Vol. 20, Supplement A (2004)

Abstracts

SPRニオイセンサの作成とその応答特性の評価

金沢工業大学、金沢工業大学高度材料科学研究開発センター

南戸秀仁、北出康人、久保田直義、竹井義法

Development of Odor sensor using surface plasmon resonance phenomenon and evaluation of sensing characteristics

H.Nanto Y.Kitade N.Kubota Y.Takei

Advanced Materials Science R&D Center, Kanazawa Institute of Technology,
3-1 Yatsukaho, Mattou, Ishikawa 924-0838, JAPAN

An Odor sensor based on the surface plasmon resonance (SPR) phenomenon has been developed to detect harmful gases such as ammonia and amine gases. The sensor element was prepared by means of depositing the molecular recognition membrane on a substrate coated with gold thin film using plasma chemical vapor deposition (CVD) method. It is found that the SPR sensor with acrylic acid membrane exhibited an excellent selectivity and high sensitivity for ammonia and amine gases.

IER法を利用したVOCセンサの開発

（有）オー・エス・ピー

○山本　弘信、山口　恭子

VOC SENSOR BASED ON AN INTERFERENECE ENHANCED REFLECTION TECHNOLOGY

Hironobu YAMAMOTO, Kyoko YAMAGUCHI

O.S.P. Inc.
3F Yamasho Bld. 2-14 Higashi-Mitsuki, Sayama-shi, Saitama, 350-1302 Japan

A volatile organic compounds (VOCs) sensor was developed based on an interference enhanced reflection technology. Sensor chips prepared from a polymeric thin film coated on a Si substrate were utilized for the detection of petrochemical hydrocarbons such as benzene and toluene, and chlorinated hydrocarbons such as trichloroethylene and tetrachloromethane down to the ppm order. A handy type sensor and a process monitor are applicable to simple, quick, and low-cost on-site survey and/or monitoring of air/water/soil contaminations.

エッチング方式による分布型光ファイバ水素センサの試作・評価

横浜国大工、東大先端研、東大院工学系研究科、宇宙航空研究開発機構

○住田慎太郎、岡崎慎司、石井孝正、朝倉祝治、中川英元、村山英晶、紙田　徹、長谷川卓也

EVALUATION OF A FIBER-OPTIC GAS SENSOR PREPARED BY ETHING METHOD FOR DISTRIBUTED HYDROGEN DETERMINATION

Shintaro SUMIDA, Shinji OKAZAKI, Takamasa ISHII, Shukuji ASAKURA, Hidemoto NAKAGAWA, Hideaki MURAYAMA, Tooru KAMITA, Takuya HASEGAWA

Graduate School of Engineering, Yokohama National University
Tokiwadai 79-5, Hodogayaku, Yokohama 240-8501, Japan

A fiber-optic hydrogen gas sensor using platinum-supported tungsten trioxide (Pt/WO₃) was characterized. This sensor utilizes the absorption of the evanescent field interaction in the clad of Pt/WO₃ thin film which was prepared by sol-gel method, coated on a silica core. This type of the sensor has the potential for distributed measurement to detect the location of hydrogen leakage points. When 15cm-length of the fiber sensor was examined, considerable attenuation of the backscatter light level was observed in OTDR traces. The light loss at the sensing portion was 6.3dB. On the other hand, sensitivity to hydrogen gas was proportional to sensing fiber length. In order to improve this fiber attenuation property, etching method for removing silica cladding was introduced in sensor fabrication process and optimized.

Br^-/IO₃^-電解質を用いた酸性ガスセンサの実用性評価

理研計器（株）

○今屋浩志、岡村 圭、上杉慎治、打越祥一、石地 徹

ACIDIC GAS DETECTION BY ELECTROCHMEICAL SENSOR USING Br^-/IO₃^- ELECTROLYTIC SOLUTION

Hiroshi IMAYA, Kei OKAMURA, Shinji UESUGI, Syoichi UCHIKOSHI and Toru ISHIJI

Riken Keiki Co., Ltd.
2-7-6 Azusawa Itabashi-ku, Tokyo 174-8744

Amperometric sensors for the detection of acidic gases, such as hydrogen fluoride(HF) and hydrogen chloride(HCl), have been studied. This detection method of acidic gas is based on the electrode reaction properties of halogen liberated from halide ion / halate ion solution by addition of hydrogen ion. The detectable gases on the acidic gas sensor were depended on the composition of halide/halate ion for the electrolytes. In this study, we have investigated the amperometric ClF₃ gas sensor by using Br^-/IO₃^- electrolytic solution. This sensor showed a good sensitivity for the ClF₃ gas, but low sensitivity for the O₃, which was existed as an interference gas in the air. This characteristic of the sensor is useful for practical usage.

カーボン-フッ素樹脂混合膜を用いた電気化学NO₂センサ

理研計器^*、山梨大学^**

○水谷好孝^*,**、松田裕之^*、石地徹^*、古屋長一^**

AMPEROMETRIC NO₂ SENSOR BY USE OF CARBON-FLUOROCARBON MEMBRANE

Yoshitaka MIZUTANI^*,**, Hiroyuki MATSUDA^*, Toru ISHIJI^* and Nagakazu FURUYA^**

^*Riken Keiki Co., Ltd. 2-7-6 Azusawa Itabashi-ku, Tokyo 174-8744
^** Faculty of Engineering, Yamanashi University, 4-3-11 Takeda Koufu-shi, Yamanashi 400-8511

Amperometric gas sensor for the detection of NO₂ was developed by use of a novel gas permeable electrode. Although low concentration of NO₂ could be detected by use of a conventional electrochemical sensor using a porous PTFE membrane, it was influenced a little for coexisting gases such as ozone. So we tried to improve the selectivity of the sensor by using a novel type of gas diffusion membrane consisting of carbon powder and poly-fluorocarbon. The sensor shows a good sensitivity for low concentration of NO₂ gas but no response to ozone.

硝酸リチウムを添加した希土類酸化物を検出極として用いた固体電解質型NOガスセンサ

阪大院工

○田村真治, 長谷川功, 今中信人

SOLID ELECTROLYTE TYPE NO GAS SENSOR WITH LINO₃ DOPED RARE EARTH OXIDE AS AN AUXILIARY ELECTRODE

Shinji TAMURA, Isao HASEGAWA, Nobuhito IMANAKA

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

A new solid electrolyte type nitrogen monoxide (NO) gas sensor was fabricated by using trivalent Al³⁺ cation and divalent O^2- anion conducting solid electrolytes with the rare earth oxide based auxiliary electrode. Not only the present NO gas sensor shows such a practical performance of a rapid, stable, continuous, and reproducible response but also the linear relationship between the sensor output and the logarithm of the NO concentration was obtained in the gas concentration range from 200 to 2000 ppm,. The n value (1.03) calculated from the EMF - log(PNO) relationship was in excellent agreement with the theoretical one (n=1.00) for the sensor with 0.325(Gd_0.9La_0.1)₂O₃-0.35LiNO₃ as the auxiliary electrode at such a low temperature of 250℃.

酸化ニッケルを検知極とした混成電位型ジルコニアNOｘセンサの高温作動特性

九大産学連携センター ¹　、九大院総理工 ²

○王 健 ¹、中藤 充伸 ²、三浦 則雄 ¹

MIXED-POTENTIAL-TYPE ZIRCONIA SENSOR USING NICKEL OXIDE SENSING- ELECTRODE FOR DETECTION OF NOx AT HIGH TEMPERATURES

Jian WANG ¹, Mitsunobu NAKATOU ², Norio MIURA ¹

¹ Art, Science and Technology Center for Cooperative Research, Kyushu University,
Kasuga-shi, Fukuoka 816-8580
² Interdisciplinary Graduate School of Engineering Sciences, Kyushu University,
Kasuga-shi, Fukuoka 816-8580, Japan

A mixed-potential-type NOx sensor was tested with NiO attached sensing-electrode (SE) in the temperature range of 800 - 900°C aiming for high-temperature emission control. With improvement of on-board exhaust-monitoring, it is necessary to search a sensing material of NOx sensor, which can provide a good sensitivity to detect NOx at high temperatures. Among thirteen single-oxides tested, NiO was found to be most sensitive and responsive to NO₂ even at 850°C. The sensor attached with the NiO-SE gave better sensing performances (higher sensitivity and faster response) in the wet sample gas, compared with those observed in the dry gas condition. The results obtained could make a valuable contribution to the improvement of the mixed-potential-type NOx sensors operating at high temperatures for monitoring exhaust gas on-board.

混成電位型およびインピーダンス応答型NOxセンサの応答特性に対する酸化物検知極の膜厚の影響

九大院総理工¹、 九大産学連携センター ²

○古閑 達也 ¹、 中藤 充伸 ¹、 三浦 則雄 ²

INFLUENCE OF THICKNESS OF OXIDE ELECTRODE ON SENSING PERFORMANCES OF MIXED-POTENTIAL-TYPE AND IMPEDANCEMETRIC NOx SENSORS

Tatsuya KOGA ¹，Mitsunobu NAKATOU ¹，Norio MIURA ²

¹ Interdisciplinary Graduate School of Engineering Sciences, Kyushu University,
Kasuga-shi, Fukuoka 816-8580
² Art, Science and Technology Center for Cooperative Research, Kyushu University,
Kasuga-shi, Fukuoka 816-8580

The correlation between the thickness of the oxide sensing-electrode (SE) and the sensing performances of both mixed-potential-type and impedancemetric NOx sensors was investigated at 700°C for electrodes with controlled thickness from about 5 μm to about 40 μm. The sensing characteristics were investigated for NOx concentrations from 50 ppm up to 400 ppm for both types of sensors. It was shown that the impedancemetric NOx sensor, employing ZnCr₂O₄ as the SE, provided almost equal sensitivity to both NO and NO₂ only when the thickness of SE was about 40 μm. It is speculated that, by using thick SE, the composition of NOx may reach equilibrium at the SE/YSZ interface. In contrast, the mixed-potential-type NOx sensor performed best when the thickness of SE was as small as about 5 μm. The sensing mechanisms of both types of sensors are discussed based on the results obtained.

高温での低濃度水蒸気の検出が可能な複素インピーダンス応答型ジルコニアセンサ

九大院総理工 ¹、 九大産学連携センター ²

○中藤 充伸 ¹、　三浦 則雄 ²

IMPEDANCEMETRIC ZIRCONIA-BASED SENSOR FOR DETECTING LOW WATER-VAPOR CONCENTRATION AT HIGH TEMPERATURE

Mitsunobu NAKATOU ¹ and Norio MIURA ²

¹ Interdisciplinary Graduate School of Engineering Sciences, Kyushu University,
Kasuga-shi, Fukuoka 816-8580, Japan
² Art, Science and Technology Center for Cooperative Research, Kyushu University,
Kasuga-shi, Fukuoka 816-8580, Japan

We have previously reported a new impedancemetric total-NOx sensor based on yttria-stabilized zirconia (YSZ) and a ZnCr₂O₄ sensing-electrode (SE) at 700°C. Here, we proposed a new-type water-vapor sensor using the same YSZ-based device that could measure the low water-vapor concentration at high temperature. Among the various single-oxide SEs tested, In₂O₃-SE gave the highest sensitivity to water vapor at 900°C. The sensitivity of the device was almost linear to the logarithm of water-vapor concentration in the wide range from about 100 ppm to about 30000 ppm. In addition, it was confirmed that the present sensor could detect various hydrogen-containing gases, such as H₂ and hydrocarbons, under dry condition at 900°C. It is speculated that the hydrogen-containing gases are oxidized completely to H₂O and CO₂ due to the high catalytic activity of In₂O₃ for gas-phase oxidation reaction at high temperature.

Nd-Si-Al-O系固体電解質の酸化物イオン伝導

愛媛大工

竹田尚貴、板垣吉晃、○青野宏通、定岡芳彦

OXIDE ION CONDUCTION FOR SOLID ELECTROLYTE OF Nd-Si-Al-O SYSTEM

Naoki TAKEDA, Yoshiteru ITAGAKI, Hiromichi AONO, and Yoshihiko SADAOKA

Department of Materials Science and Engineering, Ehime University,
Bunkyo-cho 3, Matsuyama-shi, Ehime 790-8577

The solid electrolyte for the Nd_9.33+x/3Si_6-xAl_xO₂₆ (0≦x≦2) system was prepared by the sintering at 1600 oC for 5 h. Although a Nd₂SiO₅ phase was contained as a second phase for low x region, the single phase was obtained for x=1.5. The conductivity was enhanced by an increase in x value and the highest value 1.0×10^-3 S・cm^-1 at 500℃ was obtained for x=1.5. The transfer number of O^2- ion in the electrolyte was unity even at low temperature for x=1.5 which was confirmed by O₂ gas concentration cell.

K-Al-Si-O系固体電解質のイオン伝導と炭酸ガスセンサへの応用

愛媛大工

伊東祐介、板垣吉晃、○青野宏通、定岡芳彦

IONIC CONDUCTIVITY AND ITS APPLICATION OF CO₂ GAS SENSOR FOR SOLID ELECTROLYTE OF K-Al-Si-O SYSTEM

Yusuke ITOH, Yoshiteru ITAGAKI, Hiromichi AONO, and Yoshihiko SADAOKA

Department of Materials Science and Engineering, Faculty of Engineering,
Ehime University, Matsuyama, 790-8577

The K-Al-Si-O system electrolyte was prepared and it was applied for an EMF type CO₂ gas sensor. The maximum conductivity was obtained for n=4 in the K₂O-Al₂O₃-nSiO₂ system. The drifts of EMF response were confirmed for CO₂ gas sensor using a combined electrolyte of K₂O-Al₂O₃-4SiO₂ and YSZ pellet with K₂CO₃ auxiliary phase. The possibility of the formation of some potassium silicates was confirmed by the reaction of K₂CO₃ and electrolyte.

NASICONを用いた室温作動型CO₂センサの参照極材料の検討

北九州高専、^*ＴＤＫ、^**九大院総理工　

小畑賢次、熊澤志津子^*、松嶋茂憲、島ノ江憲剛^**、山添　�f^**

EXPLORATION OF REFERENCE ELECTRODDE MATERIALS FOR NASICON-BASED CO₂ SENSOR OPARATIVE AT ROOM TEMPERATURE

Kenji OBATA, Sizuko KUMAZAWA^*, Shigenori MATSUSHIMA, Kengo SHIMANOE^** and Noboru YAMAZOE^{* *}

Kitakyushu National College of Technology, Materials Science and Chemical Enginnering,
5-20-1 Shii, Kokuraminami-ku, Kitakyushu-shi, Fukuoka 802-0985, Japan
^*R & D Center, TDK Corporation, Ichikawa-shi, Chiba 272-8558, Japan
^{* *} Department of Materials Science, Faculty of Engineering Sciences, Kyushu University,
Kasuga-shi, Fukuoka 816-8580, Japan

The NASICON (Na₃Zr₂Si₂PO₁₂)- based electrochemical device attached with a metal oxide (ITO) sensing electrode and a metal carbonate auxiliary phase (Li₂CO₃-BaCO₃) shows excellent CO₂ sensing capability at room temperature (30 °C) under humidity conditions. The long-term stability of this device is determined by its counter (or reference) electrode potential. In order to stabilize the counter or reference electrode potential of the device, it was investigated the applicability of Na_XCoO₂, Li_XCoO₂, Li₂TiO₃ to the reference electrode materials. Among these materials tested, Na_XCoO₂ was found to take thermal and/or chemical stabilities by means of XRD measurement. When Na_XCoO₂ was introduced the device for the solid reference electrode material, it exhibited excellent CO₂ sensing properties in the range of 300 - 3000ppm under humid conditions between 30 and 70 % at 30 °C.

Capacitive type gas sensors combining semiconductor and solid electrolyte

○ C. Zamani, K. Shimanoe^*, and N. Yamazoe^*

Interdisciplinary Graduate School of Engineering Sciences, Kyushu University
^*Faculty of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

A new capacitive type gas sensor for NO₂ was fabricated by depositing NaNO₂-based solid electrolyte layer together with an Au electrode over Insulator-Semiconductor. The resulting device exhibited ideal Metal-Insulator-Semiconductor (MIS) characteristics at 130-150 oC in air. It was found that in NO₂ -containing air, the voltage at constant capacitance shifts downward in a well-controlled manner as the NO₂ concentration is increased. The voltage necessary to keep the capacitance was found to decrease linearly with an increase in the logarithm of NO₂ concentration. In this presentation, the device preparation method and the sensing mechanism are described.

熱電式水素センサの小型化

(産総研)

　申 ウソク、邱　法斌、田嶌一樹、伊豆典哉、松原一郎、村山宣光

MICROFABRICATION OF THERMOELECTRIC HYDROGEN SENSOR

W. Shin, F. Qiu, K. Tajima, N, Izu, I, Matsubara, N. Murayama

Synergy Materials R. C., AIST
Nagoya, Aichi 463-8569 JAPAN

A thermoelectric hydrogen sensor was prepared with the combination of the thermoelectric effect of SiGe film and the Pt-catalyzed exothermic reaction of hydrogen oxidation. Amorphous SiGe film was deposited by RF-sputtering method and transparent glass substrate was used for the convenience of aligning different patterns in the preparation of the small-size hydrogen sensor. At the operation temperature of 100℃, the sensitivity to 3% H₂ is about 0.7 mV for the sensor with SiGe filmsintered at 500℃, and the detectable concentration is roughly in the range of 0.02-5%. With the sintering temperature elevated, the sensitivity was enhanced further. Microfabrication of the sensor using the anisotropic etching of Si substrate was also carried out and its performance was compared with the device with glass substrate.

酸化セリウム厚膜を有する抵抗型酸素センサの高速応答評価

(産総研)

　○伊豆典哉、申ウソク、松原一郎、村山宣光

EVALUATION FOR FAST RESPONSE PROPERTY OF RESISTIVE OXYGEN SENSORS USING CERIUM OXIDE THICK FILMS

Noriya IZU, Woosuck SHIN, Ichiro MATSUBARA, Norimitsu MURAYAMA

National Institute of Advanced Industrial Science and Technology (AIST), Nagoya, Aichi 463-8569 JAPAN

The response times t₉₀ and t_b were measured by jump method and dynamic method, respectively. The t_b for the oxygen sensor having about 100 nm grain size was 134 ms or less at 1173K. The value of t₉₀ for them was 20 and 1 ms in the case of the oxygen partial pressure change from high to low and from low to high, respectively. It was concluded that the kinetics of the sensor using cerium oxide with 100-300 nm grain size were controlled by diffusion.

SnO₂系センサにおけるベンゼンガスの応答挙動

長崎県窯業技術センター

○永石雅基

BENZENE GAS SENSING BEHAVIOR OF A SnO₂-BASED SENSOR

Masaki NAGAISHI

Ceramics Research Center of Nagasaki, hasami-cho 605-2, Nagasaki, 859-3726, Japan

The sensing properties to benzene gas have been investigated for pure SnO₂ and 0.2wt%Pt-SnO₂ sensors at temperatures of 200 - 600゜C. As a result, the sensitivity of pure SnO₂ sensor was increased with the increasing temperature, and a maximum sensitivity (S=1.9) was indicated at 500゜C. On the other hand, a maximum sensitivity (S=4.9) of 0.2wt%Pt- SnO₂ sensor was increased about three times in comparison with its of pure SnO₂ sensor, a maximum temperature was shift toward a low temperature at 100゜C.

Pd/陽極酸化TiO₂膜水素ガスセンサのガス検出特性に及ぼす前処理および湿度の影響

長崎大学工学部

○宮崎　洋、兵頭健生、清水康博、江頭　誠

INFLUENCE OF THE PRETREATMENT AND HUMIDITY ON THE H₂ GAS SENSING PROPERTIES OF Pd/ANODICALLY OXIDIZED TiO₂ FILM GAS SENSORS

Hiroshi MIYAZAKI, Takeo HYOUDOU, Yasuhiro SHIMIZU, and Makoto EGASHIRA

Department of Materials Science and Engineering, Faculty of Engineering,Nagasaki University
1-14 Bunkyo-machi, Nagasaki 852-8521, Japan

H₂ response properties of Pd/anodically oxidized TiO₂ film gas sensors have been investigated under different pretreatment and measurement conditions. The sensors exhibited fast and reversible response to H₂ at 250°C in air as well as N₂ atmosphere. However, H₂ response properties of the sensors both in air and N₂ were found to vary significantly with the pretreatment conditions: the pretreatment at 600°C for 1 h in N₂ resulted in deteriorated H₂ response, in comparison with the pretreatment at 600°C for 1 h in air. Among the conditions tested, the highest response to H₂ was achieved in N₂ after the pretreatment in air. When the sensor was pretreated in air, it showed reversible response to H₂ in N₂ even at room temperature. These results imply that the surface oxidation state of the Pd electrode affects the H₂ response. It was also revealed that H₂ response increased more or less with the presence of water vapor, especially in air, while the recovery deteriorated slightly.

SnO₂を用いたC₂H₄Oガスセンサにおける修飾効果

九大院総理工

○釘島裕洋、酒井　剛^*、島ノ江憲剛^*、山添　�f^*

SENSITIZATION OF SnO₂ GAS SENSOR FOR ETHYLENE OXIDE

Masahiro KUGISHIMA, Go SAKAI^*, Kengo SHIMANOE^* and Noboru YAMAZOE^*

Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan
^*Department of Materials Sciences, Faculty of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

A thick film device using neat SnO₂ was far from meeting the sensitivity to C₂H₄O required for the safety purpose. It was tried to enhance the C₂H₄O sensitivity by loading SnO₂ with foreign additives(e.g. La₂O₃, SrO and CaO). Among the additives, La₂O₃ proved itself to be a promising promoter for the sensitivity. The response and recovery rates, however, were found to be deteriorated with La₂O₃. The rates were restored considerably when the device was further added with Pd. Pd(0.5wt.%)-La₂O₃(0.5wt.%)-SnO₂ device thus prepared showed the sensitivity exceeding 4 to 1 ppm C₂H₄O and fairly good response rates under dry conditions at 250°C.

Co₃O₄で増感したSnO₂厚膜センサのCO検知特性

九大院総理工

○安部俊志、酒井　剛、島ノ江憲剛、山添　昇

CO Sensing Characteristic Using Co₃O₄-modified Thick Film SnO₂

S. Abe, G. Sakai^*, K. Shimanoe^*, N. Yamazoe^*

Interdisciplinary Graduate School of Engineering Sciences, Kyushu University
^*Faculty of Engineering Sciences, Kyushu Uviversity
Kasuga-shi, Fukuoka 816-8580, Japan

A series of Co₃O₄(0.5wt%)-SnO₂ composites were prepared from both oxide powders through mixing in a ball mill for various time spans. The resulting composites were applied to thick film type CO sensor by using screen-printing. It was found that the sensor response, defined as the ratio of electrical resistance in air to that in gas, was greatly promoted by increasing ball-milling time. The response went through a maximum as high as 1000 to 100ppm CO in air, at the ball-milling time of 6h. SEM observation revealed that the microstructure of the devices changed with the ball-milling time, becoming the most porous after the ball milling for 6h. For comparison, SnO₂ powder was impregnated with an aqueous solution of cobalt acetate and calcined at 600℃. The resulting thick film device was far less sensitive to CO than the above devices. The sensitivity was improved by some extent when the impregnated powder was ball milled, but it still remained modest even when optimized, being smaller than 100 to 100ppm CO in air. The reason for the difference in sensitivity between the ball-milling powder and the impregnated powder is under investigation.

低湿度下におけるSnO₂系ガスセンサのCO検知特性

九大院総理工、フィガロ技研(株)

有須田修一、酒井　剛^*、島ノ江憲剛^*、山添　�f^*、大戸亀久美^**

CARBON MONOXIDE SENSING PROPERTIES OF SnO₂ BASED GAS SENSOR UNDER LOW HUMID CONDITION

Syuichi ARISUDA, Go SAKAI, Kengo SHIMANOE, Noboru YAMAZOE and Kikumi OTO

Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University,
Kasuga-shi, Fukuoka 816-8580, Japan
^*Department of Materials Sciences, Faculty of Engineering Sciences, Kyushu University,
Kasuga-shi, Fukuoka 816-8580, Japan
^**Figaro Engineering Inc., 1-5-11 Senba-nishi, Mino, Osaka562-8505

Response of SnO₂-based sensors to CO under extreme conditions was investigated. It was found that PdO and V₂O₅-loaded SnO₂ device (thick film), after a reduction treatment in CO flow, showed reverse response to dilute CO (increase in resistance) under particular operating conditions , i.e., lower temperature below 325℃ , low humidity less than 100 Pa water vapor pressure. The reverse response tended to be more conspicuous as the CO concentration decreased and the coexistent O₂ partial pressure increased.
The reverse response changed to normal response when the device was calcined in air at 500℃. Similar reduction-induced reverse response to CO was also observed with Pd-loaded SnO₂ device, suggesting that the phenomena should be related with the oxidation state of SnO₂.

半導体ガスセンサのVOC選択性に及ぼすNO₂ガスの影響

愛媛大工

木村貴之、板垣吉晃、○青野宏通、定岡芳彦

INFLUENCE OF NO₂ GAS ON VOC SELECTIVITY FOR SEMICONDUCTOR-TYPE GAS SENSORS

Takayuki KIMURA, Yositeru ITAGAKI, Hiromichi AONO, Yosihiko SADAOKA

Department of Materials Science and Engineering, Faculty of Engineering,
Ehime University, Matsuyama, 790-8577

The conductance changes of n-type SnO₂ gas sensors (TGS2600, TGS2620, TGS2611, TGS2400), with VOCs and NO₂ in air were examined at various operating temperatures. By using at least two sensors operating at a different temperature, prediction of VOC gas became possible for low concentration region (0 ~ 1.5 ppm). Although the prediction of the contaminated levels with VOCs became difficult when NO₂ concentration was very high (10 ppm), it was possible for lower NO₂ gas concentration region.

CuO-In₂O₃薄膜センサの四塩化炭素に対する検知特性と触媒活性

立命館大理工、フィガロ技研^*

○福西淳也、玉置　純、河口智博^*、宇高利浩^*

SENSING PROPERTIES AND CATALYTIC DECOMPOSITION OF CARBON TETRACHLORIDE OF CuO-In₂O₃ THIN FILM SENSORS

Junya FUKUNISHI, Jun TAMAKI, Tomohiro KAWAGUCHI^*, and Toshihiro UDAKA^*

Department of Applied Chemistry, Faculty of Science and Engineering,
Ritsumeikan University, Kusatsu-shi, Shiga 525-8577, Japan
^*R&D Department, Figaro Engineering Inc., Mino, Osaka 562-8505, Japan

Previously, it was found that the CuO-In₂O₃ thin film sensor showed excellent sensing properties to CCl₄. The sensor resistance largely increased upon exposure to CCl₄. In this study, the effect of CuO loading on CCl₄ sensing properties was investigated and the catalytic decomposition of CCl₄ was carried out on CuO-In₂O₃ in order to elucidate the sensing mechanism. The excellent sensing properties to CCl₄ of CuO-In₂O₃ sensor were unchanged for various CuO loadings. The CCl₄ sensitivity increased with decreasing CuO loadings. The highest sensitivity (S=31 to 30 ppm CCl₄) was obtained at 0.1 wt% loading. From the results of catalytic decomposition of CCl₄, the addition of CuO enhanced the catalytic activity in CCl₄ decomposition, but suppressed the formation of CO₂. CCl₄ is decomposed on sensor surface to form C and Cl fragments. The C fragment reacts with adsorbed oxygen to CO₂, inducing the resistance decrease. The Cl fragment is negatively adsorbed on the surface to increase the sensor resistance. On 0.1 wt% CuO-In₂O₃ sensor, CO₂ is not formed at all and Cl^- adsorbate is effectively attributed to large resistance increase.

酸化タングステン薄膜マイクロセンサの二酸化窒素検知特性に及ぼす微小電極ギャップの効果

立命館大理工

○宮地　聖、牧の段次郎、小椋俊輔、小西　聡、玉置　純

EFFECT OF MICRO-GAP ELECTRODE ON NITROGEN DIOXIDE SENSING PROPERTIES OF TUNGSTEN OXIDE THIN FILM SENSORS

Akira MIYAJI, Jiro MAKINODAN^*, Shunsuke OGURA^*, Satoshi KONISHI^*, Jun TAMAKI

Department of Applied Chemistry, Faculty of Science and Engineering,
Ritsumeikan University, Kusatsu-shi, Shiga 525-8577, Japan
^*Department of Mechanical Engineering, Faculty of Science and Engineering,
Ritsumeikan University, Kusatsu-shi, Shiga 525-8577, Japan

Micro-gap electrodes with various gap widths (0.3-1.5 μm) were fabricated by means of MEMS techniques (photolithography and FIB techniques). The WO₃ thin film was deposited on the micro-gap electrode by using suspension dropping method to be micro-gas-sensor. The sensing properties to dilute NO₂ of WO₃ thin film microsensors were measured in the range of 0.01-3 ppm at 200 ℃ and the effects of micro-gap size on dilute NO₂ sensing properties were investigated. The sensitivity to dilute NO₂ was almost unchanged for the gap size larger than 0.85 μm. However, the sensitivity tended to increase with decreasing gap size less than 0.85 μm. The highest sensitivity (S=47 to 0.5 ppm NO₂) was obtained for the microsensor with gap width of 0.33μm. The effect of micro-gap was explained with related to the amount of WO₃ particles deposited between micro-gap.

SnO₂ガスセンサの動的応答の活用による取得情報量の増大

京都大学大学院理学研究科　物理学・宇宙物理学専攻

○小河原　達也

INCREASE OF INFORMATION IN SnO₂ GAS SENSOR WITH TIME-DEPENDENT DYNAMICAL RESPONSE

Tatsuya OGAWARA

Department of Physics,Graduate School of Science, Kyoto University,
Kyoto-shi, Kyoto 606-8502, Japan

The purpose of this research is to develop a novel intelligent gas sensor. Currently, it has been difficult to evaluate the concentration of different chemical species contained in a gas environment. It becomes possible to extract abundant information, if time-dependent trace of the sensor output is analyzed. We experimentally show that different kinds of monovalent alcohols can be identified and quantitated by using a single SnO₂ gas sensor.

空気質センサの開発と実用化による新市場開拓

フィガロ技研

○中原　毅

DEVELOPMENT OF GAS SENSORS AND CULTIVATION OF NEW MARKETS FOR AIR QUALITY

Takeshi NAKAHARA

FIGARO Engineering Inc., 1-5-11 Senba-nishi, Minoo-shi, Osaka 562-8505

We have developed gas sensors for air quality and put in the practical use in various applications.
(1) Semiconductor gas sensor for auto-damper control system: SnO₂ were adopted as sensing materials and Fe₂O₃ was doped to especially enhance the sensitivity to NO₂ emitted from diesel vehicles. The auto-damper control system showed good performance in damper control.
(2) Semiconductor gas sensor for VOC detection: WO₃ as a sensing material showed high sensitivity to volatile organic compounds such as toluene and xylene.
(3)Solid electrolyte CO₂ sensor:CO₂ sensor composed of NASICON（Na₃Zr₂Si₁₂PO₁₂）as a solid electrolyte and Li₂CO₃ as an auxiliary electrode was developed. La₂O₃ was doped in order to improve the sensing performance against humid conditions.

マイクロアレイ型オプティカル化学センサチップ

富山大工

○鈴木正康, 中林寛明, 本田　勝, 入部康敬

MICRO-ARRAYED OPTICAL CHEMICAL SENSOR CHIPS

Masayasu SUZUKI, Hiroaki NAKABAYASHI, Masaru HONDA, Yasunori IRIBE

Department of Electric and Electronic Engineering, Faculty of Engineering, Toyama University
Toyama-shi, Toyama 930-8555, Japan

Biochip technologies such as DNA chips, protein chips and cell chips are now attracting a great deal of attention. We are developing micro-well array chip system for parallel monitoring of single cell function. This micro-well array chip has a quarter million wells on one chip (ca. 20mm x 20mm), and diameter of each well is 10 micron and only one cell can be occupied for each well. In this study, we prepared optical pH sensors in each well for monitoring of cell activity. Fluorescein isothiocyanate (FITC) was covalently bound to the amino-group introduced slide glass (DNA chip grade), and polydimethylsiloxane(PDMS) film which has 10 micron diameter holes was put onto the glass. Fluorescence intensity of each well was measured by using a high resolution microarray scanner (ex. 473nm, em. 535nm).

半導体化学イメージセンサのマイクロ流路デバイスへの応用

阪大産研

宇井靖人, ○吉信達夫, 岩崎裕

APPLICATION OF THE CHEMICAL IMAGING SENSOR TO MICROFLUIDIC DEVICES

Yasuhito UI, Tatsuo YOSHINOBU, Hiroshi IWASAKI

The Institute of Scientific and Industrial Research, Osaka University
8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan

The chemical imaging sensor is a semiconductor-based sensor for visualization of the spatial distribution of ion concentration in the solution. In this study, a microfluidic channel was constructed on the sensing surface of the chemical imaging sensor. Visualization and temporal recording of the pH value in the channel are demonstrated.

界面張力を利用した微小送液機構とその化学センシングへの応用

筑波大物質工

○佐藤航，鈴木博章

MICRO FLUIDIC TRANSPORT SYSTEM BASED ON ELECTROWETTING AND ITS APPLICATION TO CHEMICAL SENSING

Wataru SATO, Hiroaki SUZUKI

Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

An on-chip microfluidic system was constructed which transports solutions in micro flow channels by deliberately controlling interfacial tension by electrode potential. The system consists of a flow channel, a reservoir, and a thin-film three-electrode system. By setting the potential of the working electrode at an appropriate value, interfacial tension between the solution and the working electrode is changed, resulting in the movement of the solution. The solution was transported in a space between the flow channel and the working electrode. Velocity of the solution increased as the height of the flow channel decreased. An air-gap ammonia electrode was formed in the mixing channel. Two solutions introduced from two injection ports could be mixed in the mixing channel by applying a potential to an intervening working electrode between the working electrodes for transport. When an ammonia standard solution and a NaOH solution were mixed, a distinct potential change was observed in the pH indicator electrode following the transport of the mixed solution. The 90% response time was 85 s for 10 mM ammonia.

微小流路底への高精度酵素固定法と超微量センシングシステムへの応用

筑波大物質工

○橋本正利，Sanjay Upadhyay，鈴木博章

PRECISE ENZYME IMMOBILIZATION AT THE BOTTOM OF A MICRO FLOW CHANNEL AND ITS APPLICATION TO A SENSING SYSTEM

Masatoshi HASHIMOTO, Sanjay UPADHYAY, Hiroaki SUZUKI

Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

A method to immobilize an enzyme precisely at the bottom of a micro flow channel was developed. A template was formed with silicone rubber, which was covered with a gold layer. An enzyme (glucose oxidase) was immobilized in a sol-gel matrix. The precursor solution was stamped on a protruding structure of the template. A precursor solution of silicone rubber was pored onto this structure. The cured silicone rubber was removed from the template. As a result, the enzyme was immobilized at the bottom of a flow channel. The flow channel with the immobilized enzyme was placed on a substrate with a three-electrode system. The dependence of the output current on device parameters was examined. The transport or diffusion of hydrogen peroxide in the flow channel could be detected from the output current. The current increased significantly as the flow rate decreased. Also, the current increased as the height of the flow channel decreased or the site of immobilized enzyme is distant from the working electrode.

モノリス酵素リアクターを用いた測定妨害物質の除去

NTT MI研、NTT-AT^*、国立循環器病センター^**

○林　勝義、陳　子林、岩崎　弦、栗田僚二^*、砂川賢二^**、丹羽　修

ELIMINATION OF ELECTROACTIVE INTERFERENTS USING AN ENZYME-MODIFIED MONOLITHIC REACTOR

Katsuyoshi Hayashi, Zilin CHEN, Yuzuru IWASAKI, Ryoji Kurita^*, Kenji SUNAGAWA^**, Osamu NIWA

NTT Microsystem Integration Labs.,
3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198
^*NTT Advanced Technology Corporation,
3-1 Morinosato Wakamiya, Atsugi, Kanagawa 243-0198
^**National Cardiovascular Center,
5-7-1 Fujishirodai, Suita, Osaka 565-8565

It is important to eliminate electroactive intereferents with high efficiency when the concentration of biomolecules is measured by using electrochemical method. Therefore various elimination methods have been studied to improve selectivity for neurotransmitters such as catecholamine and L-glutamate. Ascorbic acid and uric acid have considerable interference on the measurement of them.. In this work we have successfully developed a monolithic enzyme reactor for eliminating uric acid. Uricase and catalase were immobilized on the nano-porous surface of monolithic matrix and used for eliminating the uric acid. It was shown that uric acid could almost be removed by the monolithic enzyme reactor. We also improved elimination efficiency by using aminopropylmethoxysilane and glutaraldehyde to immobilize enzymes on a surface of silica monolith. Monolithic column is proved to be used to realize highly selective enzymatic reactor.

IER法を利用した水中溶存有機物(DOC)センサの開発

（有）オー・エス・ピー

○山口　恭子、山本　弘信

DOC SENSOR BASED ON AN INTERFERENECE ENHANCED REFLECTION TECHNOLOGY

Kyoko YAMAGUCHI, Hironobu YAMAMOTO

O.S.P. Inc.
3F Yamasho Bld. 2-14 Higashi-Mitsuki, Sayama-shi, Saitama, 350-1302 Japan

A dissolved organic compound (DOC) sensor was developed based on an interference enhanced reflection technology. Sensor chip prepared from a polymeric thin film coated on a glass substrate with a high refractive index was utilized for the detection of petrochemical hydrocarbons such as benzene and toluene, and chlorinated hydrocarbons such as trichloroethylene and tetrachloromethane in water down to the ppm order. A portable type sensor and a process monitor are applicable to simple, quick, and low-cost on-site survey and/or monitoring of water/soil contaminations.

鉄チオフリルポルフィリン電解重合膜の作製と電極触媒への応用

東理大理工、東理大界面科研

○石川満寿英、江口勝哉、小林朋宏、筒井　暁、豊田裕次郎、山口有朋、小柳津研一、湯浅　真

PREPARATION OF AN ELECTROPOLYMERIZED FILM OF IRON THIOFURYLPORPHYRIN AND APPLICATION TO AN ELECTROCATALYST

Masuhide ISHIKAWA, Katsuya EGUCHI, Tomohiro KOBAYASHI, Aatoshi TSUTSUI, Yujiro TOYODA, Aritomo YAMAGUCHI, Kenichi OYAIZU and Makoto YUASA

Faculty of Sci. and Technol., Tokyo Univ. of Sci.
Noda, Chiba 278-8501, Japan
Inst. of Colloid and Interface Sci., Tokyo Univ. of Sci.
Shinjuku, Tokyo 162-8601, Japan

A novel needle-type microsensor composed of a thin film of iron meso-tetrahiofurylporphyrin (TeT3ThP) at a carbon electrode was applied for the electrochemical detection of superoxide anion radiacl (O₂^-). This microsensor was prepared by means of electropolymerization of FeT3ThP in CH₂Cl₂ containing 10 mM TBAP as a supporting electrolyte, which gave a smooth film of the corresponding polymer. The film was electrochemically active to give a redox response near 0 V vs Ag/AgCl due to Fe^IIT3ThP = Fe^IIIT3ThP⁺ + e^-. The microsensor was applied to detect O₂^- produced by xanthine oxidase (XOD)-catalyzed hypoxanthine oxidation. The amperometric response for O₂^- was monitored at 0.5 V for 10 mM phosphate buffer. The microsensor displayed a high selectivity and activity for the oxidation of O₂^- and showed a linear relationship between the current and O₂^- concentration, which revealed a possibility of quantitative in vivo analysis of O₂^-.

ELECTROCHEMICAL OXIDATION OF INSULIN AT CONDUCTIVE DIAMOND ELECTRODES

慶大理工

○Ivandini A.Tribidasari, 藤嶋　昭, 栄長泰明

ELECTROCHEMICAL OXIDATION OF INSULIN AT CONDUCTIVE DIAMOND ELECTRODES

Tribidasari A. IVANDINI, Akira FUJISHIMA, Yasuaki EINAGA

Department of Chemistry, Faculty of Mathematics and Science, University of Indonesia
Kampus Baru UI Depok, Jakarta 15424, Indonesia
Academy of Science and Technology, KSP, 3-2-1 Sakado, Kawasaki 213-0012, Japan
Department of Chemistry, Faculty of Science and Technology, Keio University
3-14-1 Hiyoshi, Yokohama 223-8522, Japan

Electrochemical behavior of insulin has been investigated at conductive diamond thin film electrodes by cyclic voltammetry. Hydrogen-terminated surfaces have shown the superiority for insulin oxidation in terms of sensitivity. Insulin oxidizes at 〜1.0 V vs. SCE in pH 2 Britton Robinson buffer. Calibration plots were linear from 1μM to 6μM (r2=0.98). Although the current ;eaks decreased due to adsorption and oxidation of the surface, reduction method is found to be effective for recovery of the surface.

シリコーン有機超薄膜を被覆した微小電極によるNOセンシング

産総研、熊大、東北大

○加藤 大、國武 雅司、西澤 松彦、末永 智一、水谷 文雄

FABRICATION OF NITRIC OXIDE-MICROSENSORS MODIFIED WITH SILICONE ULTRATHIN FILMS

Dai KATO, Masashi KUNITAKE, Matsuhiko NISHIZAWA, Tomokazu MATSUE and Fumio MIZUTANI

National Institute of Advanced Industrial Science and Technology,
1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
Faculty of Engineering, Kumamoto University
Graduated School of Engineering, Tohoku University

Two-dimensional (2D) cross-linked polysiloxane Langmuir-Blodgett (LB) films were prepared and applied to the permselective membranes for nitric oxide (NO)-microsensors. The characteristic of the film is cross-linked structure between epoxy groups on the copolymer and amino groups on polyallylamine as a cross-linker at air-water interface. The 2D cross-linked siloxane LB films deposited on Pt microelectrodes were highly effective in eliminating interfering responses and had a rapid response for NO, even though the films were only a monolayer thick. The modified electrodes were very stable and could be used repeatedly for more than half a year without degradation as sensors.

電極へのポリイオン吸着によるルミノール電気化学発光法の高感度化

芝浦工業大学 応用化学科

○鎌田 正行、吉見 靖男

RAISING SENSITIVITY OF ELECTROCHEMILUMINESCENT SENSING METHOD WITH LUMINOL BY POLYION ADSORPTION ONTO ELECTRODE

Masayuki KAMADA，Yasuo YOSHIMI

Department of Applied Chemistry，Shibaura Institute of Technology，
Minato-ku，Tokyo 108-8548

The electrochemiluminescence（ECL）of luminol can be operated under completely mixed condition of solutions of luminol and hydrogen peroxide. However the ECL is yet to be applied for quantitative analysis of biochemicals due to low quantum yield in biochemical pH. We adsorbed polycation onto the electrode, and evaluated the effect of the adsorption to the ECL intensity of luminol in neutral buffer solution. As the result, the ECL intensity was dramatically increased by the polycation adsorption. The result indicates that polycation adsorbed on electrode enhances the ECL by elevating the pH in the vicinity of the electrode surface. This simple method is promising for highly sensitive determination of biochemicals using the ECL.

ナノ構造を有する水素化パラジウム微小電極pHセンサーの作製と特性評価

JFEスチール(株)^*，サウサンプトン大学^**

○妹川透^*，Guy Denuault^**

FABRICATION AND CHARACTERIZATION OF NANOSTRUCTURED PALLADIUM HYDRIDE MICROELECTRODE pH SENSORS

Toru IMOKAWA^*, Guy DENUAULT^**

^*Steel Research Laboratory, JFE Steel Corporation,
1 Kokan-cho, Fukuyama, Hiroshima 721-8510
^**Department of Chemistry, University of Southampton,
Highfield, Southampton SO17 1BJ, UK

An attempt was made to fabricate reliable potentiometric pH sensors with nanostructured Pd-hydride microelectrodes. First, nanostructured Pd films were electrodeposited on Pt microdisc electrodes using a molecular template created by a hexagonal liquid crystalline phase. While retaining micrometer dimensions these films possess huge electroactive surface areas; ie. typically 250 times greater than the original geometric surface areas. Nanostructured Pd films were then loaded with hydrogen cathodically. Thus prepared nanostructured Pd-hydride microelectrodes showed excellent potentiometric response over a wide range of pH (2-12). The response was rapid, stable, reproducible and almost theoretical in deaerated solutions.

電解系導入・FIAシステムを用いたアスコルビン酸のカロリメトリックセンシング

神奈川工科大工・応用化学科

○飯田泰広・秋葉邦人・佐藤生男

CALORIMETRIC DETERMINATION OF L-ASCORBATE USING AN FIA SYSTEM ARMED WITH AN ELECTROLYTIC DEVICE

Yasuhiro IIDA, Kunihito Akiba, and Ikuo SATOH

Department of Applied Chemistry, Faculty of Engineering,
Kanagawa Institute of Technology
1030 Shimo-Ogino, Atsugi-shi, Kanagawa-ken, 243-0292, Japan

In order to extend a determination range for biosensing with use of oxidase, an electrolytic device was developed and introduced into a calorimetric flow-injection system for L-ascorbate by using an immobilizing ascorbate oxidase column as a recognition element in combination with a substrate recycling method. The biosensing system was assembled with a plunger pump, the developed electrolytic device, the enzyme column unit, the calorimetric flow-type system, and a pen recorder. The electrolytic device enabled to increase dissolved oxygen in the assay streams by electrolyzing the carrier (50 mM citrate buffer), and thereby, the additional oxygen attributable to electrolysis should be provided to the ascorbate oxidase column and should contribute to an activation of the ascorbate oxidase-catalyzed reaction.
A 1,4-dithiothreitol (DTT) was used as a reducing agents to regenerate L-ascorbate from dehydroascorbate. L-Ascorbate solutions (100 ul) with various concentrations were injected into the system with or without DTT solution and the temperature responses were calorimetrically monitored. Use of the recycling method delivered the temperature response, which was twofold over those of the DTT-free samples. However, the higher limit of detection of L-ascorbate became lower due to the increase in amount of consumption of dissolved oxygen in the carrier solution. Therefore, the electrolytic device to increase amount of dissolved oxygen in carrier solution was introduced into the FIA system. A wider linear range of the L-ascorbate determination was obtained with use of the device. This study exemplified that the combination of application of the recycle method for determination of L-ascorbate and use of the electrolytic device should provide the sensitive and wide range determination for L-ascorbate.

アスコルビン酸オキシダーゼカラム・FIAシステムを用いたカロリメトリックバイオセンシング

神奈川工科大工・応用化学科

○佐藤生男・若菜勇弥・飯田泰広

CALORIMETRIC BIOSENSING USING AN FIA SYSTEM ARMED WITH AN ASCORBATE OXIDASE COLUMN

Ikuo SATOH, Yuya WAKANA, and Yasuhiro IIDA

Department of Applied Chemistry, Faculty of Engineering,
Kanagawa Institute of Technology
1030 Shimo-Ogino, Atsugi-shi, Kanagawa-ken, 243-0292, Japan

A flow-calorimetric sensing system armed with an ascorbate oxidase column as a recognition element was applied to microdetermination of copper(II) ions. The enzymes covalently immobilized onto porous glass beads with controlled pore size (24.2 nm) were packed into a small polymer column. The enzyme-column was inserted into a temperature probe and then, placed in a thermostated aluminum cylinder. Variations in temperature responses attributable to the enzyme-catalyzed reaction were monitored successively. Introduction of 0.5 mL of 20 mM N,N-diethyldithiocarbamate solution(DDTC, pH 8.0) caused significant decrease in the catalytic activity of the column. Recovery of the temperature responses was observed by subsequent addition of copper(II) ions solution. The column activity was a function of copper(II) ions injected. Thus, copper(II) ions in a range of 1.0 to 10 uM could be calorimetrically determined.

金属吸着ウレアーゼの酵素活性を利用する酵素センサに関する研究

埼玉工大工

○内山俊一、関岡直行

STUDY ON ENZYME SENSOR USING THE UREASE ADSORBED METAL NETS Shunichi UCHIYAMA, Naoyuki SEKIOKA

Department of Applied Chemistry, Faculty of Engineering, Saitama Institute of Technology,
1690 Fusaiji, Okabe Saitama 369-0293 Japan

Urease extracted from jackbean has many SH groups, and these groups can be directly electrolyzed at carbon and gold electrodes because SH groups exist at near surface of protein molecule. In this research, the adsorption of urease to the metal surfaces such as gold or silver, and we found that the adsorbed urease activities are considerably changed by the kind of metal. We measured the urease enzyme activity by using ammonia electrode with urease adsorbed metal nets. The activity of adsorbed urease to silver and copper nets were much lower than that to gold net, and the low activity of adsorbed to silver net was dramatically recovered by addition of dithiothreithol, but the adsorbed urease to copper net was not recovered immediately. The reason why the activities of adsorbed urease to silver and copper meshes are decreased is considered to be change of conformation of urease by adsorbing not only SH groups but also disulfide bond.

新規な担体架橋法を利用した酵素固定法の開発

横浜国大院環境情報

○許一太、雨宮隆、伊藤公紀

Development of the enzyme immobilization method for having used the new carrier constructing-bridge method

Yitai XU, Takashi AMEMIYA, Kiminori ITOH

Gradute School of Environment and Information Science, Yokohama National University, Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan

It is an important subject to immobilized protein to the transducer of a sensor in the study of the biosensor using the biochemistry reaction. The carrier constructing-bridge method using the conventional glutaraldehyde was improved, and this research examined the method aiming at construction of the efficient and quick protein immobilization. The siloxane film which played an important role in enzyme immobilization, was formed by hydrolyzed 3-aminopropyltrimethoxy -silane. The immobilization of enzyme was realized in about 3-4 hours.

マイクロマシーニングによる化学センサの微小化、集積化、システム化

筑波大物質工

○鈴木博章

MINIATURIZATION, INTEGRATION, AND SYSTEMIZATION OF CHEMICAL SENSORS USING MICROMACHINING TECHNIQUES

Hiroaki SUZUKI

Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan

Microfabrication technology for electrochemical sensors has advanced dramatically over the last two decades. Furthermore, in a trend of the μTAS or Lab-on-a-Chip research, the electrochemical sensors have been incorporated in various micro systems including micro fluidic and arrayed devices. The use of electrochemistry is not limited to the sensors. Micro pumps and valves based on electrochemical principles are advantageous for the construction of integrated micro fluidic systems because of their simple structure and principle of operation along with low operational voltage and power consumption. With the advent of the 21st century, the basic technologies for sensing and actuation are beginning to be used in highly sophisticated micro systems. In this report, the advance in micro electrochemical sensors, actuators, and systems is presented along with future prospects.

高分子交互累積膜法を利用した過酸化水素検出型キサンチンセンサ

東北大院薬

○星 友典、野口 多紀郎、安斉 順一

Amperometric xanthine sensors based on polyelectrolyte multilayer films

Tomonori HOSHI,Takio NOGUCHI, Jun-ichi ANZAI

Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku,
Sendai 980-8578, JAPAN

Platinum electrodes coated with a poly(allylamine)/poly(vinylsulfate) film can be used for detecting H₂O₂ selectively in the presence of the possible interfering agents such as ascorbic acid, uric acid. Xanthine oxidase (XOx) was then deposited on the polyelectrolyte multilayer films with poly(diallyldimethylammonium chloride) through electrostatic interaction. The response current for xanthine increased with increasing the number of layers of XOx. The xanthine sensor showed calibration response to xanthine over the concentration range of 1 -300 mM successfully. Though the response of the sensor to uric acid was negligible even after 31 days, the response of the sensor to xanthine was decreased by 95 % from the original activity .

SPR免疫センサよる爆発性ニトロ芳香族化合物の高感度検出

九州大学¹、科学技術振興機構²

○ D. ラビ シャンカラン^1,2, K. V. ゴビ¹, 松本清¹, 今任稔彦¹, 都甲潔¹, 三浦則雄¹

HIGHLY SENSITIVE DETECTION OF NITROAROMATIC EXPLOSIVE MOLECULES BASED ON SURFACE-PLASMON-RESONANCE IMMUNOSENSOR

○ Dhesingh RAVI SHANKARAN^1,2, K. Vengatajalabathy GOBI¹, Kiyoshi MATSUMOTO³, Toshihiko IMATO⁴, Kiiyoshi TOKO⁵, Norio MIURA¹

¹Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga-Shi, Fukuoka 816-8580, Japan
²Japan Science and Technology Agency
³Graduate School of Agriculture, Kyushu University, Fukuoka, 812-8581, Japan
⁴Graduate School of Engineering, Kyushu University, Fukuoka 812-8581, Japan
⁵Graduate School of Information Science and Electrical Engineering, Kyushu University, Fukuoka, 812-8581, Japan

A novel surface-plasmon-resonance immunosensor (SPR) capable of detecting nitroaromatic explosive compounds at ppt level concentration has been developed based on the principle of indirect competitive immunoreaction. 2,4,6-Trinitrophenol-Bovine Serun Albumin (TNP-BSA) conjugate was immobilized onto a SPR gold chip by physical adsorption. The immunoreaction between TNP-BSA conjugate and anti-TNP antibody was inhibited in the presence of nitroaromatic analytes. The extent of inhibition depends on the concentration of analyte, which was utilized for their quantification. The sensor exhibited excellent sensitivity for the detection of 2,4,6-trinitrotoluene (TNT) and TNP in a wide concentration range from 0.06 ppb to 1000 ppb and 0.01 ppb to 100 ppb, respectively. Regeneration of the sensing surface for multiple analyses can be effected using pepsin solution. The immunosensor exhibited good selectivity, reproducibility and stability, which can be extended to the determination of other nitroaromatic explosive compounds for application to on-site detection of landmines.

自己組織化単分子層を用いたＳＰＲ免疫センサによる環境ホルモンの検出

九大産学連携センター ¹, 日本学術振興会 ², 京都電子工業 ³

○K. V. ゴビ^1,2、片岡千和³、三浦則雄¹

SURFACE PLASMON RESONANCE DETECTION OF ENDOCRINE DISRUPTORS USING IMMUNOPROBES BASED ON SELF-ASSEMBLED MONOLAYERS

K. Vengatajalabathy GOBI ^1,2, Chiwa KATAOKA ³, Norio MIURA ¹

¹ Art, Science and Technology Center for Cooperative Research, Kyushu University, Kasuga, Fukuoka 816-8580
² Japan Society for the Promotion of Science (JSPS)
³ Kyoto Electronics Manufacturing, 68 Ninodan-cho, Shinden, Kisshoin Minami-ku, Kyoto 601-8317, Japan

A monolayer of benzo[a]pyrene (BaP)-derivative is formed on a gold-coated chip with benzo[a]pyrene units exposing out of the sensor surface for surface plasmon resonance (SPR) sensing of BaP. The BaP-derivative was immobilized by covalent binding with a compact self-assembled mixed-monolayer of cysteamine. Interfacial interaction of an antibody against BaP (BaP-antibody) with the monolayer is studied by SPR-angle interrogation method. BaP-antibody undergoes selective immunoreaction with the sensor surface thus prepared and immobilizes firmly. Flow of high concentrations of bovine serum albumin showed negligible increase in the SPR response indicating high resistivity of the sensor surface to non-selective adsorption of proteins. With presence of BaP together in the analyte solution, the immunoreaction of BaP-antibody with the sensor surface is found inhibited. Extent of the inhibition of immunoreaction by the presence of BaP is analyzed in determining the concentration of BaP. Using the present sensor, BaP is determined as low as 30 ppt with a response time of ≦ 20 min. After the use in the determination of BaP by immunobinding, active sensor surface is generated again by the treatment of pepsin for dissociation of the antigen-antibody complex. A same sensor chip was usable in the determination of BaP concentration repeatedly for more than 10 cycles without significant decrease in the sensor activity.

電気泳動型免疫センサ

石川県産創支援機構，�叶ﾎ川製作所^（１），北陸先端大院・材料^（２）

○井手上公太郎，小林正昭，市川　央^（１），森田資隆^（２），民谷栄一^（２）

THE DEVELOPMENT OF A MICROCHIP ZONE ELECTROPHORESIS-BASED IMMUNOSENSOR

Koutarou IDEGAMI, Masaaki KOBAYASHI, Hiroshi ICHIKAWA^（１）, Yasutaka MORITA^（２）, Eiichi TAMIYA^（２）

Ishikawa Sunrise Industries Creation Organization,
Tatsunokuchi, Ishikawa 923-1211,
^（１）Ishikawa Seisakusho, LTD.
Matto, Ishikawa 924-0051
^（２） School of Materials Science, Japan Advanced Institute of Science and Technology
Tatsunokuchi, Ishikawa 923-1292

The development of a novel immunosensor based on microchip zone electrophoresis in connection with a fluorescence detection system is described for application in the point-of-care clinical diagnosis. Microchips have become increasingly popular because of their small size along with low sample volume requirements. In this report, wells were microfabricated on a polyacrylamide gel, which was the supporter of the microchannels on silicon substrate. In consequence to the specific reaction between anti-human albumin antibody and the labeled antigen in the wells, free and bound labeled antigen were separated by zone electrophoresis. The quantification of antigens was performed by monitoring the fluorescence signal with a microscope. Anti-human albumin antibody could selectively be detected with a linear range between 1 and 100 mg/ml in about 40 min.

免疫クロマトグラフィーを用いたPCB測定法の開発

^*(株)ｴﾝﾊﾞｲｵﾃｯｸ・ﾗﾎﾞﾗﾄﾘｰｽﾞ、^**国立環境研究所、^***北陸先端科学技術大学院大学

○西　和人^*、奥山　亮^*、竹中　宏誌^*、水上　春樹^*、滝上　英孝^**、遠藤　達郎^***、森田　資隆^***、民谷　栄一^***、酒井　伸一^**、森田　昌敏^**

DEVELOPMENT OF IMMUNOCHROMATOGRAPHIC ASSAY FOR POLYCHLORINATED BYPHENYS

Kazuto NISHI^*,Akira OKUYAMA^*, Hiroshi TAKENAKA^*,Haruki MIZUKAMI^*,Hidetaka TAKIGAMI^**,Tatsuro ENDO^***,Yasutaka MORITA^***, Eiichi TAMIYA ^***,Shin-ichi SAKAI^**,Masatoshi MORITA^**

^*EnBioTec Laboratories,
Ikeda Rika Bldg., 2nd Floor 586-9Akatsuka, Aza Ushigafuchi, Tsukuba, Ibaraki 305-0062
^**National Institute for Environmental Studies,
Onogawa 16-2, Tsukuba, Ibaraki 305-8506
^***School of Materials Science, Japan Advanced Institute of Science and Technology,
1-1 Asahidai, Tatsunokuchi, Ishikawa 923-12

Polychlorinated biphenyls (PCBs) are one of the major concerns in environmental contaminants because of their toxicity to human and wildlife, and the development of a reliable screening method has been desired. We developed a new type of imuunochromatographic assay for semi-qualification of PCBs by using monoclonal antibody against 2,3', 4,4', 5- pentachlorobiphenyl (IUPAC#: PCB #118). The assay reacted with Kanechlor (KC) series by different sensitivity (KC300 : 0.7 ppm, KC400 : 0.2 ppm, KC500 : 0.1ppm, KC600 : 0.5 ppm). Also the assay showed good results for recovery test with soil model samples. Because the new assay is simpler than enzyme-linked immunosorbent assay (ELISA), it could be very useful tool for PCB screening in soil samples.

抗体アレイチップを用いた多項目同時分析デバイスの開発

東北大院工・院環境^*，第一化学薬品(株)^**，(株)アイ・ティ・リサーチ^***

○ 小笠原大知^*，平野悠^*，安川智之^*，珠玖仁^*，末永智一^*，小堀樹一郎^**，牛澤幸司^**，川端荘平^**

Simultaneous Electrochemical Immunoassay with Protein Microarray

Daichi OGASAWARA^*, Yu HIRANO^*, Tomoyuki YASUKAWA^*, Hitoshi SHIKU^*, Tomokazu MATSUE^*, Kiichirou KOBORI^**, Kouji USHIZAWA^**, Souhei KAWABATA^***

^*Graduate School of Environmental Studies, Tohoku University,
07 Aoba, Aramaki, Aoba, Sendai 980-8579, Japan
^**Daiichi Pure Chemical Co., Ltd.,
3-13-5 Nihonbashi, Chuuou, Tokyo 103-0027, Japan
^***I.T.Research Co., Ltd.,
2-1-40-311 Takamori, Izumi, Sendai 981-3203, Japan

We have investigated the simultaneous electrochemical immunoassay by assembling a chip electrode and a protein-arrayed chip into a chip holder. This novel “chip to chip detection” ultimately allows that microelectrodes on a chip electrode and cavities for the protein immobilization on a protein arrayed chip are exactly faced each other. The sandwich immunoassay was conducted on the cavities using a model protein, pepsinogen2 (PG2) labeled with a horseradish peroxidase (HRP)-conjugated antibody (anti-mouse IgG). The measurement solution contained 0.5 mM ferocenemethanol (FMA) and 0.1 mM H₂O₂ as the substrate of HRP. To detect the antigen, amperometry was used at a constant potential (120 mV). Oxidized form of FMA generated by the enzyme reaction of HRP in each cavity was simultaneously detected by the corresponding electrodes addressed there. The current response was sensitive to the concentration of PG2 in the range of 1-30 ng/ml.

金表面への蛋白吸着を利用した尿蛋白センサの可能性の検討

国立リハ研究所

○青木一仁，外山滋

An approach of simple uric protein sensor by the use of direct protein adsorption onto gold surface

K.Aoki, S.Toyama

Research Institute, National Rehabilitation Center for the Persons with Disabilities
4-1 Namiki Tokorozawa-shi, Saitama, 359-8555 JAPAN

A simple approach of uric protein sensor was examined. A surface plasmon resonance (SPR) sensor was applied to detect proteins by the use of direct protein adsorption onto the sensor surface since the strict distinction such as immuno-sensors might not be always indispensable. A flow injection analysis (FIA) sensing system was used for ability tests of this method. At first, some acids, alkalis and surfactants were applied to remove the protein adsorbed on the gold surface in order to reproduce the sensor response. Efficient recovery of the sensor response was established when an alkali rinse was applied. And the sensor response had a correlation with the concentration of the proteins such as bovine serum albumin (BSA). The reproducible lower detection limit was determined using human serum albumin (HSA) and resulted as 500 μg/dl. Since the detection limit of urine test strip is usually 15-30 mg/dl, this approach has enough potential. Moreover, the influence of urine components for the measurement seems small because the responses of control urine with and without 10 mg/dl BSA have enough difference. Furthermore, it was suggested that the measurement might be performed within 90 sec. because the difference between the responses was detected immediately after the injection of the sample.

藻類固定化電極を用いた環境毒性物質検出法の開発

東大生研

○四反田功，高田主岳，酒井康行，立間　徹

DEVEROPMENT OF AMPEROMETRIC ALGAL BIOSENSOR FOR THE DETECTION OF ENVIRONMENTAL TOXIC COMPOUNDS

I. Shitanda, K. Takada, Y. Sakai, T. Tatsuma

Institute of Industrial Science, University of Tokyo,
4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan

Unicellular microalga Chlorella vulgaris was entrapped in an alginate gel or a polyion complex menbrane coated on the surface of an indium tin oxide electrode. Photosynthetic activity of the immobilized algae was monitored amperometically. Responses of the algal biosensor to various toxic compounds including herbicides were collected as inhibition ratios of photosynthetic oxygen evolution. Selectivities of the biosensor to a few selected compounds were roughly in agreement with those of the conventional standard growth test. The present method allows rapid detection of the compounds within a few minuites and establishment of a compact analytical system.

微生物チップを用いた電気化学計測による高感度変異原スクリーニング

東北大院環境科学・院工

○松井伸人，長峯邦明，彼谷高敏，安川智之，珠玖仁，末永智一

HIGHLY SENSITIVE ELECTROCHEMICAL MUTAGEN SCREENING WITH MICROBIAL CHIP

Nobuto MATSUI，Kuniaki NAGAMINE，Takatoshi KAYA，Tomoyuki YASUKAWA，Hitoshi
SHIKU，Tomokazu MATSUE

Graduate School of Environmental Studies and Department of Biomolecular
Engineering，Graduate School of Engineering，Tohoku University，Sendai
980-8579, Japan

Mutagens are known to induce the SOS response through DNA damage．An assay system named umu test has been developed to evaluate SOS mutagenesis and widely known as a good preliminary screening method．In the present study， we applied umu test to electrochemical mutagen screening．Salmonella typhimurium TA1535/pSK1002，in which a plasmid pSK1002 carrying a fused gene umuC’-‘lacZ has been introduced，was embedded using collagen gel in a micropore (5 nL) on the glass substrate．β-Galactosidase activity induced by mutagen was measured by scanning electrochemical microscopy (SECM)．The activity of the induced β-galactosidase was determined using p-aminophenyl-β-D-galactopyranoside (PAPG) as a substrate．This experiment showed that the current response was correlated with mutagen concentrations in the range from 0.0005 μg/ml to 0.5 μg/ml．Therefore，we suggested that this system can be used in mutagen screening．

BIOELECTROCHEMISTRY OF MOLECULAR OXYGEN AND REACTIVE OXYGEN SPECIES 122.
O₂ GAS SENSOR USING SUPPORTED HYDROPHOBIC ROOM-TEMPERATURE IONIC LIQUID MEMBRANE-COATED ELECTRODE

R. Wang, ○S. Hoyano T. Okajima, F. Kitamura, T. Ohsaka

Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology
4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan

A solid state amperometric O₂ gas sensor was successfully fabricated by using supported 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMIPF₆) porous polyethylene membrane as a solid-state electrolyte. The present O₂ gas sensor, which is capable of being operated at room temperature, shows a wide detection range and a high sensitivity.

Bioelectrochemistry of molecular oxygen and reactive oxygen species 123.electroanalysis of Peroxyacetic Acid and H₂O₂:use of iodide/iodine couple as a probing potential buffer

Mohamed Ismail Awad and Takeo Ohsaka

Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan

A simple and rapid potentiometric method for the simultaneous analysis of peroxyacetic acid (PAA) and hydrogen peroxide (H₂O₂) has been proposed using glassy carbon (GC) as an indicator electrode and I₂/I^- as a probing potential buffer. On the basis of the large difference in the reaction rates of PAA and H₂O₂ with I^-, a transient potential response corresponding to the reactions of the two species with I^- was observed, typically a few seconds and several minutes for PAA and H₂O₂, respectively. The effects of the concentrations of molybdate catalyst, H⁺, I₂, and I- in the potential buffer on the selectivity as well as the sensitivity were examined. The potential response obtained using the GC indicator electrode was found to be Nernstian over a wide range of their concentrations (typically from micromolar to millimolar) with slopes of 30.5 and 29.5 mV for PAA and H₂O₂, respectively (in close agreement with the theoretical value, that is, 29.6 mV). O₂ was found to have no substantial effect on the potential change at the GC electrode in the present potential buffer.