Vol. 14, Supplement A (1998)

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

Abstracts


1.

ƒ]ƒ‹—n‰t‚©‚ç’²»‚µ‚½ƒAƒ“ƒ`ƒ‚ƒ“Ž_ˆŸ‰”Œú–ŒƒZƒ“ƒT‚Ì‹É’á”Z“x—°‰»…‘f‚ɑ΂·‚錟’m“Á«

ŽR“c‰À”ŽA‹Ê’u@ƒAŽR–{‘PŽjA¼‰ª­•vA‘¾“c—E•v*

—§–½ŠÙ‘嗝HE“úŽY‰»Šw*

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iZnSb2O6jthick 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 Ž. The electrical resistance of the film was the highest when the film was calcined at 900-950 Ž. The film calcined at 900 Ž 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.

SmFeO3Œú–Œ‚Ì•\–ʏó‘Ô‚ÆNO2ƒKƒX‰ž“š

Â–ìG’ʁAƒGƒ“ƒŠƒREƒgƒ‰ƒxƒ‹ƒT*AƒXƒeƒtƒ@ƒmEƒrƒ‰ƒ“ƒ`A’艪–F•F

ˆ¤•Q‘åHEƒ[ƒ}‘å "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 ƒ¿-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 ƒ¿-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% ƒ¿-terpineol compared with that with non ƒ¿-terepineol.

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3.

ƒrƒXƒ}ƒXŒnŽ_‰»•¨”¼“±‘Ì‚ð—p‚¢‚½ NOƒZƒ“ƒT

_ìWKAŽðˆä@„AŽO‰Y‘¥—YAŽR“Y@úf

‹ã‘呍‡—H

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Ž. 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.

ˆê”¼“±‘Ì‘fŽq‚ð—p‚¢‚½ƒjƒIƒC‚ÌŽ¯•Ê

‚“c@‹`

VƒRƒXƒ‚ƒX“d‹@

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.

–ŒŒú‚¨‚æ‚уwƒeƒ\‘¢‚𐧌䂵‚½ In2O3ŒnŒú–ŒŒ^ƒZƒ“ƒT‚Ì n-C4H10ŒŸ’m“Á«


ìŒ´º•FAŸ–؍GºA]“ª@½*

²‰êŒ§—q‹Æ‹ZpƒZƒ“ƒ^[E’·è‘åH*

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Ž 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Ž. 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.

ƒoƒŠƒXƒ^Œ^ƒKƒXƒZƒ“ƒT‚̌𗬃Cƒ“ƒs[ƒ_ƒ“ƒX–@‚É‚æ‚éƒKƒXŒŸ’m‹@\‚̉ð–¾

•º“ªŒ’¶A‹à‘ò‰pˆêA‚”ö—Y“ñ*A´…N”ŽA]“ª@½

’·è‘åHAŠÂ‹«*

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[C .

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7.

…‘f‘I‘𐫔MüŒ^”¼“±‘ÌŽ®ƒZƒ“ƒT


•Ÿˆä ´AŸ–Ø Í

VƒRƒXƒ‚ƒX“d‹@Š”Ž®‰ïŽÐ

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 (0.50mmƒÓ) covering over a platinum wire (0.02mmƒÓ) 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.

Ž_‰»ƒXƒYŒnƒZƒ“ƒT‚É‚¨‚¯‚鎼“xˆË‘¶«‚̉ü‘P


@ •Ÿˆä ´AŸ–Ø Í

VƒRƒXƒ‚ƒX“d‹@Š”Ž®‰ïŽÐ

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 mmƒÓ) to cover a platinum wire (0.020 mmƒÓ) 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.

”––Œ‹Zp‚ÆŽ©“®ŽÔ‚ւ̉ž—p

‘½‰êNŒP

–L“c’†Œ¤

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 NOx sensors. Finally, further challenges to applications of thin films to the automobile sensors are discussed.

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j1.

ŠÂ‹«•Û‘S—p‚𒆐S‚Æ‚·‚éV‚µ‚¢‚«”\ƒKƒXƒZƒ“ƒT‚ÌŒ¤‹†ŠJ”­


ŽO‰Y‘¥—Y

‹ãB‘åŠw‘‡—H

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.

ƒWƒ‹ƒRƒjƒAƒZƒ‰ƒ~ƒbƒN‚ð—p‚¢‚½‚‰·Ž¼“xŒv‚ÌŠJ”­

”ª–؏G–¾

“ú–{“ÁŽê“©‹ÆŠ”Ž®‰ïŽÐ

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.

“d’r‹ì“®Œ^ SnO2Œn COƒZƒ“ƒT

“¡X—TŽ÷A–،Ր^‹IA–쑺“OA’†Œ´@‹BA¼‰Y‹g“WA–ƒ¶@Œ÷

ƒtƒBƒKƒ‹ZŒ¤

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.

Ž_‰»ƒXƒYŒnƒKƒXƒZƒ“ƒTo—Í‚ÆŽº“à‰·”MŠÂ‹«Žw”‚ÌŠÖŒW

‘ååM‘½‰ÂŽuC¬–쎛•*C¼‰Y‹g“W**C‘ååM–M’j***

‹à‘òŒoÏ‘åC‹à‘ò‘åEH*CƒtƒBƒKƒ‹ZŒ¤**C‘ååMŒšÝ***

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.

Ž_‰»ƒXƒY‚ð—p‚¢‚½”MüŒ^”¼“±‘ÌŽ® CO‘I‘𐫃Zƒ“ƒT


²“¡•ŽiAŽO‹´O˜aA‚‹´Ë•v

VƒRƒXƒ‚ƒX“d‹@(Š”)

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% PbOx and 0.5 atm% Nd2O3. This sensor had high sensitivity and selectivity to CO even at high sensor temperature of 300Ž, 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.

Ž©“®ŽÔ—pŽ©“®Š·‹C‘•’u‚ÌŽŽì


’†ì ‰pŒ³A‰ªèTŽiA•Ÿ“cŒ’ŽOA’©‘qjŽ¡AH–{‰p—Y*Ad·“OŽu**A‚‹´Ë•v**

‰¡•l‘‘åEHAƒG[ƒV[ƒC[*AVƒRƒXƒ‚ƒX“d‹@**

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.

Ž_‰»•¨“d‹É‚ð—p‚¢‚½ŒÅ‘Ì“d‰ðŽ¿Œ^ NOxƒZƒ“ƒT‚ÌŒŸoŠ´“x§Œä

’†‘º’‰ŽiC²Ž¡Œ[ŽsCŽR‰ºŸŽŸ

–L“c’†Œ¤

SENSITIVITY CONTROL OF SOLID ELECTROLYTE NOx 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 NOx-O2-N2 mixtures at temperatures higher than 600Ž. 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 NOx 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Ž.

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14.

Pb-Ru-OŒnƒpƒCƒƒNƒƒAŒ^Ž_‰»•¨“d‹É‚ð—p‚¢‚½ŒÅ‘Ì“d‰ðŽ¿ NOxƒZƒ“ƒT


´…—zˆêA¼@—T”üAŽR‰º“ì”ü

‹ãH‘åH

SOLID ELECTROLYTE NOx 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 NOx sensors using pyrochlore-type oxide (Pb2-xA'xRu2-yB'yO7-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Ž. 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 Pb2Ru1.9V0.1O7-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.

¬¬“dˆÊ‚ð—˜—p‚µ‚½ƒvƒƒsƒŒƒ“ƒZƒ“ƒT‚ÌŠJ”­

“ú”ä–썂ŽmAŒKŒ´@DF

–¼ŒÃ‰®H‹Æ‹ZpŒ¤‹†Š

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Ž,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.

•ª‹É•ûŽ® NOxƒZƒ“ƒT‚̍쓮‹@\‚ÆŠ´“x“Á«


‚ @‰]’qAŒµ@‰i“SA‘Œ³@WAŽO‰Y@‘¥—YAŽR“Y@úf

iŠ”jƒŠƒPƒ“A‹ã‘呍‡—H

WORKING MECHANISM AND SENSING CHARACTERISTICS OF POLARIZATION TYPE NOx 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 NOx at high temperatures. The sensor showed quick potential response and NOx totality to NO and NO2 at 550-650Ž, 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 NOx concentration in the range of 0-500 ppm.

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17.

Na+ “±“d‘Ì(NASICON)‚ð—p‚¢‚½‘S NOx Œv‘ª—pƒAƒ“ƒyƒƒƒgƒŠƒbƒNƒZƒ“ƒT

¬–쐳Ž÷A“‡ƒm]Œ›„AŽO‰Y‘¥—YAŽR“Y@úf

‹ã‘呍‡—H

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

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 NOx (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Ž. 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 NOx sensing mechanism of the present sensor was briefly discussed.

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18.

”’‹àŒŸo‹É‚ð—p‚¢‚½ PbCl2ŒÅ‘Ì“d‰ðŽ¿Œní‰·Œ^‰–‘fƒKƒXƒZƒ“ƒT

VŠÖ—Ç•vAŽÄ“c–ΗY

“Œ–kH‘å

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F Pb „  PbCl2{1 mol“ K2SO4{10 mol“ Al2O3 „  Pt-black, Cl2(x “)D 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.

ƒjƒgƒƒ\ƒjƒEƒ€ƒCƒIƒ“‚ð“`“±Ží‚Æ‚·‚éŒÅ‘Ì“d‰ðŽ¿‚ð—p‚¢‚½ NOxƒZƒ“ƒT

ŽR–{‹M¶A“c‘º^Ž¡A¡’†MlA‘«—§‹á–ç

ã‘å‰@H

NOx 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 NOx 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EAlCl3 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•µˆÍ‹C’†‚Ì Au/Li2CO3Œn“d‹É”½‰ž‹@\

Æˆä–ÎŽ÷AŠJ•Ä“ÄŽuA‰Í‘ºŒ›ˆêA“ñ“‚—TAì“c’B–çA…èƒˆê˜YA“cì”ŽÍ*

“Œ–k‘å‰ÈŒ¤EŠÂ‹«ƒGƒlƒ‹ƒM[‰ÈŒ¤*

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, ƒÐE, was strongly depended on PO2, proportional to (PO2)]1/2 in the high PO2 region and iPO2j0 in the low region. Dependence of ƒÐE on PCO2 was very weak. TheƒÐE could be formulated to ƒÐE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 ƒÑ(= CE / SƒÐE), where S is apparent contact area between the electrode and the solid electrolyte, is mainly affected by PO2 because of the dependency of ƒÐE on PO2.

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21.

NASICON‚Æ Li2CO3-CaCO3•â•‘Š‚ð—p‚¢‚½ CO2ƒZƒ“ƒT‚̉ž“š“Á«‚ÆŠE–ʍ\‘¢

“‡ƒm]Œ›„AìŽèGŽ÷AŽO‰Y‘¥—YAŽR“Y@úf

‹ã‘呍‡—H

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Ž while Li2CO3 did down to 350Ž.
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‚ð—p‚¢‚½’YŽ_ƒKƒXƒZƒ“ƒT‚ÌŠJ”­

X–{MŽiA¼Œ´³ŒáAŽu…ÍˆêA‹àŽqMˆê˜YAÎŒ´’B–¤*A‘ê“c—Sì*

‹ãB¼‰º“dŠíE‘啪‘åŠwH*

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Ž90% 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Ž. The measurement error of CO2 concentration was within 200 ppm in the humidity range of 40% to 90% RH, and within 30 ppm/Ž in the temperature range of 5Ž to 50Ž. These results show that the developed CO2 sensor may be applicable to IAQ monitoring systems.

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23.

Ã“d—e—ÊŒ^’YŽ_ƒKƒXƒZƒ“ƒT‚ÌŒŸ’m‹@\‚̍lŽ@

¼Œ´³ŒáA‹àŽqMˆê˜YAX–{MŽiAŽu…ÍˆêAÎŒ´’B–¤*A‘ê“c—Sì*

‹ãB¼‰º“dŠíE‘啪‘åŠw*

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-ƒÂ-Oad-CO2.

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24.

•ªŽq’’Œ^–@‚ð—p‚¢‚½ CuO-BaTiO3•¡‡Ž_‰»•¨‚̍쐻‚Æ—e—ÊŒ^CO2ƒZƒ“ƒT

‚–؏rºAÎŒ´’BŒÈA”óŒû³˜aAˆÉ“¡³ŽÀ*A‘ê“c—Sì

‘啪‘åHE‘啪‘å’nˆæ‹¤“¯Œ¤‹†ƒZƒ“ƒ^[*

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–Œ‚̃‰ƒCƒ“Œ^Œõƒtƒ@ƒCƒo…‘fƒZƒ“ƒT‚Ö‚Ì“K—p

ŠÖ–{T“ñ˜YA‰ªèTŽiA’†ì‰pŒ³A’©‘qjŽ¡A•Ÿ“cŒ’ŽOAd·“OŽu*A‚‹´Ë•v*

‰¡•l‘‘åHAVƒRƒXƒ‚ƒX“d‹@*

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.

ƒvƒ‰ƒYƒ}Ž_‰»–@‚Å’²»‚µ‚½Ž_‰»ƒjƒbƒPƒ‹”––Œ‚É‚æ‚éŒõŠw“IŽ¼“xŒŸ’m


ˆÀ“¡¹‹VA²“¡‹`KA“c‘º”ÉŽ¡A¬—Ñ“N•F

‘åHŒ¤

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.

‰Â—n«ƒ|ƒŠƒAƒjƒŠƒ“/ƒ|ƒŠƒrƒjƒ‹ƒAƒ‹ƒR[ƒ‹•¡‡–Œ‚ÌŠ£Ž¼‰ž“š‚Æ‚»‚Ì‹¤‘¶ƒKƒX‚É‚æ‚é‰e‹¿

Ë–ì‹M”VA’Ŗ؁@OA’†ŽR‰ë°A¬‘q‹»‘¾˜Y

ŽRŒû‘åH

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.

ƒvƒ‰ƒYƒ}—L‹@”––Œ‚ð”í•¢‚µ‚½ QCMƒZƒ“ƒT‚É‚æ‚鍁‚蕪Žq‚Ì”÷—ÊŒŸo‚¨‚æ‚ÑŽ¯•Ê


‰Í¼“Þ•ÛŽqA™–{Šâ—YA’†‘º‰ë”V

NTT“üo—̓VƒXƒeƒ€Œ¤‹†Š

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Ey‘f—ݐϖŒ‚ð—p‚¢‚½y‘fƒZƒ“ƒT[

¬—Ñ—R‰ÀAˆÀÄ‡ˆê

“Œ–k‘å–ò

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.

‘Ï”M«y‘f‚ð—p‚¢‚½ŠeŽí ISFETŒ^“œ—ÞƒZƒ“ƒT‚̍\’z‚Æ“Á«

Â–؈êmAÎŠÛ—Y‘åA”Ñ“c•—g

é‹Ê‘åŠwHŠw•”

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.

ƒ|ƒŠƒAƒjƒŠƒ“‚É‚æ‚éŒÅ’艻y‘f‚ð—˜—p‚µ‚½lHäX‘Ÿ—pƒOƒ‹ƒR[ƒXƒZƒ“ƒT

’r“cÍˆê˜YAã—Ñ‹M—mA“¾–쏇ˆêAH“¡”äŒË”üAˆÉ“¡ŸŠî*A‚–Ø O*

–¼H‘åE–¼‘åˆã*

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.

¶‘Ì“K‡«‚ð—L‚·‚éƒ|ƒŠƒsƒ[ƒ‹‚ð•ïŠ‡Þ—¿‚É—p‚¢‚½y‘fŒÅ’è“d‹É‚̍쐻‚¨‚æ‚Ñ‚»‚̃Zƒ“ƒT“Á«

ˆÀàVŠ²lA¼–Ø ’AŽOˆä ŒõAž­@ÍA’‡–î’‰—Y*

“¿“‡‘åHEãŽs‘åH*

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.

ƒ|ƒŠƒEƒŒƒ^ƒ“‚ð•ïŠ‡Þ—¿‚É—p‚¢‚½y‘fƒZƒ“ƒT‚ÌŠJ”­


ˆÀàVŠ²l, ’·’Jì”ü”¿, ž­@Í, ’‡–î’‰—Y*

“¿“‡‘åHEãŽs‘åH*

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.

ƒAƒjƒIƒ“«“±“d«‚•ªŽq‚ð—p‚¢‚½ƒyƒ‹ƒIƒLƒVƒ_[ƒ[“d‹É

—§ŠÔ@“OA¬ì‚ŽjA¬ŽR@¸

“Œ‹ž”_H‘åH

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.

“d‰ðd‡‚•ªŽqCü“d‹É‚É‚æ‚éV‹KƒOƒ‹ƒR[ƒXƒZƒ“ƒT[

‘·@—§Œ«Aœ@䎁A‰ª“c@’BO

•¨Ž¿HŠwH‹Æ‹ZpŒ¤‹†Š

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 (‡U), (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.

e–û«ƒƒfƒBƒG[ƒ^[‚ð—p‚¢‚½ƒJ[ƒ{ƒ“ƒy[ƒXƒg^ƒAƒ‹ƒR[ƒ‹ƒfƒqƒhƒƒQƒi[ƒ[“d‹É ‚̍쐻

›L@°C–‘ˆêC…’J•¶—Y

¶–½HŠwH‹Æ‹ZpŒ¤‹†Š

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-ƒÀ -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.

“d‹É^ƒ|ƒŠƒCƒIƒ“ƒRƒ“ƒvƒŒƒbƒNƒX–Œ^NADHŽ_‰»y‘f–Œ‚̍\¬‚ÌNADHƒZƒ“ƒT

…’J•¶—YC²“¡@‰C•½“c–FŽ÷C–‘ˆê

¶–½HŠwH‹Æ‹ZpŒ¤‹†Š

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.

¶‘Ì‹@”\“d‹ÉŠE–ʂ̍\’z‚ƃZƒ“ƒVƒ“ƒO

’JŒû@Œ÷

ŒF–{‘åH

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.

ƒAƒ“ƒ‚ƒjƒA‚¨‚æ‚уzƒ‹ƒ€ƒAƒ‹ƒfƒqƒh‚ɑ΂·‚éŠÏ—tA•¨‚̉ž“š“Á«

¬–쎛 •CL—Ñ –ÎŽ÷C–Ø‘º t•FC‘å–÷ ‘½‰ÂŽu*

‹à‘ò‘åHC‹à‘òŒoÏ‘åŒoÏ*

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.

ƒ‰ƒWƒJƒ‹ƒXƒJƒxƒ“ƒWƒƒ[‚ð—p‚¢‚½ in situ NOƒZƒ“ƒT‚̍\’z

‹TˆäŒªˆê˜YAtŽR“N–çA–ö“c•ÛŽqA¬”©‰p—A‘ŠàV‰v’j

“ŒH‘åE¶–½—H

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 NO2-, most probably due to negatively charged layer of PTIO and Nafion. The PTIO immobilized electrode could determine NO concentration range from 0.2ƒÊM to 3ƒÊM in aqueous solution.

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40.

”÷¶•¨”­Œõ‚ð—˜—p‚µ‚½ŠÂ‹«ƒ‚ƒjƒ^ƒŠƒ“ƒOƒVƒXƒeƒ€‚ÌŠJ”­

‘º‹´•äC–kì@Œ\**C¼ˆä’¨lC‹{–{³‹K*CãŒû—˜•¶**C‘ºã—T“ñ**C‰¡ŽRŒ›“ñ**C–¯’J‰hˆê**

iŠ”jƒCƒVƒƒbƒNƒXEÎìŒ§H‹ÆŽŽŒ±ê*E–k—¤æ’[‰È‹Z‘å**

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.

ƒoƒCƒIƒZƒ“ƒT‚ƃCƒIƒ“ƒZƒ“ƒT‚̃tƒ…[ƒWƒ‡ƒ“ƒVƒXƒeƒ€‚É‚æ‚éZ“§ˆ³‚Ì•]‰¿

‹kˆŸŽ÷*AŠOŽRŽ A‹g“c‘וF*A’ôŽR‹`l

‘—§ƒŠƒnƒrƒŠŒ¤A“Œ—m‘åH*

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.
ƒ®à1.86~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.

”÷¬‰t—Œ^‹â^‰–‰»‹âŽQÆ“d‹É‚Æ3“d‹ÉŒn‚Ì‚Pƒ`ƒbƒvã‚ւ̏WÏ‰»

—é–Ø”ŽÍA•½ì‘åŽuA²X–Øãà*AŒy•”ª•v*

’}”g‘啨Ž¿HE“Œ‘åæ’[Œ¤*

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–@‚ð—p‚¢‚½V‚µ‚¢ƒRƒŠƒ“ƒGƒXƒeƒ‰[ƒ[ŒÅ’艻ƒoƒCƒIƒZƒ“ƒT

O.V. Fedosseeva, “à“cG˜aAŸ•”º–¾AÎŠÛ—Y‘åA”Ñ“c•—g

é‹Ê‘åH

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.

•\–ʃvƒ‰ƒYƒ‚ƒ“‹¤–ÂŒ»Û‚ð—˜—p‚µ‚½‰»ŠwƒZƒ“ƒT

“ìŒËGmA‰HŒ´³HA“°ã’·‘¥AŒüˆä’BÆA‘–ì@‰p“ñA‹àŒ´@âêA“›Œû‘P‰›*

‹à‘òH‹Æ‘åŠw‚“xÞ—¿Œ¤‹†ŠJ”­ƒZƒ“ƒ^[AÎìŒ§HŽŽ*

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.

•ªŽqÏ‘w–@‚É‚æ‚é•\–ʃvƒ‰ƒYƒ‚ƒ“‹¤–iSPRj‚̐M†‘•

¼‘º ’mWAˆê“ñŽO Œb”üA´… _•ãA‰F“c ‘׎O

L“‡Œ§—§‘吶•¨Ž‘Œ¹

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Ž, 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–ƉuƒZƒ“ƒT\’z‚Ì‚½‚߂̍R‘̌Œ艻–@‚ÌŒŸ“¢‚ƏWÏ‰»‚ÌŽŽ‚Ý

—é–ؐ³NAX@—Iå

‹ãBH‘åî•ñH

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.

‹à”––Œ•\–ʍ‚•ªŽq‘w‚̍œKÝŒv‚Æ SPRƒZƒ“ƒT‚̍‚Š´“x‰»

“ŒŠC—ѐ’*AŠOŽRŽ A‹g“c‘וF*A’ôŽR‹`l

‘—§ƒŠƒnƒrƒŠŒ¤A“Œ—m‘åH*

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 ƒÊg/ml level.

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