Vol. 10, Supplement A (1994)

Proceedings of the 18th Chemical Sensor Symposium

April 3-5, 1994
Tohoku University

Abstracts

1
ö’…WO3”––Œ‚ÌŠ´ƒKƒX“Á«

 ’†ž^“ñAŒbŒ´‹MŽuAŽR–{’B•v

ΊªêC‘å—H

GAS SENSING CHARACTERISTICS OF WO3 THIN FILM PREPARED BY VACUUM EVAPORATION

Shinji NAKAGOMI , Takashi EHARA and Tatsuo YAMAMOTO

School of Science and Engineering, Ishinonaki Senshu University
Minamisakai, Ishinomaki-shi, Miyagi 986, Japan

The gas sensing characteristics of WO3 film evaporated onto inter digital Pt electrode was studied. The electrical resistance of the WO3 element decreased monotonously with increasing in relative humidity at room temperature. On the other hand, the resistance of WO3 element was measured in some atmosphere, such as N2, O2, H2 and 1000@ppm NO2 in N2, as a function of temperature. It was found that to keep the element at higher temperature improve the NO2 sensitivity. Moreover, in condition of higher temperature, the obstructive effect of O2 gas to NO2 sensitivity of the WO3 element became smaller.


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2
ƒXƒsƒlƒ‹Œ^•¡‡Ž_‰»•¨‚Ì“ñŽ_‰»’‚‘fŒŸ’m“Á«

 š ŽŸ^•ãA¼“ˆ–ÎŒ›A¬—ÑŒ’‹g˜YA‰ª“cŒ³ŽŸ

ˆ¤•Q‘åH

NO2 SENSING PROPERTIES OF COMPLEX OXIDES WITH SPINEL STRUCTURE

Shinsuke KUNITSUGU, Shigenori MATSUSHIMA, Kenkichiro KOBAYASHI and Genji OKADA

Department of Applied Chemistry, Faculty of Engineering, Ehime University
3-Bunkyo-cho, Matsuyama-shi 790, Japan

NO2 sensing properties of thick Zn2SnO4 films have been investigated. Thick Zn2SnO4 films consist of the aggregated Zn2SnO4 particles which are sparsely filled. This suggests that necks between Zn2SnO4 aggregates are scarcely grown. The electric resistance in air monotonously decreases with increasing a temperature, while the resistance in NO2 remarkably increases in comparison with that in air. High NO2 sensitivities (>100) of the thick film are obtained at temperatures of 300 to 400Ž.


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3
BaO2‚ð—p‚¢‚½”¼“±‘Ì‘fŽq‚Ì‚‰·‚Å‚ÌNOxŒŸ’m“Á«

 “¡ˆä“N•vA‹Ê’u@ƒAŽO‰Y‘¥—YAŽR“Y@úf

‹ã‘呇—H

NOx SENSING PROPERTIES OF SEMICONDUCTOR SENSOR ELEMENT USING BaO2 AT ELEVATED TEMPERATURES

Tetsuo FUJII, Jun TAMAKI, Norio MIURA and Noboru YAMAZOE

Department of Materials Science and Technology, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816, Japan

A semiconductor sensor element using BaO2 was found to respond to NO as well as NO2 existing in air at elevated temperatures. The BaO2 sensor showed the moderate sensitivity of ca. 16 to both 100 ppm NO and 100 ppm NO2 at 550Ž, with the 90% response- and recovery-times of 30 s and 3 min, respectively. The sensitivity increased linearly with increasing NOx concentration in the range of 20-200 ppm. TPD experiments revealed that NO was adsorbed on and desorbed from BaO2 around 500Ž reversibly, while NO2 could be adsorbed similarly but was desorbed as NO.


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4
ƒXƒJƒ“ƒWƒEƒ€‚ð“Y‰Á‚µ‚½ƒjƒbƒPƒ‹|“ºŒnŽ_‰»•¨”––Œ‚ÌNOxŒŸo“Á«

 â–ì@WA¡’†MlA‘«—§‹á–ç

ã‘åH

THE NOx SENSING CHARACTERISTICS OF SCANDIUM-DOPED NICKEL COPPER OXIDE THIN FILMS

Susumu BANNO, Nobuhito IMANAKA and Gin-ya ADACHI

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

The thin films of scandium-doped nickel copper oxide were prepared by the RF magnetron sputtering method and then sensing characteristics for both NO2 and NO were investigated. Electrical resistivities of the film increases with increase in concentration of NO while decreases with concentration of NO2.


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5
”––ŒŒ^”¼“±‘ÌŽ®ƒIƒ]ƒ“ƒZƒ“ƒT‚ð—p‚¢‚½—n‘¶ƒIƒ]ƒ“‚Ì‘ª’è

 ’O㔎‰ëAÄ“¡’B•vA‚“c@‹`AŒ´“cŒ’Ž¡*

VƒRƒXƒ‚ƒX“d‹@A•xŽm“d‹@*

AQUEOUS OZONE DETECTOR USING In2O3, THIN FILM SEMICONDUCTOR OZONE GAS SENSOR

Hiromasa TANJYO, Tatsuo SAITO, Tadashi TAKADA and Kenji HARADA*

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

*Fuji Electric Co., Ltd.
1 Fuji-machi, Hino-city, Tokyo 191, Japan

A detector without any reagent, for the continuous determination of a trace amount of aqueous ozone, utilizing an ozone extraction process from water into the gas phase and an In2O3 thin film semiconductor ozone gas sensor, has been developed. It had many advantages including high sensitivity to aqueous ozone and high aqueous ozone selectivity in the presence of various kinds of interfering compounds in water. It was able to detect 0.5 ppb aqueous ozone with a sufficient response. A response to 1 ppm hypochlorous acid HCIO was smaller than that to 10 ppb aqueous ozone. It was revealed that the high sensitivity and the high selectivity were generated considerably in the process of ozone extraction from water into the gas phase. The indication of this detector was somewhat affected by a change in water temperature. A correction process using water temperature was studied. It was clarified that it was caused by the water temperature dependence of the ozone extraction rate and the absolute humidity dependence of the semiconductor gas sensor. A precise determination of the aqueous ozone was performed in the water temperature range from 0 to 40Ž with an improved detector with the correction process by water temperature.


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6
”––ŒƒIƒ]ƒ“ƒZƒ“ƒT

 ŽR“c@–õA‘‰ª—D”üA²Ž¡Œ[ŽsA‚‹´‰pºA•ºŒÉ@—²*AˆÀ–ìŒöŽ¡*

–L“c’†Œ¤A–L“cŽ©“®D‹@*

THIN FILM OZONE SENSOR

Yasushi YAMADA, Yumi MASUOKA, Keiichi SAJI, Hideaki TAKAHASHI, Takashi HYOGO* and Kimiharu YASUNO*

Toyota Central R&D Labs. Inc.,
41-1 Yokomichi, Nagakute, Nagakute-cho, Aichi-gun, Aichi 480-11, Japan

*R&D Center, Toyoda Automatic Loom Works
2-1 Toyoda-cho, Kariya-shi, Aichi 448, Japan

Response characteristics of an ozone sensor comprising thin film indium oxide has been investigated by four-electrode method. The sensor resistance between the platinum electrode and gold electrode responded fast with a high sensitivity for an ozone concentration of 1 ppm in air. However, the recovery response after the ozone exposure became longer after a few hundreds hours operation in air. On the other hand, the recovery response of the sensor resistance between the two gold electrodes was much faster than that between the platinum and gold electrodes after the long term operation. From the results, it is considered that platinum electrodes adsorb ozone or its related reactant species stronger than gold electrodes and therefore the sensor with gold electrodes has fast response and long term stability.


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7
Au-La2O3/SnO2ŒnCOƒZƒ“ƒT

 •Ÿˆä@´A’†ª³“T

VƒRƒXƒ‚ƒX“d‹@

CO GAS SENSOR BASED ON Au-La2O3 LOADED SnO2 CERAMIC

Kiyoshi FUKUI and Masanori NAKANE

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

New composite effects of Au and La2O3 and/or Y2O3 were examined: (1) La2O3 addition effect: characterization of tin oxide surface, thereby a stabilization of the surface oxygen (eg., O2-) and decrease in the number and/or the strength of Lewis acid sites (eg., Sn4+), which are supposed to be active sites of adsorption or oxidation, resulting in reduction of the sensitivity to CO, H2, CH4 and i-C4H10; (2) Au addition effect: selective sensitization( activation )to CO; the other precious metals or metal oxides increased the sensitivity not only to CO, but also to H2 and iso-C4H10. The special effect of Au will be due to its selective adsorption for CO and the absence of active oxygens on the surface of the Au-grains. The present surface chemical reactions causing the sensitivity to CO is supposed to occur in the grain boundary consists of the three grains of tin oxide, lanthanum oxide and gold. The above composite effects were, thus, able to cause successfully the activation to CO inherent in gold at a comparatively high temperature region (eg., 360Ž); and will make it possible to detect CO selectively and stably without the periodic purging at a high temperature.


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8
‘½‘w\‘¢CO‘I‘ð«ƒZƒ“ƒT

 ŽO‹´O˜aA•Ÿˆä@´A’†ª³“T

VƒRƒXƒ‚ƒX“d‹@

MULTI-LAYER STRUCTURE CO SELECTIVE GAS SENSOR

Hirokazu MITSUHASHI, Kiyoshi FUKUI and Masanori NAKANE

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

In the previous work, it has been already reported that CO selectivity to H2 was obtained by addition of BaO to tin oxide semiconductor. However, the sensor had a sevious problem from practical point of view, such as high sensitivity to ethanol. In the present work, the problem was removed by a three-layer structure: first, Cr2O3-SnO2 catalyst layer was formed over the sensing layer of BaO-SnO2 to reduce the sensitivity to H2. Next, WO3-Al2O3 catalyst layer was formed outermost to reduce the sensitivity to ethanol. The sensor thus obtained had a high selectivity to CO even at a high temperature of about 400Ž, and also a quick response to CO. The sensitivity to CO of 50ppm was higher than that to H2, CH4 and ethanol of 1000ppm at 380Ž. The long term stability and the selectivity to CO had been confirmed over one year.


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9
ƒ¿]Fe2O3-CuFe2O4-CuO”––Œ‚̃KƒXŠ´“x“Á«

 ’†¼”Ž”üA•½’ËM”VA“à“cG˜aAŸ•”º–¾

鉤‘å—H

GAS SENSING CHARACTERISTICS OF ƒ¿-Fe2O3-CuFe2O4-CuO THIN FILMS

Hiromi NAKANISHI, Nobuyuki HIRATSUKA, Hidekazu UCHIDA and Teruaki KATSUBE

Graduate school of Science and Engineering, Saitama University
Urawa, Saitama 338, Japan

Gas sensing characteristics of ƒ¿-Fe2O3 thin films doped with copper ions were investigated. The composited and bilayered oxide films containing Fe ions and Cu ions were fabricated by the evaporation method. The composited film in the molar ratio of Cu/Fe=0.2 annealed between 400Ž and 500Ž after deposition of Fe and Cu at the same time consisted of ƒ¿-Fe2O3 and dispersed CuFe2O4 particles. The sensitivity of the film increased to i-C4H10 compared with those of ƒ¿-Fe2O3 film and CuFe2O4 film. The bilayered film with the radio of Cu/Fe=0.1 which was successively deposited by Fe and Cu and then annealed consisted of CuF2O4 thin layer on ƒ¿-Fe2O3 film. The sensitivity of the film also increased. The binding energy of Fe2p and Cu2p electrons of the thin films coexisted with ƒ¿-Fe2O3 and CuFe2O4, had different from those of each single phase film. Above-mentioned difference appears to contribute to the improvement of sensitivities.


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10
SnO2Œú–ŒŒ^“õ‚¢ƒZƒ“ƒTƒw‚ÌŠeŽí‹à‘®Ž_‰»•¨‚̃R[ƒeƒBƒ“ƒOŒø‰Ê

 —é–ØŒ’ŒáA‚“c@‹`

VƒRƒXƒ‚ƒX“d‹@

Various metal oxides coating effects on SnO2 thick film type odor sensors.

Kengo SUZUKI and Tadashi TAKADA

New Cosmos Electric Co., Ltd.
Mituya-naka, Yodogawa-ku, Osaka-city, Japan

To improve the sensitivity to odor and the odor selectivity, The calcination temperature was examined on SnO2 thick films. The sensitivity and the selectivity depended strongly on the calcination temperature. and the optimum temperature for the odor sensor was 1200Ž. The odor selectivity to odorless gases was improved by Pb-addition to SnO2 thick film calcinated at 1200Ž. The effects of various metal oxides coating layers on Pb-added SnO2 thick films also were examined. The layers were effective in characterization of each odor sensors. It seemed that the metal oxide functioned as a filter through the coating layer and as a catalyst at the interface to the films. The present group of sensors might facilitate the construction of odor an discrimination system utilizing different odor selectivities for plural sensors.


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11
‚Š´“xƒWƒƒ`ƒ‹ƒAƒ~ƒ“ƒZƒ“ƒT‚ÌŠJ”­‚Æ‚»‚ÌŒŸ’m‹@\‚̉ð–¾

 ‰ÍŒû’q”ŽA’†¼‰ë•FA‚”ö—Y“ñA´…N”ŽA]“ª@½

’·è‘åH

DEVELOPMENT OF A SEMICONDUCTOR DIMETHYLAMINE GAS SENSOR AND ELUCIDATION OF THE SENSING MECHANISM

Tomohiro KAWAGUCHI, Masahiko NAKANISHI, Yuji TAKAO, Yasuhiro SHIMIZU and Makoto EGASHIRA

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

Trimethylamine and dimethylamine gas sensing properties of In2O3-MgO(5 mol%)-based sensors have been investigated in air and in nitrogen atmosphere. The sensors loaded with Au were more sensitive to TMA than DMA. As for the sensors loaded with Pd, TMA sensitivity was almost comparable to DMA sensitivity. In the case of the sensors loaded with Pt, unique sensing properties were observed at loading amounts of Pt higher than 1.5 wt% : the maximum TMA sensitivity was achieved around 500Ž, whereas the maximum DMA sensitivity around 300Ž. From the DMA and TMA sensing properties of the sensors in nitrogen atmosphere, the presence of negatively charged chemisorbed species other than oxygen adsorbates in TMA atmosphere, is suggested to 'be responsible for the lower TMA sensitivity than the DMA sensitivity at 300Ž.


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12
SnO2ŒnƒoƒŠƒXƒ^‘fŽq‚Ì컂Ƃ»‚̃KƒXŒŸo“Á«

 •ŸŽR—mˆêA‚”ö—Y“ñA´…N”ŽA]“ª@½

’·è‘åH

PREPARATION AND H2 SENSING PROPERTIES OF SnO2, VARISTOR GAS SENSORS

Youichi FUKUYAMA, Yuji TAKAO, Yasuhiro SHIMIZU and Makoto EGASHIRA

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

Current(I)-voltage(V) characteristics of SnO2-based specimens have been investigated in air as well as in 1% H2. Tin dioxide itself exhibited a nonlinear I-V characteristic at temperatures less than 500Ž and a shift in breakdown voltage to a lower electric field in the presence of H2. Addition of 1 mol% Bi2O3 to SnO2 led to an increase in H2 sensitivity, but resulted in a shift in breakdown voltage to a higher electric field in air. Further addition of Bi2O3 led to a decrease in H2 sensitivity and to an increase in breakdown voltage. Simultaneous addition of 1 mol% Bi2O3 and 1 mol% Sb2O3 was effective for decreasing the breakdown voltage, but resulted in a poor nonlinear I-V characteristic and lower H2 sensitivity. Among the specimens tested, the highest H2 Sensitivity was achieved with the SnO2 varistor doped with 1.0 mol% Bi2O3.


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“Á•Êu‰‰‚P
ƒKƒXƒZƒ“ƒT‚Ì‚½‚߂̃yƒƒuƒXƒJƒCƒgŒ^

Ž_‰»•¨”¼“±‘̂ƃAƒ‹ƒJƒŠƒCƒIƒ““±“d‘Ì‚Ì’²»

 ’艪–F•F

ˆ¤ŠÉ‘åH

PREPARATION OF SEMICONDUCTIVE PEROVSKITE-TYPE OXIDES AND ALKALI ION CONDUCTORS FOR GAS SENSORS

Yoshihiko SADAOKA

Department of Applied Chemistry, Faculty of Engineering. Ehime University
Matsuyama 790, Japan

To develop gas sensors, the selection and/or the preparation of functional materials are important questions. We are studying some types of gas sensors for quantification of NH3, NO2, CO2 and/or humidity by using organic and inorganic materials. Recently, some inorganic materials have been examined for application to NO2 and CO2 gas sensor. The results of these studies will be presented.


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13
‰ßŽ_‰»ƒ|ƒŠŽ_‚©‚燬‚³‚ê‚éƒ^ƒ“ƒOƒXƒeƒ“ƒ“ƒuƒƒ“ƒY‚É‚æ‚鎼“xƒZƒ“ƒT

 ˜I–{ˆÉ²’jAŠÝ–{@ºAH“¡“Oˆê

“Œ‘嶌¤

HUMIDITY SENSOR USING TUNGSTEN BRONZE SYNTHESIZED FROM PEROXO-POLYTUNGSTIC ACID

Isao TSUYUMOTO, Akira KISHIMOTO and Tetsuichi KUDO

Institute of Industrial Science, University of Tokyo
Roppongi 7-22-1, Minato-ku, Tokyo 106, Japan

Hexagonal potassium tungsten bronze (K-HTB) synthesized through new synthetic route at low temperature (500Ž) increases remarkably in resistivity in a humid atmosphere at room temperature. Conductometry and gravimetry performed in various humidities (PH2O) showed that the saturated values of resistivity and of water-intake are clear functions of PH2O. XRD study revealed that lattice parameters of K-HTB are changed by water-intake. The mechanism of resistivity change with humidity will be discussed in this connection.


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14
Œõd‡‚É‚æ‚è컂µ‚½‰Ë‹´‚•ªŽq–Œ‚ð—p‚¢‚½—e—ÊŒ^Ž¼“xƒZƒ“ƒT

 V–{ªŽjA¼Œû³MA’艪–F•FAŽðˆä‹`˜Y

ˆ¤•Q‘åH

CAPACITIVE-TYPE HUMIDITY SENSOR USING CLOSSLINKED POLYMER FILM PREPARED BY PHOTOIRRADIATION

Masafumi SHINMOTO, Masanobu MATSUGUCHI, Yoshihiko SADAOKA and Yoshiro SAKAI

Department of Applied Chemistry, Faculty of Engineering, Ehime University
Matsuyama, Ehime 790, Japan

Capacitive-type humidity sensor was prepared using poly(vinyl cinnamate) that was known as one of the most common photopolymer. The polymer is hydrophobic. The dimerization of the polymer occurs between cinnamoyl groups by photoirradiation resulting in the crosslinked structure. Since irradiation time influences on the degree of crosslinking, the effect of irradiation time on the sensing characteristics were examined. The prepared sensor had good sensitivity and good durability against various alcohols and acetone vapor compared with the previous one which. was prepared by using poly(vinyl esters) crosslinked by heat treatment. The present sensor was proved to be a practical humidity sensor.


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15
‚‰·Œ^ƒvƒƒgƒ““±“d‘Ì‚ð—p‚¢‚½‹N“d—ÍŽ®’Y‰»…‘fƒZƒ“ƒT

 “ú”ä–ì‚ŽmAò–ØH•FAŠâŒ´Oˆç

–¼‘åH

GALVANIC CELL TYPE HYDROCARBON SENSOR USING A HIGH TEMPERATURE-TYPE PROTONIC CONDUCTOR

Takashi HIBINO, Akihiko MASEGI and Hiroyasu IWAHARA

Synthetic Crystal Research Laboratory, School of Engineering, Nagoya University
Chikusa-ku, Furo-cho, Nagoya 464, Japan

A galvanic cell type hydrocarbon sensor without a standard electrode material has been fabricated using the high temperature-type protonic conductor as a solid electrolyte. The test cell, Pd | CaZr0.9In0.1O3-ƒ¿ | Au, gave the stable EMF for hydrocarbons (CH4, C2H6 or C3H8) in air at 700Ž. The 90 % response time was less than 10 s, and the relationship between the EMF and the hydrocarbon content was almost linear. The sensing mechanism was based on the steam concentration cell, which resulted from the difference in combustion activity for hydrocarbons between two electrode materials.


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16
‰–‰»ƒoƒŠƒEƒ€ŒnŒÅ‘Ì“d‰ðŽ¿‚ð—p‚¢‚½‰–‘fƒKƒXƒZƒ“ƒT‚Ì’á”Z“xˆæ‚ł̉ž“š

 –ìG’ÊA™–{žÄ—CAX@–FH*A‰ª“‡–õO*

V‹•l‚êAZ—F‹à‘®zŽR*

ELECTROMOTIVE FORCE RESPONCES AT LOW CONCENTRATION REGION FOR Cl2 GAS SENSOR USING BaCl2-KCl SOLID ELETCTROLYTE

Hiromichi AONO, Eisuke SUGIMOTO, Yoshiaki MORl* and Yasuhiro OKAJIMA*

Department of Industrial Chemistry, Niihama National College of Technology
7-1 Yagumo-cho, Niihama, Ehime 792, Japan

*Niihama Research Laboratory, Sumitomo Metal Mining Company, Limited
3-5-3 Nishibara-cho, Niihama, Ehime 792, Japan

A C12 gas sensor using 0.97BaC12-0.03KCl solid electrolyte was investigated at low C12 concentration region. The response time for the sensor using a RuO2 powder as a measuring electrode was faster than that using a RuO2 paste. Good agreement between the measured and the calculated electromotive force (EMF) values was obtained for above 2 ppm Cl2 gas. The EMF was influenced by O2 gas concentration when C12 gas concentration is smaller than 2 ppm.


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17
ˆŸÉŽ_ƒiƒgƒŠƒEƒ€Œn•â•‘Š‚ð—p‚¢‚½ŒÅ‘Ì“d‰ðŽ¿NOxƒZƒ“ƒTi‹¤‘¶ƒKƒX‚̉e‹¿j

 ’†•½‹M”NA‰|–{@—ÊA£ŒËŒû“N•vA“cŒû”ŽK*AÎŒ´i‰î*AŽO‰Y‘¥—Y**AŽR“Y@úf*

‘åãƒKƒXA‹ž“s“dŽqH‹Æ*A‹ã‘呇—H*

SOLID ELECROTLYTE NOx SENSOR USING SODIUM NITRITE-BASED AUXILIARY PHASE (EFFECT OF COEXISTENT GASES)

Takatoshi NAKAHIRA, Hakaru ENOMOTO, Tetsuo SETOGUCHI, Hiroyuki TAGUCHI, Shinsuke ISHIHARA, Norio MIURA and Noboru YAMAZOE

Research and Development Center, Osaka Gas Co., Ltd.
Konohana-ku, Osaka 554, Japan

*Kyushu Laboratory, Kyoto Electronics Manufacturing Co., Ltd.
Kitakyushu-shi, Fukuoka 804, Japan

**Department of Materials Science and Technology, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816, Japan



An Na+-conductor(NASICON)-based solid electrolyte sensor fitted with an NaNO2-LI2CO3 (9:1 in molar ratio. ) auxiliary phase showed excellent sensing characteristics against NO2 in the range of 1 to 100 ppm. The sensor was combined with NO/NO2 converting catalyst to detect both NO2 and NO. This combined sensor system was found to have linear sensing characteristics for less than 100 ppm of NOx in the coexistence of gases such as CO2, H2O and H2.


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18
Ž_‘fƒCƒIƒ““`“±«ŒÅ‘Ì“d‰ðŽ¿‚ð—p‚¢‚½NOxƒZƒ“ƒT

 •àVGs*AŒµ@‰i“SAŽO‰Y‘¥—YAŽR“Y@úf

ƒŠƒPƒ“*A‹ã‘呇—H

SOLID ELECTROLYTE NOx SENSOR USING OXIDE ION CONDUCTOR

Hideyuki KUROSAWA*, Yongtie YAN, Norio MIURA and Noboru YAMAZOE

*Riken Corporation
4-14-1 Suehiro, Kumagaya-shi, Saitama 360, Japan

Department of Materials Science and Technology, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816, Japan

A potentiometric solid-state electrochemical NOx sensor device was fabricated by combining an MgO-stabilized zirconia (oxide ion conductor) tube with a Ba(NO3)2-based auxiliary phase. The use of a binary system of Ba(NO3)2-CaCO3 was found to give fairly good sensing characteristics to both NO2 and NO at 450Ž, following Nernst's equation. It is noteworthy that the improvement of NO sensitivity can be attained with the present sensor. The 90% response times of the sensor to 100 ppm NO2 and 500 ppm NO were as short as 30 s at 450Ž. In order to reduce the influence of O2 concentration on NO2 response, a planar type sensor device was newly designed and tested.


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19
ƒAƒ‹ƒJƒŠ‹à‘®’YŽ_‰–|ƒAƒ‹ƒ~ƒiŒnÄŒ‹‘ÌCO2ƒZƒ“ƒT[‚Ì’á”Z“x“Á«

 VŠÖ—Ç•vAm‰È’C•v*A“à“c@—E*

“Œ–kH‘åA“Œ–k‘åH*

SENSING PROPERTIES OF CO2 SENSOR CONTAINING SINTERED MIXTURES OF ALKALI METAL CARBONATES AND ALUMINA AS AN ELECTROLYTE FOR LOW CO2, CONCENTRATIONS

Yoshio NIIZEKl, Tatsuo NISHINA and Isamu UCHIDA

Department of Science, Tohoku Institute of Technology
Yagiyama, Taihaku-ku, Sendai 982, Japan

Department of Technology, Tohoku University
Aramaki, Aoba-ku, Sendai 980, Japan

A galvanic cell type carbon dioxide sensor which operates in the temperature region of 350 to 420Ž was constructed using gold mesh electrodes and a sintered electrolyte consisting of alkali carbonates(Li2CO3, Na2CO3, and K2CO3)and alumina. The sensor using the air passed through a soda lime tube as a standard gas and, outdoor air as a sensing gas showed very stable EMF and a maximum value in the temperature region of 380}20Ž. The relation between EMF and logarithmus of carbon dioxide partial pressure was linear over the concentration range of 50 to 750 ppm of carbon dioxide. The EMF was dependent on partial pressures of unsaturated hydrocarbon gases.


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20
Na2CO3‚ð—p‚¢‚½CO2ƒKƒXƒZƒ“ƒT‚̉ž“š«

 ƒAƒ“ƒhƒŒƒAƒXEƒfƒ…ƒxA’艪–F•FAŽðˆä‹`˜Y

ˆ¤’g‘åH

RESPONSE BEHAVIOR OF CO2 GAS SENSORS BASED ON Na2CO3 SOLID ELECTROLYTES

Andreas DUBBE, Yoshihiko SADAOKA and Yoshiro SAKAI

Department of Applied Chemistry, Faculty of Engineering
Ehime University, Matsuyama 790, Japan

To clarify the role of the electrode-electrolyte interface in solid-electrolyte based CO2 Sensors, sensors made up from Na2CO3/ BaCO3 discs with Au, Pd and Pt electrodes were examined. Both deviations from the theoretical sensitivity and response times were lowest at yttria-doped sensors with Pd-electrodes. Sensitivity to moisture also depends on both electrode and electrolyte material.


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21
NASICON-Na2O/Al2O3/nSiO2•¡‡–Œ/ZrO2‚ÌCO2ƒKƒXƒZƒ“ƒTƒw‚Ì—˜—p

 ’†ŽR@‹*C’艪–F•FAŽðˆä‹`˜YAƒwƒ‹EƒXƒvƒŠƒAƒgƒm

•iì”’—ùŠ¢*Cˆ¤ŠÉ‘åH

PREPARATION OF NASICON-Na2O.Al2O3.nSiO2/ZrO2 AND ITS APPLICATION TO SOLID-STATE ELECTROCHEMICAL CO2 GAS SENSOR

Susumu NAKAYAMA*, Yoshihiko SADAOKA, Yoshiro SAKAI and Heru SUPRlYATNO

*New Materials Research Center, Shinagawa Refractories Co., Ltd.
Bizen 705, Japan

Department of Applied Chemistry, Faculty of Engineering, Ehime University
Matsuyama 790, Japan

As a densed solid state sodium ionic conductor, the composite of sodium aluminosilicate and Na3Zr2Si2PO12 were examined. For the composite sintered at 1050Ž, the electrical properties are mainly based on the Na3Zr2Si2PO12 and the densification is well proceeded. A good junction between the composite and Y-stabilized zirconia was achieved when the sintering was done at 1175Ž or higher. The formation of the zirconia particles in the composite layer resulted in the enhancement of the mechanical strength at the junction. By using the ceramics, a solid state electrochemical CO2 sensor with Na2CO3 layer was fabricated. Whilst the sensitivity to CO2 was slightly influenced by coexistence of water vapour in the test gas, a good sensing characteristic based on a two-electron electrochemical reaction was confirmed.


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22
“±“d«Ž_‰»•¨ŒÅ—n‘ÌiLi“Y‰ÁLa2-XSrxCuO4j‚ðŒÅ‘̊ɂƂµ‚Ä—p‚¢‚½CO2ƒKƒXƒZƒ“ƒT[

 ’£@‰vŽW*A¬“c‰p˜a*A…胈ê˜YA“c씎Í

‰¡•l‘‘åŠÂ‹«Œ¤AŒƒuƒŒ[ƒL’†Œ¤*

CO2 GAS SENSORS USING OXIDE ION-ELECTRON MIXED CONDUCTORS (Li-DOPED La2-xSrxCuO4) AS SOLID REFERENCE ELECTRODES

Zhang Yi Can*, Hidekazu NARITA*, Junichiro MIZUSAKI and Hiroaki TAGAWA

Institute of Environmental Science and Technology, Yokohama National University
156 Tokiwadai, Hodogaya-ku, Yokohama 240, Japan

* Akebono Brake Research and Development Center, Ltd.
4-71 Higashi 5-Chome, Hanyu-shi, Saitama 348, Japan

Solid-state electrochemical CO2 sensors were constructed by incorporating a lithium ion conductor (Li2CO3-5mol%Li3PO4-5mol%Al2O3) with solid reference electrodes of Li-doped oxide ion-electron mixed conductor(La2-xSrxCuO4). The EMF of the cell depends logarithmically on the CO2 partial pressure in CO2/O2 gas mixtures at 350Ž and 400Ž. EMF reached a steady state value with in 1 min at 400Ž. Reproducible responses were obtained during the one -month test in the dry CO2/O2 gas at 400Ž.


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23
ƒŠƒ`ƒEƒ€ƒCƒIƒ““`“±‘ÌAŽ_‰»•¨ƒCƒIƒ““`“±‘̈ê‘ÌŒ^‚Ì’YŽ_ƒKƒXƒZƒ“ƒTƒvƒ[ƒu

 ¡’†MlAœA“c—m•½A‘«—§‹á–ç

ã‘åH

A CARBON DIOXIDE GAS SENSOR PROBE CONSTRUCTED FROM LITHIUM IONIC AND OXIDE IONIC CONDUCTORS

Nobuhito IMANAKA, Yohei HIROTA and Gin-ya ADACHI

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

A carbon dioxide gas sensor probe with a built-in heater was fabricated using the combination of lithium ionic and oxide ionic conductors. There types of oxide ionic conductors, Bi2O3-Y2O3(3:1), CeO2-Gd2O3 (8:1), and ZrO2-Y2O3(9:1)were applied. A zirconia or bismuth oxide based sensor showed an excellent Nernst response. The probe is applicable even on condition that the water vapor exists up to 20 vol % in the ambient atmosphere for CO2 detection higher than 1000 ppm.


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24
MOSFETƒKƒXƒZƒ“ƒT‚Ì”Mˆ—‚ÌŒø‰Ê

 XˆÍ‹±OA‹à@“N*

“Œ‹žƒKƒXAƒtƒ@ƒ“ƒNƒVƒ‡ƒiƒ‹ƒƒWƒbƒN*

THE EFFECT OF THERMAL ANNEAL FOR MOSFET GAS SENSORS

Yasuhiro MORITA and Choi KIM*

Frontier Technology Research Institute, Tokyo Gas Co., Ltd.
7-7 Suehiro-cho, 1-chome, Tsurumi-ku, Yokohama 230, Japan

*Fanctional Logic Corporation
7-16 Roppongi 3-Chome, Minato-ku, Tokyo 106, Japan

This paper discusses the effect of thermal anneal for getting highly sensitive palladium gate MOSFET hydrogen sensors. In these anneals, temperature, hydrogen concentration and time are important parameters. As a result, the low temperature anneal like at one hundred degree Celsius in hydrogen atmosphere is so effective as to get highly sensitive devices and there exists a threshold of concentration in hydrogen anneal. We conclude that an irreversible phenomenon influences Palladium films during this thermal anneal because characteristics of the sensors after this annealing have never returned to initial ones, while the sensors before this anneal don't detect hydrogen sensitively.


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25
’è“dˆÊ“d‰ðŽ®ƒZƒ“ƒT‚É‚æ‚éƒAƒ‹ƒVƒ“AƒVƒ‰ƒ“ƒKƒX‚Ì‘I‘ð“IŒŸo

 Î’n@“OA”Ñ“‡“S–çA‚‹´Ÿ*

—Œ¤ŒvŠíA—‰»ŠwŒ¤‹†Š*

Selective Detection of Arsine and Silane by an Amperometric Gas sensor Using a Gold Thin-Film Electrode

Toru ISHIJI, Tetsuya IIJIMA and Katsuo TAKAHASHI*

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

*The Institute of Physical and Chemical Research (RIKEN)
2-1 Hirosawa, Wako-shi, Saitama 351-01, Japan

Selective detection of arsine and silane was investigated by means of electrochemical gas sensor. The working electrodes of sensors were constructed by a gold thin-film, a platinum thin-film and a platinum black electrode formed on gas permeable membranes. The selectivity for arsine against coexisting gases such as solvent vapor and hydrogen, was superior by the sensor using the gold thin-film electrode (AuTF-sensor) in comparison with that using the platinum one. The AuTF-sensor showed a good linear relationship between the oxidation current and low concentration of arsine gas. These results indicate that the AuTF-sensor can be utilized as more reliable sensor in practical field than ordinary sensor using the platinum black electrode.


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26
“S‚Ì•\–Êó‘Ô‚Ì‘oˆÀ’è«‚ð—p‚¢‚½Ž_‘fƒZƒ“ƒT

 ÎŒ´Œ°ŒõA’©‘qjŽ¡

‰¡•l‘‘åH

APPLICATION OF BISTABLE NATURE OF METAL SURFACE STATES IN AQUEOUS SOLUTION TO A OXYGEN SENSOR

Akimitsu ISHIHAPA and Shukuji ASAKURA

Department of Material Engineering. Faculty of Engineering, Yokohama National University
Yokohama-shi, Kanagawa 240, Japan

Iron and its alloies take two surface states, i.e., the passive and active in some aqueous solutions. These surface states are bistable and sensitively affected by the concentrations of oxidants and pH in solution. Distinctive differences in electrode potential and surface impedance between these two states are expected. Iron (Fe:99.95%) was immersed in various pH buffer solution. Shortly after the change of the atmosphere, the electrode attained either passive or active state depending upon the oxygen concentration of the solution. The potential difference between passive and active states was larger than 550mV. Thus, the measurement of potential provided whether the oxygen concentration was higher or lower than a threshold value. The threshold value could easily be adjusted by changing pH.


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27
ƒfƒoƒ‹ƒ_‡‹à“d‹É‚ð—p‚¢‚½NO3-‚̊ȈՑª’è

 ‰ªèTŽiA’©‘qjŽ¡

‰¡•l‘‘åH

NITRATE SENSITIVE METAL ELECTRODE WITH DEVARDA' S ALLOY

Sinji OKAZAKl and Shukuji ASAKURA

Department of Material Science and Chemical Engineering, Yokohama National University
Hodogaya-ku, Yokohama 240, Japan

The electrode potential of Devarda' s alloy in phosphate solutions buttered at pH=12 containing a different amount of nitrate ions and deaerated with argon was measured. The linear relation between the electrode potential and the concentration of nitrate ions [NO3-] whose slope was about 1.6mV/[NO3-]/mg/l was obtained where [NO3-] was less than 40 mg/l. When [NO3-] was larger than 200 mg/l. log[NO3-] was linearly related to electrode potential with a slope of 120mV/decade up to [NO3-] =10.000 mg/l . The presence of chloride. sulfate and perchlorate ions gave almost no effect on the above relations. The sensitivity and selectivity of the present method exceed those of nitrate ion selective electrode one. Since the electrical impedance of corroding metal l solution interface was much lower than that of the other methods, the potential measurement would be easier.


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28
…»U“®ŽqŽ®ƒKƒXƒZƒ“ƒT‚̉ߓn‰ž“š”gŒ`‚̉ðÍ‚É‚æ‚é‚è‚Ì”»•Ê

 ’Ö–ìŽj˜NA’r“cŽO—YA–k쬎÷A“ìŒËGm

‹à‘òH‘åƒfƒoƒCƒXŒ¤

DISCRIMINATION OF AROMAS BY PATTERN RECOGNITION ANALYSIS OF TRANSIENT RESPONSES MEASURED USING A QUARTZ RESONATOR GAS SENSOR

 Shiro TSUBAKINO, Mitsuo IKEDA, Shigeki KITAGAWA and Hidehito NANTO

Electron Device System Research Laboratory, Kanazawa Institute of Technology
7-1 Oogigaoka, Nonoich-machi, P.O. Kanazawa-South, Ishikava 921, Japan

Transient response curves for exposure to aromas which are generated by vaporizing different kinds of wine are observed using an epoxy-coated quartz-resonator gas sensor. The pattern recognition analysis using neural network is carried out using parameters which characterize the transient response curves. The recognition probability of neural network is 100 [%] for 14 trials as a result of choice of appropriate nine parameters.


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29
ƒ|ƒŠƒsƒ[ƒ‹•ë–Œ‚ð—p‚¢‚½ƒKƒX•ªŽq”FŽ¯ƒZƒ“ƒT‚ÌŠJ”­

 ‘÷ì´”üAŒ÷“‹`lA”d–@—TAŽR‰º˜a’j

L“‡‘呇‰ÈŠw

FABRICATION OF A GAS SENSOR USING A POLY(PYRROLE) THIN FILM FOR DETERMINATION VARIOUS VAPOURS

Kiyomi NIGORIKAWA, Yoshihito KUNUGI. Yutaka HARIMA and Kazuo YAMASHITA

Division of Material and Life Sciences, Faculty of Integrated Arts and Sciences, Hiroshima University,
1-7-1 Kagamiyama, Higashihiroshima 724, Japan

A new type of gas sensor based on simultaneous measurement of mass and resistance changes on a poly (pyrrole) thin film has been described. Using this sensor various vapors such as primary alcohols were analyzed qualitatively as well as quantitatively. Moreover this sensor has been used to study the interaction between the poly(pyrrole) film and vapors and interaction explained by the electron donating or accepting properties of the vapor molecules.


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30
ƒJƒ‹ƒZƒCƒ“|‚•ªŽq•¡‡–Œ‚ð—p‚¢‚½ŒõŠw“IŽ¼“xƒAƒ“ƒ‚ƒjƒAƒZƒ“ƒT

 ’艪–F•FAŽðˆä‹`˜YA‰Í‰z—R”üŽq

ˆ¤•Q‘åH

OPTICAL HUMIDITY AND AMMONIA GAS SENSOR USING CALCEIN BASED FILMS

Yoshihiko SADAOKA, Yoshiro SAKAI and Yumiko KAWAGOE

Department of Applied Chemistry, Faculty of Engineering, Ehime University
Matsuyama 790, Japan

ăMAX of the absorption band of calcein entrapped within a polymer matrix is influenced by the acidity or basicity of the polymer. For poly (ethylene oxide) composite, fluorescence withăMAX= 540 nm is enhanced by the sorption of water. For poly(vinyl pyrrolidone) composite, the optical intensity at 490 nm decreased and at 540 nm increased in the reflection mode with increasing humidity and that at 520 nm decreased with increasing ammonia concentration.


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31
ƒuƒƒ‚ƒNƒŒƒ][ƒ‹ƒp[ƒvƒ‹|‚•ªŽq•¡‡–Œ‚ð—p‚¢‚½ŒõŠw“INH3ƒZƒ“ƒT

 ’艪–F•FAŽðˆä‹`˜YAŽR“c¹OA‹Ê–î—S“ñ

ˆ¤Žö‘åH

OPTICAL AMMONIA GAS SENSORS BY USING BROMOCRESOL PURPLE POLYMER COMPOSITES

Yoshihiko SADAOKA, Yoshiro SAKAI, Masahiro YAMADA and Yuuji TAMAYA

Department of Applied Chemistry, Faculty of Engineering, Ehime University
Matsuyama 790, Japan

Thin films doped with bromocresol purple are applicable for quantification of ammonia concentration in ambient air. The absorbance of covalently bound bromocresol purple to benzylchloride-methymethacrylate copolymer is responsible for the good reversibility and fast response times to changes of ammonia concentration in air. The reversibility and response behaviour is improved by humidification. The absorbance at 600 nm increase with ammonia concentration in air.


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32
H2-ƒeƒgƒ‰ƒtƒFƒjƒ‹ƒ|ƒ‹ƒtƒBƒŠƒ“”––Œ‚ÌŠ´ƒKƒX“Á«

 ŒbŒ´‹MŽuA’†ž^“ñAŽR–{’B•v

ΊªêˆÚ‘å—H

GAS SENSING CHARACTERISTICS OF H2-TETRAPHENYPORPHYRIN THIN FILM.

Takashi EHARA, Shinji NAKAGOMI and Tatsuo YAMAMOTO

Department of Electronic Materials, School of Science and Engineering, Ishinomaki Senshu University
Ishinomaki, Miyagi 986, Japan

Gas sensing characteristics for humidity, NO2 and trimethylamine { N(CH3)3 } of spin coated H2-tetraphenylporphyrin (H2-TPP) thin film were studied by means of capacitance type sensor. H2-TPP thin film spin coated on 40mm pitched interdigital electrode sensed humid air by increase of capacitance with high response speed. Both adsorption and desorption process complete within about 1 second. The film also detected trimethylamine with the concentration of less than 1 ppm efficiently. The capacitance displayed liner dependency on concentration of trimethylamine from 0.1 to 1.0 ppm. However, the film showed poor sensitivity for NO2 that has been target gas for H2-TPP fluorescence quenching type sensor.


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33
Pbƒiƒtƒ^ƒƒVƒAƒ“ö’…–Œ‚̃KƒX’E—£“Á«‚Ì”Mˆ—Œø‰Ê

 ŽR–¼¹’jAŠÛŽR‹P•FA”è®–ç

“Œ‹ž“d‹@‘å

HEAT TREATMENT EFFECTS ON CHARACTERISTICS OF GAS DESORPTION FOR Pb-NAPHTHALOCYANINE EVAPORATED FILMS

Masao YAMANA, Teruhiko MARUYAMA and Naoya KASHIWAZAKI

Department of Science and Engineering, Tokyo Denki University
Hatoyama-machi, Hiki-gun, Saitama 350-03, Japan

The gas characteristics of PbNc evaporated films for NO2 gas are improved by heat treatments in the range 200`250Ž in air for 2h. Repeatable responses are obtained at film temperatures more than the gas desorption peak temperature. The heat treatment induces crystal growth in which an stacking axis is perpendicular to the substrate surface. As a result, adsorption sites might be generated at the grain boundaries.


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34
ƒKƒXƒZƒ“ƒT‚ð—p‚¢‚½lŠÔ‚Ì‚Ó‚é‚Ü‚¢‚Æ‹Gß‚Ì“¯’èƒVƒXƒeƒ€‚ÌŽŽì

 ‘å–÷‘½‰ÂŽuA–Ø‘ºt•F*A¼‰Y‹g“W**AÎ⺓ñ

•xŽR‘Û‘ål•¶A‹à‘ò‘åH*AƒtƒBƒKƒ‹ZŒ¤**

TRIAL MANUFACTURING OF IDENTIFYING SYSTEM FOR HUNAN BEHAVIOR AND SEASONS USING GAS SENSOR

Takashi OYABU, Haruhiko KIMURA*, Yoshinobu MATSUURA** and Shozo ISHIZAKA

Department of Sociology, Toyama University of International Studies
Oyama-cho, Toyama 930-12, Japan

*Department of Electrical and Computer Engineering, Kanazawa University
Kodatsuno, Kanazawa 920, Japan

**Figaro Engineering Inc.
Minoo-shi Osaka 562, Japan

Human behavior and seasons are recognized by a gas-sensor system. Awakening and sleeping are identified as the human behaviors in this system . The recognitions are done by the identifying characters of the daily periodical patterns, which are output from the sensor. The sensor is a type of a tin oxide and has no gas-selectivity. Procedural programming is used in the recognition processes. The patterns descend gradually during sleeping and ascend suddenly as of awakening. The amplitude of the pattern is changed in dependence on seasons. The amplitude in winter is large and small In summer. Descending and ascending characteristics of the pattern can identify the human behaviors and seasons on the measuring day.


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35
Ž©—ãU“®Œ»Û‚ð—p‚¢‚½—¬‘¬‚Ì‘ª’è

 ÎŒ´Œ°ŒõA’©‘qjŽ¡

‰¡•l‘‘åH

A POSSIBLE MOTION SENSOR WITH FREQUENCY OUTPUT

Akimitsu ISHIHARA and Shukuji ASAKURA

Department of Material Engineering, Faculty of Engineering, Yokohama National University
Yokohanla-shi, Kanagawa-ken 240, Japan

Electrochemical oscillations have often been observed in iron immersed in the solution containing phosphoric acid and hydrogen peroxide. This oscillation has been interpreted by the cross linkage between electrochemical reactions and mass transport processes in the vicinity of an electrode. Therefore, the oscillation frequency is expected to reflect the flow rate around the electrode. A rod of carbon steel S50C was mounted in rotating disc apparatus. The intersection of the rod rotated concentrically. In the mixture of 0.5M phospheric acid and 1.5M hydrogen peroxide the highly stable electrochemical oscillation appeared. The amplitude of potential change was about 600mVp-p. The oscillating frequency was a sensitive function of rotation rate in the range of 100 rpm to 2000. It is very possible to develop the motion sensors whose output is frequency by using this phenomenon .


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36
‚Š´“xŒõ“±”g˜H‚ð—˜—p‚µ‚½ƒAƒ“ƒ‚ƒ…ƒAƒZƒ“ƒT‚ÌŠJ”­

 ’Â@‹Å–¯AˆÉ“¡Œö‹IA‘º—ÑáÁsAŒÜ\—’çH*

‰¡•l‘‘åŠÂ‹«Œ¤A‰`Œ´‘Œ¤

AMMONIA GAS SENSOR BASED ON HIGHLY SENSITIVE OPTICAL WAVEGUIDES

Xiao-Min CHEN, Kiminori ITOH, Masayuki MURABAYASHI and Chiaki IGARASHI

Institute of Environmental Science and Technology, Yokohama National University
Tokiwadai, Hodogaya-ku, Yokohama 240, Japan

*Ebara Research Co., Ltd.
2-1 Honfujisawa 4, Fujisawa 251, Japan

We have developed optical waveguides (OWGs) highly sensitive to surface species, and applied them to construction of ammonia gas sensors. The OWGs are composed of a thin OWG having large refractive index (Ag+-doped waveguide layer) embeded into another OWG having low refractive index (K+-doped waveguide layer). A sensitive layer consisting of a polymer and a dye was coated onto the OWGs. The sensor showed reversible responses to the exposure of ammonia vapor in the range of 100 ppb - 10 ppm.


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37
SOIŠî”‚ð—p‚¢‚½•\–ÊŒõ“dˆ³ƒZƒ“ƒT‚ÌŒŸ“¢

 ˆÉ“¡‘PFAÎìF–¾

V“dŒ³

SPV SENSOR with SOI WAFERS

Yoshitaka ITO, Takaaki ISHIKAWA

Research & Development Center, Shindengen
Hanno-shi, Saitama 357, Japan

This paper reports a novel structure and system of surface photovoltage (SPV) chemical sensor and method of illumination at the back of wafer. Devices are made of different thicknesses of wafers, 500ƒÊm Si wafer, 100 and 10ƒÊm with SOI (Silicon on Insulator ) , wafer, 0.6ƒÊm with SOS (Silicon on Sapphire) wafer. The peak value of an a. c. photocurrent using Si, SOI and SOS wafer is obtained at the wavelength of around 1000, 1000 and 550 nm, respectively. The SOS type SPV sensor achieves the back-side illumination with visible light beam, from He-Ne laser or laser diode, for large scale integrated chemical sensor system.


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38
LEDƒAƒŒƒC‚ð—p‚¢‚½SPVƒCƒIƒ“i–¡ŠojƒZƒ“ƒT[

 ‹àˆäN’ÊA²X–Ø@–LA“à“cG˜aAŸ•”º–¾

é‹Ê‘åH

SPV ION (TASTE) SENSOR WITH A LED ARRAY

Yasuyuki KANAI, Yutaka SASAI, Hidekazu UCHIDA and Teruaki KATSUBE

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

The SPV (Surface Photo Voltage) method was applied to a taste sensor by improving the sensitivity and the measurement speed[1] . For the development of the high speed measurement system, an array structure of micro LEDs was fixed under the semiconductor chip and the two dimentional signal was picked up by scanning the LEDs electrically. The sensitivity was improved by using the differential measurement method based on a time sharing process. The improved system made it possible to discriminate sweet substances, which is considered to have a low sensitivity to the conventional sensor.


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39
ƒtƒHƒgƒ_ƒCƒI[ƒh‰»Šw”­ŒõŒŸoŠí]‚e‚h‚`–@‚É‚æ‚éH•i—pƒZƒ“ƒT[‚ÌŠJ”­

 –ö¶“c@ŒOA•ÓŒ©²GAˆÉ“Œ@“NAó–ì‘׈ê

“d‹C‰»ŠwŒvŠí

DEVELOPMENT HIGHIY SENSITIVE CHEMILUMINESCENCE FIA SYSTEM USING PHOTODIODE AS A DETECTOR AND ITS APPLICATION FOR FOOD INDUSTORY

Kaoru YAGIUDA, Akihide HEMMI, Satoshi ITO and Yasukazu ASANO

DKK Corporation
Musashino-shi, Tokyo 180, Japan

Taste of food has been usually evaluated by an organoleptic test in food manufacturing process at present. However, it takes time and cost for this evaluation test. Therefore, it is expected to develop a sensing system for evaluation of test of foods. We have developed a FIA system combined with a chemiluminescence detector and an enzyme-column. For detecting low light of chemiluminescence efficiently, the flow cell was specially designed. And photodiode (not a photomultiplier) was used as a detector for the purpose of cutting down the apparatus cost. The hydrogen peroxide released from the conversion of glucose substance was monitored by chemiluminescence detector. Selectivity of this FIA system was satisfactory. and reproducibility was good.


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40
ƒtƒ[Œ^”|—{ƒVƒXƒeƒ€‚ð—p‚¢‚½_ŒoüˆÛ¬’·Šˆ«•¨Ž¿‚Ì’è—Ê“I•]‰¿

 ”–ì@NA–{ŠÔ’m•vAª–{‘×sA¼‰ª‰p–¾

“Œ”_H‘åH

EVALUATION OF NEURITE GROWTH ACTIVATING FACTOR USING FLOW TYPE COLTURE SYSTEM

Yasushi KAZUNO, Tomoo HOMMA, Yasuyuki NEMOTO and Hideaki MATSUOKA

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

The flow type culture system using cultured nerve cell, PC12h-R, was developed for the evaluation of neurite growth activating factors. This system enabled a sensitive and rapid assay. Owing to the flow system, the unexpected influence of metabolites from PC12h-R on neurite growth was minimized. Moreover, the same sample cells could be used for repeated assay for different agents. The actions of NGF or db-cAMP, for instance, were detected every one hour repeatedly. Projection and disappearance of neurite were synchlonyzed with the repeated supply and removal of db-cAMP. On the other hand, the neurite responses disappeared after 5 times supplies of NGF.


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41
…»U“®Ž®HSAƒZƒ“ƒi‚̉ž“š“Á«‚̉ü‘P

 ²”Œ‹MLAŽðˆä@„A‰F“c‘׎O*AŽO‰Y‘¥—YAŽR“Y@úf

‹ã‘呇—HAL“‡Œ§—§‘å

IMPROVEMENTS OF SENSING PROPERTIES OF PIEZOELECTRIC IMPROVEMENTS FOR HSA

Takahiro SAIKI, Go SAKAI, Taizo UDA*, Norio MIURA and Noboru YAMAZOE

Department of Materials Science, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816, Japan

*Hiroshima Prefectural University, School of Bioresources
Shoubara, Hiroshima 727, Japan

Improvements of sensing properties of a piezoelectric immunosensor for human serum albumin (HSA) were examined. The frequency change (¢F : sensitivity)was observed when the HSA solution was allowed to flow onto the quartz crystal sensor immobilized with anti-HSA monoclonal antibody. The ¢F was found to be further increased up to about 3 times after the subsequent flow of the polyclonal antibody solution, owing to the formation of a complex of HSA sandwiched with the two types of antibody. The finally obtained ¢F varied almost linearly with the HSA concentration in the range of 0-20 ppm, with the sensitivity of ca. 20 ppm/Hz. Moreover, it was found that the resonant frequency returned back reversibly to the initial level on the treatment with acidic buffer solution (pH 3.0), and then such measurements of HSA could be repeated up to 30 times without significant changes in sensitivity. These results assure enough sensitivity as well as good reusability of the sensor in the liquid flow-type HSA assay system.


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42
NASICON‚ð“à•”“d‰ðŽ¿‚Æ‚µ‚Ä—p‚¢‚½‘SŒÅ‘ÌŒ^ƒoƒCƒIƒZƒ“ƒT

 F. LisdatAŽR“cWLAŽO‰Y‘¥—YAŽR“Y¸

‹ã‘呇—H

A SOLID-STATE BIOSENSOR USING NASICON AS INTERNAL ELECTROLYTE

Fred LISDAT, Akihiro YAMADA, Norio MIURA and Noboru YAMAZOE

Department of Materials Science and Technology, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816, Japan

Based on a solid electrolyte cell a new potentiometric glucose sensor was developed. The sensor uses a sodium ion conductor (NASICON) as an internal electrolyte and can be represented by the following electrochemical scheme: air, Pt / NASICON(solid electrolyte) / Pt, enzyme layer (GOD). Response of the sensor to glucose follows Nernst's equation in the concentration range from 5x 10-5 to 5x 10-3 M with a slope of -53 mV/decade. The sensing mechanism is discussed on the basis of the H2O2 response of the sensor as well as the metal layer influence on the sensing behavior.


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43
ƒ|ƒŠƒAƒjƒŠƒ“”í•¢ƒ}ƒCƒNƒƒAƒŒƒC“d‹É‚ð—p‚¢‚½ƒOƒ‹ƒR[ƒXƒZƒ“ƒT‚Ì컂ƕ]‰¿

 ŽO˜aK°A¼àV¼•FA––‰i’qˆêA“à“c@—E

“Œ–k‘åH

FABRICATION AND CHARACTERIZATION OF CONDUCTMETRlC GLUCOSE SENSOR BASED ON MICROARRAY ELECTRODE COATED WITH POLYANILIME

Yukiharu MIWA, Matsuhiko NISHIZAWA and Tomokazu MATSUE and Isamu UCHIDA

Department of Molecular Chemistry and Engineering, Faculty of Engineering, Tohoku University
Aramaki-Aoba, Aoba-Ku, Sendai 980, Japan

Conductmetric glucose sensor was fabricated by coating a glucose oxidase (Gox)-gluconolactonase (Gla) polyaniline-electrodeposited microarray electrode. The enzyme-catalyzed hydrolysis of glucose induced a decrease in pH in the film and therefore the increase in the conductivity of the film. The sensor showed fast response to glucose in solution up to 1 mM.


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BIOSENSORS USING MODIFIED ENZYMES

Fumio MIZUTANI

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

We report here the usefulness of modified enzymes, such as polyethylene glycol-attached enzymes and lipid/enzyme complexes, for the construction of amperometric biosensors with high performance characteristics. The polymer-attached glucose oxidase (GOD), for example, shows higher activity than native enzyme in a hydrophobic carbon paste(CP) matrix, which results in an enhanced current response on the CP-based glucose electrode. A glucose-sensing electrode using a layer of lipid-modified GOD/Nafion layer shows rapid response and high stability. The immobilization of molecularly engineered dihydrofolate reductase on gold electrode is also described.


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44
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SELF-ASSEMBLY OF FERROCENE-MODIFIED GLUCOSE OXIDASE ON A GOLD-BLACK ELECTRODE

Munenori IMAMURA, Tetsuya HARUYAMA, Yoshihito IKARIYAMA and Masuo AIZAWA

Department of Bioengineering, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology
Nnagatsuta, Midoriku, Yokohama 227, Japan

Ferrocene-modified glucose oxidase was covalently bound to self-assembled aminoethane thiol on the gold-black electrode surface. Reversible electron transfer was demonstrated between the enzyme-bound ferrocene and the electrode. Enzymatic oxidation of glucose was efficiently coupled with the electrochemical oxidation of modified enzyme through the mediators.


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45
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DEVELOPMENT OF DISPOSABLE LACTATE SENSOR (REPORT 2)

Shiro NANKAI, Satoko FUJISAWA and Toshihiko YOSHIOKA

Matsushita Electric Industrial Co., Ltd.
3-1-1 Yagumo-nakamachi, Moriguchi-shi, Osaka 570, Japan

A disposable lactate sensor using potassium ferricyanide as an electron mediator was investigated. A L-lactate concentration could be measured up to ca.300 mg/dl in 60 seconds and to 50 mg/dl in 10 seconds. A L-lactate in diluted lactate beverage could be determined with the lactate sensor, containing phosphate buffer salt in its reaction layer. This sensor exhibited good storage characteristics for 2 months at 50°C under dry condition. The applicability of the lactate sensor to the determination of L-lactate in food and blood was evaluated .


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46
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RESPONSE CHARACTERISTICS OF GLUCOSE MEASUREMENT WITH ENZYME EMBODIED ELECTRODE (EEE) SENSOR IN WHOLE BLOOD

Masashi YAOITA, Sinichi OKADA*, Youko KANEKO**, Syunichi UCHIYAMA*, Yasuhiko YOSHIDA**, Yoshihito IKARIYAMA*** and Shigeru YAMAUCHl

Research Institute of National Rehabilitation Center for the Disabled
Tokorozawa, Saitama 359, Japan

*Dept. of Environmental Engineering, Saitama Institute of Technology
Okabe, Saitama 369-02, Japan

**Dept. of Applied Chemistry, Faculty of Engineering, Toyo University
Kawagoe, Saitama 350, Japan

***Dept. of Bioengineering, Tokyo Institute of Technology
Yokohama, Kanagawa 227, Japan

We applied an enzyme embodied electrode (EEE) to glucose measurement in whole blood with the potentiostatic pulse technique that is a transient technique. Response currents at 40 ms with the EEE sensor for glucose were 2.3 and 4.0 ƒÊA in blood containing 4.6 and 7.6 mM glucose , respectively. A calibration curve in blood accorded with that in phosphate buffered solution. From these results, we conclude that the pulse technique with the EEE sensor can be clinically used for whole blood without dilution.


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47
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OCTAETHOXYPHTHLOCYANINE-MEDIATED GLUCOSE-SENSING ELECTRODE

Fumio MIZUTANI, Soich YABUKI and Seiichiro IIJIMA

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

An amperometric sensor for glucose was prepared by incorporating a polyethylene glycol-modified glucose oxidase and cobalt octaethoxyphthalocyanine [Co(OEt)8], a new mediator, into a carbon paste matrix. The polymer-modified enzyme showed a higher activity than native enzyme in the matrix. CoPc(OEt)8 oxidized the enzyme at more negative potentials than non-substituted cobalt phtalocyanine (CoPc). Further, the CoPc(OEt)8-mediated enzyme electrode was highly stable: the electrode response to glucose did not decrease for 700 assays, whereas the glucose response from a CoPc-mediated enzyme electrode gradually reduced to be a half of the initial value within 300 assays. CoPc(OEt)8 , a paraffin oil-soluble derivative of CoPc, in the balk of carbon paste would diffuse to wards the electrode surface so as to renew continuously the surface, which resulted in the high stability of the new mediator-based enzyme electrode.


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48
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ENZYME-EXCHANGEABLE ENZYME ELECTRODES EMPLOYING A PHASE-TRANSITION REDOX GEL

Tetsu TATSUMA, Ken-ichi SAITO and Noboru OYAMA

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

A thermoshrinking redox gel which is swollen below 22 °C and shrunken above 35 °C was prepared on an electrode. A water-soluble enzyme, glucose oxidase (GOx) and lactate oxidase (LOx), can be introduced into the gel below 22 °C and held in the gel above 35 °C. The GOx-loaded and LOx-loaded gel-coated electrodes respond amperometrically to glucose and lactate, respectively, at 35 °C , even under nitrogen. Thus, the thermoshrinking redox gel functions both as an enzyme support and as an electron mediator between the enzyme and electrode. The trapped enzyme can be unloaded by swelling the gel, and the gel electrode can be reloaded with a fresh enzyme. Further, the trapped LOx can be exchanged for GOx to change the lactate sensor to a glucose sensor, and vice versa.


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49
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APPLICATION OF CHOLINE-ACETYLCHOLINE SENSOR TO BODY FLUIDS

Masayuki KIKUOKA, Yoshio KOKUSENYA, Noriyuki NISHIMURA and Tadashi SATO

Analytical Chemistry Research Laboratory, Tanabe Seiyaku Co., Ltd.
16-89 Kashima 3-chome,Yodogawa-ku,Osaka 532, Japan

An enzyme electrode was made by immobilizing choline oxidase and acetylcholine esterase on platinum wires for investigation on the determination method of choline and acetylcholine in vivo. The enzyme electrode was able to measure 0.1 ƒÊM to 5 ƒÊM of choline and acetylcholine. Further Nafion coating was tried to apply on the electrode to eliminate such inhibitors in vivo as ascorbic acid. Total choline content in plasma and cerebrospinal fluid of rat was determined with the enzyme electrode, and the result was compared with the data obtained by HPLC.


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50
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BIOSENSING OF UREA USING AN ACID UREASE COLUMN

lkuo SATOH, Yoshiko FUJITA and Masahiro NEMOTO

Department of Chemical Technology, Faculty of Engineering, Kanagawa Institute of Technology
1030 Shimo-Ogino, Atsugi-shj, Kanagawa-ken 243-02, Japan

Biosensing of urea in acidic media was investigated with use of acid urease immobilized on cellulose beads. The sensing system was equipped with the enzyme-column and a flow-injection photometric device. Ammonical molecules enzymatically formed in the hydrolysis of urea were photometrically detected as change in absorbance at 596 nm. The calibration graph was linear up to 1.25 mM for 0.25-mL injections of urea standards . The relative standard deviation for 0.5 mM urea was 2 %(n-10). The assay took 8 min.


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