensor which operates on a 9V alkaline battery for two years (average power consumption ; approximately 0.1 mW), the current sensor structure was refined. The results regarding thermal analysis of the sensing element convinced us that temperature gradients of this element was so large that only a small area was cleaned by heating. Furthermore, it was found that the loss due to heat conduction , mainly through Au electrodes, was larger than expected. From these results, the element size was reduced from 0.5×0.5 mm to 0.3×0.3 mm, and Pt was used for the electrode material. Compared with the current sensor, the modified sensor was drastically improved as to the long term stability under battery operating conditions.

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10.
酸化スズ系ガスセンサ出力と室内温熱環境指数の関係

大藪多可志，小野寺武^*，松浦吉展^**，大藪邦男^***

金沢経済大，金沢大・工^*，フィガロ技研^**，大藪建設^***

CHARACTERISTICS OF GAS SENSOR OUTPUT AND INDOOR THERMAL INDEX IN AWAKENING

Takashi OYABU, Takeshi ONODERA^*, Yoshinobu MATSUURA^** and Kunio OYABU^***

Kanazawa College of Economics
Gosho-machi, Kanazawa 920-0813, Japan
^*Kanazawa University
Kodatuno, Kanazawa 920-8667, Japan
^**Figaro Engineering
Minoo-shi, Osaka 562-0036, Japan
^***Oyabu Kensetu
Unazuki, Toyama 938-0862, Japan

Outputs of tin oxide gas sensors are influenced by room temperature and humidity. The relations among the sensor output, temperature and humidity in an indoor environment are examined. These data are measured at awakening because the air quality is clean at the time. The relation between the sensor output and room temperature has a positive correlation coefficient. The relation between the sensor output and humidity in an air tight structure house does not have a correlation. Daily mean temperature and the sensor output also has a positive correlation. The system can reason a daily mean temperature from the sensor output using AI rules.

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11.
酸化スズを用いた熱線型半導体式 CO選択性センサ

佐藤武司、三橋弘和、高橋祥夫

新コスモス電機(株)

HOT WIRE SEMICONDUCTOR TYPE CO SELECTIVE GAS SENSOR USING TIN OXIDE

Takeshi SATO, Hirokazu MITSUHASHI and Sachio TAKAHASHI

New Cosmos Electric Co.,Ltd.
2-5-4 Mitsuya-naka, Yodogawa-ku, Osaka-city 532-0036, Japan

Hot wire semiconductor type CO selective gas sensor was developed by using sintered tin oxide. The addition effects of lead oxide and rare-earth metal oxides on the CO selectivity of the tin oxide semiconductor were examined, in order to improve the selectivity to CO against H₂ and hydrocarbon(i-C₄H₁₀). The maximum selectivity to CO was obtained on addition of 0.2 atm% PbO_x and 0.5 atm% Nd₂O₃. This sensor had high sensitivity and selectivity to CO even at high sensor temperature of 300℃, and also a quick response to CO. The sensitivity to CO in 500ppm was higher than that to H₂ and i-C₄H₁₀ in 1000ppm. The sensitivity to CO was not almost affected by variation of ambient temperature and humidity. The long term stability had been confirmed for a year.

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12.
自動車用自動換気装置の試作

中川英元、岡崎慎司、福田健三、朝倉祝治、秋本英雄^*、重盛徹志^**、高橋祥夫^**

横浜国大・工、エーシーイー^*、新コスモス電機^**

DEVELOPMENT OF AN AUTOMATIC VENTILATION SYSTEM

Hidemoto NAKAGAWA, Shinji OKAZAKI, Kenzo FUKUDA, Shukuji ASAKURA, Hideo AKIMOTO^*, Tesshi SHIGEMORI^**, Sachio TAKAHASHI^**

Dept. of Mater. Sci. & Chem. Eng., Yokohama National Univ.
^*Advanced Circuit Eng. Co.
^**New Cosmos Electric Co. Ltd.

The application of gas sensors to an automatic ventilation system for a vehicle is reported. Three gas sensors were adopted for air quality monitoring: an NO₂ sensor and a hydro-carbon gas sensor for outside air, an odor sensor for inside air. The NO₂ sensor is aimed for diesel exhaust gas and the hydro-carbon gas sensor is aimed for the residue gas of gasoline and diesel engines. These sensors require high sensitivities and effects of the humidity interference were invested. High concentration of NO₂ gas was found in diesel exhaust gas. Test drive data are presented.

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13.
酸化物電極を用いた固体電解質型 NO_xセンサの検出感度制御

中村忠司，佐治啓市，山下勝次

豊田中研

SENSITIVITY CONTROL OF SOLID ELECTROLYTE NO_x SENSOR ATTACHED WITH OXIDE ELECTRODE

Tadashi NAKAMURA, Keiichi SAJI and Katsuji YAMASHITA

Toyota Central Research & Development Labs., Inc.
Nagakute, Aichi 480-1192, Japan

Current(I)-voltage(V) characteristics of a zirconia-based electrochemical cell with a Pt electrode and an oxide electrode such as Fe2O3 have been investigated in NO_x-O₂-N₂ mixtures at temperatures higher than 600℃. With the addition of NOx to O₂-N₂ mixtures, the I-V curves shifted and the current change depended on the applied voltages to the cell. Based on these characteristics, a new technique for controlling NO_x sensitivity has been developed, in which the constant current is applied to the cell, and the voltage between two electrodes is measured as a sensor output. The sensitivity to NO and NO₂ could be controlled by the magnitude and the polarity of applied currents to the sensing cell. Under the condition of anodic polarization, the sensing cell with Fe₂O₃ electrode could respond well up to 300ppm NO independent of coexistent NO₂ at 700℃.

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14.
Pb-Ru-O系パイロクロア型酸化物電極を用いた固体電解質 NO_xセンサ

清水陽一、西　裕美、山下南美

九工大工

SOLID ELECTROLYTE NO_x SENSOR USING Pb-Ru-BASED PYROCHLORE-TYPE OXIDE ELECTRODE

Youichi SHIMIZU^*, Hiromi NISHI and Nami YAMASHITA

Department of Applied Chemistry, Kyushu Institute of Technology
1-1 Sensui-cho, Tobata, Kitakyushu 804-0015, Japan

Solid electrolyte NO_x sensors using pyrochlore-type oxide (Pb_2-xA'_xRu_2-yB'_yO_7-z: A'= Bi, Sn; B'= V, Pb; x, y = 0 - 0.75) electrodes and NASICON-discs have been investigated for the detection of NO and NO₂ in the range 10-1000 ppm at 400℃. The most of the elements attached with the pyrochlore-type oxide electrodes showed good EMF responses to the sample gases containing NO or NO₂, showing almost linear to the logarithm of NO or NO₂ concentration, while the value and slope of the EMF responses, the electrode reactions, were changed drastically depending on the electrode materials. The device attached with Pb₂Ru_1.9V_0.1O_7-z electrode gave best response performance to NO and NO₂, i.e., the 90% response time to 500 ppm NO or 110 ppm NO₂ was as short as 0.5　min or 1　min, respectively.

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15.
混成電位を利用したプロピレンセンサの開発

日比野高士、桑原　好孝

名古屋工業技術研究所

PROPYLENE SENSOR BASED ON MIXED POTENTIAL

Takashi HIBINO and Yositaka KUWAHARA

National Industrial Research Institute of Nagoya
Hirate-cho, Kita-ku, Nagoya 462-8510, Japan

A potentiometric sensor detecting propylene under oxidizing atmospheres has been constructed from a YSZ with gold and platinum electrodes. When the sample gas containing 500ppm propylene and 10% oxygen was fed into either the gold or platinum electrode compartment at 600℃,the mixed potential of the gold electrode against the reference electrode exposed to air was -103 mV, but that of the platinum electrode was -15 mV. It was also found that the mixed potentisl of the gold electrode was independent of the coexistence of water vapor and carbon dioxide and that its value to 500ppm methane, hydrogen or carbon monoxide was about -35mV. Furthermore, a single-compartment cell with the gold and platinum electrodes enabled one to decrease drastically the influence by changing oxygen concentration.

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16.
分極方式 NO_xセンサの作動機構と感度特性

高　云智、厳　永鉄、国元　晃、三浦　則雄、山添　曻

（株）リケン、九大総合理工

WORKING MECHANISM AND SENSING CHARACTERISTICS OF POLARIZATION TYPE NO_x SENSOR

Yunzhi GAO, Yongtie Yan, Akira KUNIMOTO, Norio MIURA and Noboru YAMAZOE

Research & Development Division, Riken Corporation
Kumagaya-shi, Saitama 360, Japan
Department of Materials Science and Technology, Graduate School of Engineering Sciences, Kyushu University
Kasuka-shi, Fukuoka 816, Japan

A potentiometric solid-state sensor using stabilized zirconia and Pt-M alloy sensing electrode was examined for detection of NO_x at high temperatures. The sensor showed quick potential response and NO_x totality to NO and NO₂ at 550-650℃, if the overpotential of sensing electrode was polarized at 50-150 mV vs. the Pt reference electrode by constant current in 4%O₂ only. The potential response is in proportion to logarithmic function of NO_x concentration in the range of 0-500 ppm.

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17.
Na⁺ 導電体(NASICON)を用いた全 NO_x 計測用アンペロメトリックセンサ

小野正樹、島ノ江憲剛、三浦則雄、山添　曻

九大総合理工

AMPEROMETRIC SENSOR BASED ON Na⁺ CONDUCTOR (NASICON) FOR DETECTION OF TOTAL NO_x

Masaki ONO, Kengo SHIMANOE, Norio MIURA and Noboru YAMAZOE

Department of Molecular and Material Sciences, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

A Na⁺ conductor (NASICON) based-amperometric sensor of three-electrode type was designed for the detection of total NO_x (NO + NO₂) in air. In order to make the device sensitive to NO, the Au sensing electrode was covered with double catalyst layers, i.e., a layer of 0.5 wt% Pt-loaded SiO₂ stacking on a layer of WO₃, to oxidize NO to NO₂. The sensing electrode was polarized at -150 mV vs. the Au reference-electrode, and then the electric current flowing between the sensing and counter electrodes was measured as a sensing signal at 150℃. The current response was perfectly proportional to the concentration of NO₂ or NO up to 1 ppm. In addition, the proportionality constants (sensitivity) were almost the same to NO and NO₂.
The current responses to NO₂ and NO were hardly affected by the coexistence of CO₂ and H₂O. The NO_x sensing mechanism of the present sensor was briefly discussed.

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18.
白金検出極を用いた PbCl₂固体電解質系常温型塩素ガスセンサ

新関良夫、柴田茂雄

東北工大

ORDINARY TEMPERATURE TYPE CHLORINE GAS SENSOR USING PbCl₂ SOLID ELECTROLYTE AND Pt-BLACK SENSING ELECTRODE

Yoshio NIIZEKI and Shigeo SHIBATA

Faculty of Engineering, Tohoku Institute of Technology
6 Hutatsusawa, Taihaku-ku, Sendai 982-8588, Japan

A ordinary temperature type chlorine gas sensor of the following galvanic cell type using Pt-black as a sensing electrode has been made： Pb │ PbCl₂＋1 mol％ K₂SO₄＋10 mol％ Al₂O₃ │ Pt-black, Cl₂(x ％)． The sensing characteristics of the sensor followed Nernst's equation very well in the wide concentration range of 5 ppm to 100％　of chlorine in N₂ and air at ordinary temperature. The 90％ response times were less than ca.10 sec in the centration range covered.

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19.
ニトロソニウムイオンを伝導種とする固体電解質を用いた NO_xセンサ

山本貴生、田村真治、今中信人、足立吟也

阪大院工

NO_x SENSOR BASED ON NITROSONIUM ION CONDUCTING SOLID ELECTROLYTES

Takao YAMAMOTO, Shinji TAMURA, Nobuhito IMANAKA and Gin-ya ADACHI

Department of Applied Chemistry, Faculty of Engineering, Osaka University 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan

A NO_x sensor was fabricated with the combination of NO⁺-Ga₁₁O₁₇ and sodium nitrite as a solid electrolyte and a reference electrode, respectively. NO⁺-Ga₁₁O₁₇ was prepared by ion-exchanging K⁺ and Rb⁺ in (K⁺, Rb⁺)-Ga₁₁O₁₇ for NO⁺ by immersing (K⁺, Rb⁺)-Ga₁₁O₁₇ pellets into NOCl・AlCl₃ melt. From the electrical conductivity and FT-IR spectroscopy measurements, the ion exchange from K⁺, Rb⁺ to NO⁺ in the gallate was identified. The sensor responded exactly to the Nernst relationship for the NO concentration from 0.5 to 10 ppm.

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20.
CO₂－O₂雰囲気中の Au/Li₂CO₃系電極反応機構

照井茂樹、開米篤志、河村憲一、二唐裕、川田達也、水崎純一郎、田川博章^*

東北大科研・環境エネルギー科研^*

ELECTRODE REACTION AT THE Au/Li₂CO₃ INTERFACE IN THE CO₂-O₂ ATMOSPHERE

Shigeki TERUI, Atushi KAIMAI, Kenichi KAWAMURA, Yutaka NIGARA, Tatuya KAWADA, Junichiro MIZUSAKI and Hiroaki TAGAWA

Research Institute for Scientific Measurements, Tohoku University
2-1-1 katahira, Aoba-ku, Sendai, 980-8577, Japan

In order to reveal the electrode reaction at the CO₂, O₂, Au / Li₂CO₃ interface, which is considered to influence the response rate of a solid electrolyte type CO₂ sensor, electrode impedance was measured. The interface conductivity, σE, was strongly depended on PO₂, proportional to (PO₂)‐1/2 in the high PO₂ region and （PO₂）0 in the low region. Dependence of σE on PCO₂ was very weak. TheσE could be formulated to σE＝1/[A(PO₂)‐1/2(PCO₂)1/4＋B(PCO₂)‐1/4], where A and B were constants depending only on the temperature. The interface capacitance, CE, was almost independent of the gas composition and temperature. Therefore the sensor response rate τ(= CE / SσE), where S is apparent contact area between the electrode and the solid electrolyte, is mainly affected by PO₂ because of the dependency of σE on PO₂.

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21.
NASICONと Li₂CO₃-CaCO₃補助相を用いた CO₂センサの応答特性と界面構造

島ノ江憲剛、川手秀樹、三浦則雄、山添　曻

九大総合理工

INTERFACE STRUCTURE OF CO₂ SENSING DEVICES USING Li₂CO₃-CaCO₃/NASICON JUNCTION

Kengo SHIMANOE, Hideki KAWATE, Norio MIURA and Noboru YAMAZOE

Department of Molecular and Material Sciences,Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

Potentiometric devices combining NASICON (Na⁺ conductor, Na₃Zr₂Si₂PO₁₂) with a series of Li₂CO₃-CaCO₃ phases were investigated for CO₂ sensing properties and hetero-junction structure involved. It was revealed that the excessive addition of CaCO₃ in combination with the auxiliary layer fabrication by a melt-quench method at higher temperature was effective for improving the CO₂ sensing capability at lower temperatures: Li₂CO₃-CaCO₃ (1:2) allowed normal operation down to 300℃ while Li₂CO₃ did down to 350℃.
The analyses of the fractured surfaces by means of an electron-probe micro-analysis and SEM indicated the formation of an interfacial layer between NASICON and carbonates, the thickness and structure of which depended on the carbonate compositions used. As revealed by X-ray diffraction analysis, CaZrO₃ was formed between NASICON and Li₂CO₃-CaCO₃ (1:1～2), suggesting its relevance to the lower temperature sensing capability.

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22.
CeO₂／BaCO₃／CuOを用いた炭酸ガスセンサの開発

森本信司、松原正吾、志水章一、金子信一郎、石原達巳^*、滝田祐作^*

九州松下電器・大分大学工^*

DEVELOPMENT OF CO₂ SENSOR BASED ON CeO₂/BaCO₃/CuO-MIXED OXIDES

Shinji MORIMOTO, Shogo MATSUBARA, Shoichi SHIMIZU, Shinichiro KANEKO, Tatsumi ISHIHARA^* and Yusaku TAKITA^*

Material & Component Research Lab., Kyushu Matsushita Electric Co., Ltd.
Fukuoka-shi, Fukuoka 812-8531, Japan
^*Faculty of Engineering, Oita University
Oita-shi, Oita 870-1192, Japan

CO₂ sensors with high humidity-resistance and at low-cost have been demanded in the fields of IAQ(Indoor air quality) monitoring, controlled ventilation and plant growth systems. Capacitive type CO₂ sensors comprising CeO₂/BaCO₃/CuO-mixed oxides have been developed. They have good stability in CO₂ sensitivity under 85℃90% RH test for 1,500 hours. The practical characteristics were measured by a CO₂ sensing monitor with an oscillation circuit using this sensor. It was shown that the sensitivity change was negligible between 0% RH and 60% RH at 30℃. The measurement error of CO₂ concentration was within 200 ppm in the humidity range of 40% to 90% RH, and within 30 ppm/℃ in the temperature range of 5℃ to 50℃. These results show that the developed CO₂ sensor may be applicable to IAQ monitoring systems.

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23.
静電容量型炭酸ガスセンサの検知機構の考察

松原正吾、金子信一郎、森本信司、志水章一、石原達巳^*、滝田祐作^*

九州松下電器・大分大学^*

A SENSING MECHANISM OF DEVELOPED CAPACITIVE-TYPE CARBON DIOXIDE GAS SENSORS

Shogo MATSUBARA, Shinichiro KANEKO, Shinji MORIMOTO,Shoichi SHIMIZU, Tatsumi ISHIHARA and Yusaku TAKITA

Material&Component Research Laboratory, Kyushu Matsushita Electric Co., LTD.
Fukuoka 812-8531, Japan

To understand a sensing mechanism of capacitive-type CO₂ sensors such as CeO₂/BaCO₃/CuO and BaTiO₃/BaCO₃/CuO, DC characteristics of BaTiO₃/BaCO₃/CuO, BaTiO₃ and CuO was investigated in terms of atmosphere gases, electrode material, and doping. The resistance of BaTiO₃/BaCO₃/CuO depended strongly on atmosphere gases of O₂, 10%CO₂/O₂, and N₂, which suggested O₂ adsorption might be an essential reaction in the CO₂ sensing. The 2000 ppm CO₂ sensitivity of the BaTiO₃/BaCO₃/CuO with Ag, Au and Pt electrodes were, +3.5 dB , -0.7dB and -1.2 dB, respectively. From these result, it was suggested that the electrical property of BaTiO₃/BaCO₃/CuO was controlled by a metal-semiconductor contact , and the barrier height would vary with O₂ adsorption volume resulted from an interaction in CuO1-δ-Oad-CO₂.

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24.
分子鋳型法を用いた CuO-BaTiO₃複合酸化物の作製と容量型CO₂センサ

高木俊昭、石原達己、樋口正和、伊藤正実^*、滝田祐作

大分大工・大分大地域共同研究センター^*

CAPACITIVE TYPE CO₂ SENSOR OF CuO-BaTiO₃ PREPARED WITH SELF-ASSEMBLED MULTIBILAYER FILM

Toshiaki TAKAGI, Tatsumi ISHIHARA, Masakazu HIGUTHI, Masami ITO^* and Yusaku TAKITA

Department of Applied Chemistry, Faculty of Engineering, Oita University
700 Dannoharu, Oita 870-1124, Japan
^*Research and Development Center, Oita University
700 Dannoharu, Oita 870-1192, Japan

Preparation of CuO thin film by the decomposition of self-assembled multibilayer film as molecular template was investigated. Furthermore, CO₂ sensing property of resultant CuO thin film on porous BaTiO₃ was investigated as capacitive type sensor. Self-assembled bilayer film of few 1000layers thickness can be obtained easily by casting an aqueous suspension composed of dimethyldihexadecylammoiun bromaide (DC-1-16), Cu(CH₃COO)₂, hexadecane(ethyleneamino)amine, and polyvinyle alcohol. Quick heat to the combustion temperature of DC-1-16 is desirable for removing organic molecules in multibilayer as a template. Thin film of CuO can be obtained by calcination at temperature higher than 573 K. The capacitance of CuO thin film prepared by self-assembled multibilayer film as molecular template on BaTiO₃ porous substrate exhibits a high sensitivity to CO₂, which is twice higher than that of conventional mixed oxide capacitor of CuO-BaTiO₃. Furthermore, it was suggested that regularity of Cu²⁺ in bilayer film is important to improve the sensitivity.

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25.
Pt/WO₃膜のライン型光ファイバ水素センサへの適用

関本慎二郎、岡崎慎司、中川英元、朝倉祝治、福田健三、重盛徹志^*、高橋祥夫^*

横浜国大工、新コスモス電機^*

THE APPLICATION OF Pt/WO₃ THIN FILM TO A FIBER-OPTIC EVABESCEBT-WAVE HYDROGEN GAS SENSOR.

Shinjiro SEKIMOTO, Shinji OKAZAKI, Hidemoto NAKAGAWA, Shukuji ASAKURA, Kenzoh FUKUDA, Tessi SIGEMORI^* and Sachio TAKAHASI^*

Yokohama National University
Hodogaya-ku, Yokohama 240, Japan
^*New Cosmos Electric Co.

An optical-fiber evanescent-wave hydrogen gas sensor was developed and characterized. The sensor utilizes the absorption change of the evanescent field in the clad region of the fiber. A sol-gel process was used to coat the coloring media Pt/WO₃ on the surface of the core. When the sensor was exposed to hydrogen gas, the increase in optical transmission power was observed around 800 nm, and the decrease was observed around 500 nm, as a result of the formation of blue tungsten bronze. The sensor responded to hydrogen gas sensitively. It has been found that the sol-gel process is very promising of an optical fiber hydrogen sensor.

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26.
プラズマ酸化法で調製した酸化ニッケル薄膜による光学的湿度検知

安藤昌儀、佐藤義幸、田村繁治、小林哲彦

大工研

OPTICAL HUMIDITY DETECTION BY USE OF PLASMA-OXIDIZED NICKEL OXIDE FILM

Masanori ANDO, Yoshiyuki SATO, Shigeharu TAMURA and Tetsuhiko KOBAYASHI

Osaka National Research Institute, AIST, MITI,
1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan

We report on the optical humidity detection by use of nickel oxide (NiO) film prepared by plasma oxidation of nickel-carbon composite film. The plasma-oxidized NiO film showed humidity-sensitive absorbance change at room temperature. The optical absorbance change was strongest at wavelengths around 560 nm. The reversible absorbance change over a wide humidity range of 0-90% RH and the response time within several minutes make the plasma-oxidized NiO film a potential candidate for optical humidity detection.

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27.
可溶性ポリアニリン/ポリビニルアルコール複合膜の乾湿応答とその共存ガスによる影響

才野貴之、椎木　弘、中山雅晴、小倉興太郎

山口大工

EFFECT OF VARIOUS GASES ON THE RESPONSE OF THE SOLUBLE POLYANILINE / POLY(VINYL ALCOHOL) COMPOSITE TO HUMIDITY

Takayuki SAINO, Hiroshi SHIIGI, Masaharu NAKAYAMA and Kotaro OGURA
Department of Applied Chemistry, Yamaguchi University
Tokiwadai, Ube 755-0031, Japan

Soluble polyaniline (PAn) was prepared by the chemical polymerization of aniline with ammonium peroxydisulfate in p-toluene sulphonic acid aqueous solution. The electrical conductivity of the PAn / PVA composite film was linearly related with the atmospheric humidity, extending from 3.5×10^-5 to 0.2 S cm^-1 upon the change in humidity from 0 to 100%. The measurements performed in both moistening and desiccating processes accompanied no any hysteresis. The effect of coexisting gases on the humidity-dependence of the composite film was here investigated to disclose the working scheme.

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28.
プラズマ有機薄膜を被覆した QCMセンサによる香り分子の微量検出および識別

河西奈保子、杉本岩雄、中村雅之

NTT入出力システム研究所

DETECTION AND DISCRIMINATION OF TRACE AMOUNT OF ODORANTS USING PLASMA-ORGANIC-FILM-COATED QCM SENSORS

Nahoko Kasai, Iwao Sugimoto and Masayuki Nakamura

NTT Integrated Information & Energy Systems Laboratories
3-9-11 Midori-cho, Musashino-shi, Tokyo 180-0012, Japan

We conducted odorant-recognition experiments for the major single-odor substances in various types of foods and flowers using a gas-sensing system consisting of a sensor array of quartz crystal microbalances (QCMs) and a pattern-recognition technique. The sensing devices were fabricated by radio-frequency sputtering of amino acids or polymers onto QCM. Most of the tested odorants could be detected at concentrations lower than 0.1 ppm.
By using principal component analysis based on the amount of odorants sorbed for 180 minutes and adsorption time constant, these odorants could be discriminated satisfactorily. These results indicate this system is highly reliable in sensing and discriminating trace amount of odorants.

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29.
Con A・酵素累積膜を用いた酵素センサー

小林由佳、安斉順一

東北大薬

BIOSENSORS BASED ON Con A/ENZYME MULTILAYER-MODIFIED ELECTRODES

Yuka KOBAYASHI and Jun-ichi ANZAI

Faculty of Pharmaceutical Sciences, Tohoku University
Aobayama, Sendai 980-8578, Japan

Enzyme multilayer films were prepared on the surface of a quartz slide and a platinum electrode by depositing concanavalin A (Con A) and mannose-labelled glucose oxidase (GOx) alternately. The formation behavior of the layer-by-layer structure was studied by quartz-crystal microbalance , UV spectrophotometry, and electrochemistry. The results suggested the formation of enzyme multilayers in various concentration of Con A and GOx solutions. The size of output current of the glucose sensors depended linearly on the number of GOx layers. The response to glucose decreased gradually down to ca. 70% activity of the original value after a month.

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30.
耐熱性酵素を用いた各種 ISFET型糖類センサの構築と特性

青木一仁、石丸雄大、飯田武揚

埼玉大学工学部

ISFET-TYPE SACCHARIDE SENSORS USING THERMOPHILIC ENZYMES

Kazuhito AOKI, Yoshihiro ISHIMARU and Takeaki IIDA

Department of Functional Materials Science, Faculty of Engineering, Saitama University
255 Shimo-okubo, Urawa-shi, Saitama-ken 338, Japan

An ion sensitive field effect transistor (ISFET) glucose sensor, using thermophilic glucokinase (GK) from Bacillus stearothermophilus or thermophilic glucose dehydrogenase (GDH) from Thermoplasma acidophilum, immobilized by BSA and glutaraldehyde, was able to determine the D-glucose concentration.
The glucose sensor using thermophilic GK was applied to the sucrose sensor using thermostable invertase from Candida utilis and applied to the maltose sonsor using alpha-D-glucosidase from Bacillus stearothermophilus.
Each saccharide sensor was able to determine each saccharide under the conditions from room temperature to 50 or 60 degrees C.

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31.
ポリアニリンによる固定化酵素を利用した人工膵臓用グルコースセンサ

池田章一郎、上林貴洋、得野順一、工藤比戸美、伊藤勝基^*、高木弘^*

名工大・名大医^*

GLUCOSE SENSER FOR ARTIFICIAL PANCREAS USING IMMOBILIZED ENZYME WITH POLYANILINE

Shoichiro IKEDA, Takahiro KAMIBAYASHI, Junichi TOKUNO, Hitomi KUDO, Katsuki ITO^* and Hiroshi TAKAGI^*

Department of Applied Chemistry, Nagoya Institute of Technology
Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
^*Department of 2nd Surgery, School of Medicine, Nagoya University
Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan

Several types of implantable glucose sensors for artificial pancreas have been developed by authors. To improve the fabrication process of the sensors, electropolymerized membranes such as polyaniline have been employed to immobilize enzyme and restrict the permeability of glucose. Pt or Ti plates or wires were used as the base electrodes. From the time dependence of the activity of the immobilized enzyme, GOD, the activity lasted more than 1 month by Nafion and/or polypyrrole or polyaniline coating. The prototype sensor of Pt wire responded up to 500 mg/dl glucose in saline as ether an oxygen-type or hydrogen peroxide-type glucose sensor.

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32.
生体適合性を有するポリピロールを包括材料に用いた酵素固定電極の作製およびそのセンサ特性

安澤幹人、松木崇、三井光、椚　章、仲矢忠雄_*

徳島大工・阪市大工_*

PROPERTIES OF GLUCOSE SENSORS BASED ON THE IMMOBILIZATION OF GLUCOSE OXIDASE IN HEMOCOMPATIBLE POLYPYRROLE FILM

Mikito YASUZAWA, Takashi MATSUKI, Hikari MITSUI, Akira KUNUGI and Tadao NAKAYA

Department of Chemical Science and Technology, Faculty of Engineering, The University of Tokushima
2-1 Minamijosanjima, Tokushima 770-8506, Japan

New hemocompatible glucose sensors were prepared by electropolymerization of pyrrole derivatives having phosphatidylcholine, 5-(1-pyrrolyl)pentyl-2-(trimethylammonium) ethyl phosphate, in the presence of glucose oxidase (GOD). The introduction of Nafion or poly(o-phenylenediamine) (PPD) membrane to the GOD-immobilized electrode as the inner membrane not only to eliminate the influence of ascorbic acid on the sensor response but were also effective to increase the electrode stability. The electrode containing PPD inner membrane was shown to be relatively constant for more than 200 days or three times as long as the electrode without the inner membrane.

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33.
ポリウレタンを包括材料に用いた酵素センサの開発

安澤幹人, 長谷川美帆, 椚　章, 仲矢忠雄^*

徳島大工・阪市大工^*

GLUCOSE SENSORS BASED ON GLUCOSE OXIDASE IMMOBILIZED IN POLYURETHANE FILMS

Mikito YASUZAWA, Miho HASEGAWA, Akira KUNUGI and Tadao NAKAYA

Department of Chemical Science and Technology, Faculty of Engineering, The University of Tokushima
2-1 Minamijosanjima, Tokushima 770-8506, Japan

A novel glucose sensor based on glucose oxidase (GOD) immobilized in hemocompatible polyurethane film was prepared and the glucose sensor properties were investigated. The sensitivity of the electrode prepared with porous polyurethane film was three times as high as that with nonporous polyurethane film. The relationship between the glucose concentration and the response current was found to be linear up to 7.0 mM.
The response current was relatively constant for 60 days, after an initial change of signal over the first few days.

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34.
アニオン性導電性高分子を用いたペルオキシダーゼ電極

立間　徹、小川高史、小山　昇

東京農工大工

PEROXIDASE ELECTRODES WITH AN ANIONIC CONDUCTING POLYMER

Tetsu TATSUMA, Takashi OGAWA and Noboru OYAMA

Department of Applied Chemistry, Faculty of Technology, Tokyo University of Agriculture and Technology
Koganei, Tokyo 184, Japan

Peroxidase electrodes are prepared with an anionic conducting polymer, poly(2-methoxyaniline-5-sulfonic acid) (PMAS). A tin oxide electrode is coated with PMAS, which is insolubilized by using a polycation, poly(L-lysine) (PLL), and peroxidase is entrapped in the composite coating. Thus obtained peroxidase electrode amperometrically responds to hydrogen peroxide at potentials between +0.2 and -0.2 V vs. Ag/AgCl, even at neutral pH. It is verified that catalytic activity of peroxidase and electrochemical activity or conductivity of PMAS are responsible for the response.

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35.
電解重合高分子修飾電極による新規グルコースセンサー

孫　立賢、除　芬、岡田　達弘

物質工学工業技術研究所

The Development of Amperometric Biosensor for Glucose Based on Electropolymerized Salcomine and o-Phenylenediamine as well as Nafion

Li-Xian Sun, Fen Xu and Tatsuhiro Okada

National Institute of Materials and Chemical Research
1-1 Higashi, Tsukuba, Ibaraki 305, Japan

In this work, a new amperometric glucose sensor based on pyrolytic graphite (PG) modified with electropolymerized N,N'-Bis(salicylidene) ethylenediaminocobalt (Ⅱ), (i.e., Salcomine), electropolymerized o-Phenylenediamine (PPD), glucose oxidase (GOD), Nafion (perfluorosulfonic acid ionomer) and PPD sequentially is described. The response characteristics of glucose sensors were monitored in a electrochemical cell composed of prepared enzyme electrode (i.e., working electrode), a SCE reference electrode and a platinum auxiliary electrode in the presence of saturated oxygen at -0.1 V. The compositions of membranes of glucose sensors were compared and optimized by chemometrics approaches. Results obtained show that sensor containing PG/Salcomine/PPD/GOD/Nafion/PPD with the potimal memgrane composition in this study has good characteristics such as effective refection of interference, relatively wide linear range and long-term stabillity.

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36.
親油性メディエーターを用いたカーボンペースト／アルコールデヒドロゲナーゼ電極の作製

姚　晴，矢吹聡一，水谷文雄

生命工学工業技術研究所

Preparation of a Carbon Paste/Alcohol Dehydrogenase Electrode based on Oil-Soluble Mediator

Qing YAO, Soichi YABUKI and Fumio MIZUTANI

National Institute of Bioscience and Human-Technology
Higashi, Tsukuba, Ibaraki 305-8566, Japan

Carbon paste(CP)/enzyme electrode was prepared from carbon paste incorporating polyethylene glycol-modified alcohol dehydrogenase (PEG-ADH), NAD+ and oil-soluble mediator, 7-dimethylamino-2-methyl-3-β -naphthamido-phenothiazinium chloride (3-NTB). The usage of oil-soluble mediator lengthened the long-term stability of the electrode: after 18 days, current response to 1 mM glucose using the electrode was reduced to be 80 % of the initial value. For a CP/enzyme electrode based on a water-soluble mediator, toluidine blue (TB), current response was reduced to be 50 % after 3 days. The enzyme electrode was used for the determination of ethanol concentration in the alcoholic drinks. The results obtained by the proposed method are in fairly good agreement with that obtained by F-kit (Boehringer Mannheim). The electrode could be used an alcohol biosensor.

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37.
電極／ポリイオンコンプレックス膜／NADH酸化酵素膜の構成のNADHセンサ

水谷文雄，佐藤　縁，平田芳樹，矢吹聡一

生命工学工業技術研究所

AMPEROMETRIC NADH-SENSING ELECTRODE BASED ON NADH OXIDASE/POLYION COMPLEX-BILAYER MEMBRANE

Fumio MIZUTANI, Yukari SATO, Yoshiki HIRATA and Soichi YABUKI

National Institute of Bioscience and Human-Technology
1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan

An amperometric NADH-sensing electrode was prepared by immobilizing NADH oxidase on a polyion complex layer-coated electrode as follows. First, a monolayer of 3-mercaptopropionic acid was made on the surface of a gold electrode by immersing it in an ethanol solution containing the modifier. Aqueous solutions of poly-L-lysine and poly(4-styrenesulfonate) were successively placed on the electrode surface and allowed to dry. Finally, an NADH oxidase layer was formed on the poly-L-lysine/poly(4-styrenesulfonate)-complex layer by crosslinking the enzyme by the addition of a glutaraldehyde solution. The use of thin bilayer system with the inner polyion complex layer, which showed permselectivity based on the solute size with the molecular cut-off of ac. 100, brought about high performance characteristics to the NADH-sensing electrode. The electrode showed high sensitivity (detection limit, 50 nM), rapid response (100% response time, <5 s) and low interferential response (e.g., the ratio of response for L-ascorbic acid to the same concentration of NADH, 0.1).

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t2.
生体機能電極界面の構築とセンシング

谷口　功

熊本大工

DESIGN OF FUNCTIONAL SURFACES OF ELECTRODES FOR BIOELECTROCHEMICAL SENSING

Isao TANIGUCHI

Department of Applied Chemistry and Biochemistry,　Faculty of Engineering, Kumamoto University
Kurokaki, Kumamoto 860-8555, Japan

Preparation of suitable interfaces, at which rapid electron-transfer reactions and recognition of biological molecules can take place, has been discussed for fundamental studies of biological functions and for application such surfaces to design various electrochemical sensors. In the present study, to understand surface functions at the molecular level, atomically flat and well-defined ordered surfaces modified with biofunctional molecules have been prepared and characterized for such cases as cytochrome c electrochemistry at electron-transfer promoter modified electrodes and STM images of the modified electrode surfaces, fabrication of functional surfaces with thiols and electrochemical sensing of the functionalized surfaces, and electrochemistry of artificially-designed proteins.

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38.
アンモニアおよびホルムアルデヒドに対する観葉植物の応答特性

小野寺武，広林茂樹，木村春彦，大薮多可志^*

金沢大工，金沢経済大経済^*

RESPONSES OF FOLIAGE PLANTS TO AMMONIA AND FORMALDEHYDE GASES

Takeshi ONODERA, Shigeki HIROBAYASHI, Haruhiko KIMURA and Takashi OYABU^*

Kanazawa University
Kodatsuno, Kanazawa 920-8667, Japan
^*Kanazawa College of Economics
Gosho-machi, Kanazawa 920-0813, Japan

A plant has an ability to adapt to various environments. In other words, the plant can feel sensitively to environmental changes. In this study, responses of the plants to indoor air pollutant are examined. They are foliage plants. The plant is put in a chamber which is about 64.8 liter and the response characteristics are measured. An electroencephalograph is connected with a pair of electrodes of electrocardiogram pasted on a leaf of the foliage plant, and a bioelectric potential can be measured. An electric stimulator is connected with another pair of electrodes which are pasted on another leaf. An electric stimulus is given to the leaf. Ammonia and formaldehyde, gases which are air pollutants, are injected into the chamber respectively. At this time, a response change for the electric stimulus is examined. Response characteristics of the plants to ammonia gas havea sudden rising and they also have a big change. The responses of the plants to formaldehyde gas are, however, differed in every plants.

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39.
ラジカルスカベンジャーを用いた in situ NOセンサの構築

亀井謙一郎、春山哲也、柳田保子、小畠英理、相澤益男

東工大・生命理工

CONSTRUCTION OF IN SITU NO SENSOR WITH RADICAL SCAVENGER

Ken-ichiro KAMEI, Tetsuya HARUYAMA, Yasuko YANAGIDA, Eiry KOBATAKE and Masuo AIZAWA

Department of Bioengineering, Faculty of Bioscience and Biotechnology Tokyo Institute of Technology

Electrochemical NO measurment system with NO specific radical scavenger PTIO have been developed. To develop an in situ NO sensing system for primarily biological use, sensorlial behaver of PTIO deposited electorde was investigated. PTIO was deposited on a Pt electrode surface with Tefron powder to form a hydrophobic layer. The potential of the C-PTIO immobilized electrode was set at 0.75 V vs. Ag/AgCl The anodic current increased with responding to NO. The response was not interfered by NO^2-, most probably due to negatively charged layer of PTIO and Nafion. The PTIO immobilized electrode could determine NO concentration range from 0.2μM to 3μM in aqueous solution.

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40.
微生物発光を利用した環境モニタリングシステムの開発

村橋瑞穂，北川　圭^**，松井暢人，宮本正規^*，阪口利文^**，村上裕二^**，横山憲二^**，民谷栄一^**

（株）イシメックス・石川県工業試験場^*・北陸先端科技大^**

DEVELOPMENT OF THE ENVIROMENTAL MONITORING SYSTEM USING LUMINESCENT BACTERIA

Mizuho MURAHASHI, Kei KITAGAWA, Nobuhito MATSUI, Masaki MIYAMOTO,　Toshifumi SAKAGUCHI, Yuji MURAKAMI, Kenji YOKOYAMA and Eiichi TAMIYA

Ishimex Co.,Ltd.
Matto, Ishikawa 924-0051, Japan

We have developed a new rapid BOD monitoring system using luminescent bacteria,　Photobacterium phosphoreum. The luminescent intensity was measured with photodiode. The luminescent values were correlated with concentration of organic compounds. The increased luminescent intensity was in a linear relationship to BOD concentration of standard solution. In the presence of toxic substances such as heavy metal ions, organic reagents and surfactant, this method was not interfered with sub-ppm level of them. Therefore this monitoring system can be applied satisfactorily to the determination of BOD in riverwater and waste water.

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41.
バイオセンサとイオンセンサのフュージョンシステムによる浸透圧の評価

橘亜樹^*、外山滋、吉田泰彦^*、碇山義人

国立リハビリ研、東洋大工^*

FUSED SENSOR SYSTEM FOR THE MEASUREMENT OF OSMOTIC PRESSURE

Aki TACHIBANA^*, Shigeru TOYAMA, Yasuhiko YOSHIDA^* and Yoshihito IKARIYAMA

National Rehabilitation Center for the Disabled
4-1 Namiki, Tokorozawa 359, Japan
^*Department of Applied Chemistry, Faculty of Engineering, Toyo University
2100 Kujirai, Kawagoe 350, Japan

We demonstrate here a fused sensor system to obtain physiological information by assembling three sensors. Clinically, osmotic pressure can be expressed by the following equation.
Π≒1.86×Na⁺(mM) + Glucose (mM) + Urea (mM)
This suggests that one can determine osmotic pressure by fusing three sensor elements. Among the sensors, urea sensor was fabricated by immobilizing urease, glutamate dehydrogenase, glutamate oxidase at platinum black electrode, so that urea can be measured at 0.5 V vs. Ag/AgCl. Here the characteristics of three sensor elements are described to fabricate a fused sensor device.

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42.
微小液絡型銀／塩化銀参照電極と3電極系の１チップ上への集積化

鈴木博章、平川大志、佐々木聰^*、軽部征夫^*

筑波大物質工・東大先端研^*

MICROMACHINED LIQUID-JUNCTION Ag/AgCl REFERENCE ELECTRODE AND INTEGRATION OF THE THREE ELECTRODE SYSTEM

Hiroaki SUZUKI, Taishi HIRAKAWA, Satoshi SASAKI^* and Isao KARUBE^*

Institute of Materials Science, University of Tsukuba
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
^* RCAST, The University of Tokyo
4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan

A miniature liquid-junction Ag/AgCl reference electrode was fabricated using micromachining techniques. The Ag/AgCl element was formed by covering the surface of a silver pattern with a hydrophobic negative photoresist layer and growing AgCl from the edges of the pattern. The container and the liquid junction were formed on a silicon substrate using anisotropic etching. By closing the end of the junction with cellulose acetate, potential stability within ± 1 mV was maintained for approximately 4 h. The miniature reference electrode was applied to pH sensing. A good Nernstian response was observed with a slope of -58.1 mV/pH. By employing this miniature reference electrode, the three electrode system was integrated on a chip. The reference electrode was formed on one side of a glass substrate and a working (Pt) and a counter (Pt) electrodes were formed on the other side. In order to test its applicability, it was used to fabricate a miniature glucose sensor.

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43.
SPV法を用いた新しいコリンエステラーゼ固定化バイオセンサ

O.V. Fedosseeva, 内田秀和、勝部昭明、石丸雄大、飯田武揚

埼玉大工

Novel Type Biosensor Based on the Cholinesterase Multi-layer Electrode Using Differential Surface Photovaltage Technique

O.V.Fedosseeva, H.Uchida, T.Katsube, Y.Ishimaru and T.Iida

Faculty of Engineering, Saitama University
255 Shimo-okubo, Urawa-shi, Saitama 338-8570, Japan

Acetylcholinesterase (AChE) has attracted much attention because of its usefulness as a sensitive indicator of a normal nerve-muscle interaction. Acetylcholinesterase is a specific cholinesterase, hydrolyzing predominantly choline esters. This report deals with a new solid-state microbiosensor using a Surface Photovoltage (SPV) technique combined with a developed multi-layer method to immobilize cholinesterase on the semiconductor surface. Two types of cholinesterase were utilized, acetylcholinesterase and butyrylchlolinesterase, depending on the type of substrates. The surface of the n-type silicon wafer was treated by 3-(trimethoxysilyl) propylamine to obtain a hydrophobic surface on which the glutaraldehyde-crosslinked cholinesterase layer was deposited in the saline containing 15 mM NaCl and 1mM phosphate buffer pH 7.0 . The new measurement methods of Surface Photo Voltage (SPV) technique and the differential SPV were applied to the novel type biosensor based on immobilized cholinesterase. The photocurrents as a function of bias voltage applied between Si substrate and the reference electrode, were measured by focusing the light beam at the enzyme immobilized position. The time response curves for the photocurrent of the cholinesterase sensor, after addition of butyrylthiocholine iodide as a substrate of cholinesterase, decreased with the increase in the concentration of butyrylthiocholine iodide. These results indicate that the concentrations of substrates for cholinesterase are able to be determined by the cholinesterase immobilized sensor using SPV techniques. The effect of an inhibitor, physostigmine, on the photocurrent was also studied.

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44.
表面プラズモン共鳴現象を利用した化学センサ

南戸秀仁、羽原正秋、堂上長則、向井達哉、草野　英二、金原　粲、筒口善央^*

金沢工業大学高度材料研究開発センター、石川県工試^*

CHEMICAL SENSORS UTILIZING THE SURFACE PLASMON RESONANCE

Hidenito NANTO, Masaaki HABARA, Naganori DOGAMI, Tatsuya MUKAI, Eiji KUSANO, Akira KINBARA, Yoshio DOGUCHI^*

Advanced Materials Science Research&Development Center, Kanazawa Institute of Technology
^*Industrial Research Institute of Ishikawa

A chemical sensor based on the surface plasmon resonance(SPR) has various advantages in requirement of recent analysis technics. By applying the feature of SPR sensor, we studied product and process control in brewing process of Japanese Sake. The resultant SPR reflection spectrum changes in refractive indices of the sensed media. The experimental results show that a SPR-based optical sensor is expected to develop an application of real-time sensing system in both product and process control.

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45.
分子積層法による表面プラズモン共鳴（SPR）の信号増幅

西村知晃、一二三恵美、清水浩輔、宇田泰三

広島県立大生物資源

ENHANCEMENT OF THE SPR RESPONSE BY THE METHOD OF MOLECULAR ACCUMULATION

Tomoaki NISHIMURA, Emi HIFUMI, Kousuke SHIMIZU and Taizo UDA

School of Biosciences, Hiroshima Prefectural University
Shoubara-shi, Hiroshima 727-0023, Japan

We have already reported the sensing of antibodies for human immunodeficiency virus (HIV) using surface plasmon resonance (SPR). In addition, we could suppress the non-specific reaction caused by the effect of the ingredients of serum by employing heat treatment (56℃, 30 min) of the serum. Nonetheless, some improvements for the SPR must be attained to use it as a general biosensor tool. One of them is a high sensitive detection, which is a substantial subject in SPR sensor. Here, we tried to enhance the SPR response by accumulating the second and third antibodies on the first antibody, and we could enhance the SPR response by about 10 times.

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46.
SPR免疫センサ構築のための抗体固定化法の検討と集積化の試み

鈴木正康、森　悠丞

九州工大情報工

INVESTIGATION OF ANTIBODY IMMOBILIZATION METHODS FOR SPR IMMUNOSENSORS AND INTEGRATION OF SPR IMMUNOSENSORS

Masayasu SUZUKI and Yuusuke MORI

Department of Biochemical Engineering and Science, Faculty of Computer Science and Systems Enginnering, Kyushu institute of Technology
Iizuka-shi, Fukuoka 820-8502, Japan

The surface plasmon resonance ( SPR ) sensor is expected as a real-time immunosensor. In most of the SPR immunosensors, antibodies were immobilized onto the sensor chip via polymer matrices such as a dextran. In this study, seven immobilization methods which use no such polymer matrices. Among the seven methods, the two methods, (1) mercaptide formation between Fab' thiol group and the gold thin layer, and (2) crosslink formation between the bound IgG and protein G, showed the largest responses and the best reproducibility. By using the IgG-protein G crosslinking method, human IgM sensor and human IgA sensor were integrated onto the same SPR sensor chip. The integrated sensor showed responses to human IgM and human IgA independently.

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47.
金薄膜表面高分子層の最適設計と SPRセンサの高感度化

東海林崇^*、外山滋、吉田泰彦^*、碇山義人

国立リハビリ研、東洋大工^*

DESIGN OF POLYMER MATRIX FOR THE SENSITIZATION OF SPR-BASED IMMUNOSENSOR

Atsumu SHOJI^*, Shigeru TOYAMA,Yasuhiko YOSHIDA^* and Yoshihito IKARIYAMA

Research Institute, National Rehabilitation Center for the Disabled
4-1 Namiki, Tokorozawa 359-0042, Japan
^*Department of Applied Chemistry, Faculty of Engineering, Toyo University
2100 Kujirai, Kawagoe, Saitama 350-0815, Japan

Realtime and nonlabelled sensing based on antigen-antibody reaction has been investigated by a surface plasmon resonance(SPR)-based optical biosensor. The sensor detects the change in the refractive index of the metal film surface upon injection of antigen / antibody. Here, the characteristics of the sensor in immobilized format of antigen on gold surface are reported; immobilization of antigen / antibody on gold surface was performed by covalent immobilization to mixed polymer of hydroxyethylstarch and dextran sulfate. Upon the injection of antibody, the change in the SPR signal was the largest when DS was 42～44 percents of the polymer mixture. The detection limit of anti human albumin was less than μg/ml level.

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