Vol. 6, Supplement B (1990)

Digest of the 11th Chemical Sensor Symposium
September 29-30, 1990
Chiba University


Abstracts


1
ƒz[ƒ‹Œø‰Ê‘ª’è‚ð—p‚¢‚½Ž_‰»Žà”¼“±‘̃KƒXƒZƒ“ƒT‚Ì“®ì‹@\‚ÌŒ¤‹†

ˆê–{¼³“¹E‘吼‹v’jE²X–Ø”ŽˆêE¼–{@‹B

‘åãƒKƒXŠî”ÕŒ¤

STUDY FOR SENSING MECHANISM OF SnO2 SEMICONDUCTOR FLAMMABLE GAS SENSOR USING HALL EFFECT MEASUREMENT

Masamichi IPPOMMATSU, Hisao OHNIAHI, Hirokazu SASAKI, Takeshi MATSUMOTO

Foundamental Research Lab., Osaka Gas Co., LTD,
Konohana-ku, Osaka 554, Japan

Measurement were made on the Hall effect of SnO2 thin film flammable gas sensors prepared by using the reactive sputtering method. The results revealed that when the electrical conductivity of the sensors changed with a change in the flammable gas density in air, the apparent carrier density changed significantly while apparent mobility hardly changed at all. However, detailed analysis revealed that this experimental result could not be explained by using the double Schottky model or the neck model that had been proposed. In order to provide satisfactory explanation of the experimental results, the authors proposed that for SnO2 thin films there exists no distinction between bulk and surface of the grain while the carrier densities of bulk and surface of the grain simultaneously changed with a change in oxygen adsorption of the SnO2 surface in the presence of flammable gas. This model was in good agreement with the results of TEM observation using the ultrathin film technique.


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2
SnO2ŒnƒZƒ“ƒT‚ÌDebye’·‚³‚Æ—±ŽqŒa‚É‚æ‚éƒKƒXŠ´“x‚̐§Œä

™@’´’jE‹Ê’u@ƒEŽO‰Y‘¥—YEŽR“Y@úf

‹ã‘呍‡—H

CONTROL OF GAS SENSITIVITY OF SnO2-BASED GAS SENSORS BY DEBYE LENGTH AND CRYSTALLITE SIZE

Chaonan XU, Jun TAMAKI, Norio MIURA and Noboru YAMAZOE

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

The gas sensitivity of SnO2-based gas sensors was investigated in relation to Debye length (L) and crystallite size (D) of SnO2. By partial substitution of Al3+ or Sb5+ for Sn4+, the Debye length of SnO2 varied from 0.1 nm to 90 nm as a result of valence control. The gas sensitivity of undoped SnO2 sensor to H2 increased dramatically when D decreased down to around 6 nm (=2L). The Sb-doped SnO2 sensors with small L (0.1 nm) always showed low sensitivity, while Al-doped SnO2 sensors having large L (90 nm) gave high sensitivity even if D was as large as 20 nm. This results support that the gas sensitivity increased as D/2L approaches to 1 or less either by decreasing D (pure SnO2) or by increasing L (doped SnO2).

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3
Ž_‰»ƒXƒYƒEƒBƒXƒJ[‚̐…‘fƒKƒXŠ´“x‚̍‚Š´“x‰»‹@\

´…N”ŽE’†”öK“ñEˆä”ó‹M•vE]“ª@½

POSSIBLE FACTORS CONTRIBUTING TO THE AUGMENTATION IN HYDROGEN SENSITIVITY OF TIN OXIDE WHISKERS

Yasuhiro SHIMIZU, Koji NAKAO, Takao IBI and Makoto EGASHIRA

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

Sensitivity of the as-prepared SnO2 whiskers to 1% H2 was 3-5 at most. After thermal treatments in an atmospheric environment under turning on electricity to the whiskers, however, the sensitivity increased significantly to several ten thousand. Possible factors contributing to the augmentation in the hydrogen sensitivity have been investigated. It was revealed that water vapor played an important role to enhance the sensitivity, whereas magnitude of the applied voltage during the treatments presented no effect on the sensitivity.

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4
”¼“±‘ÌŽ®ƒtƒƒ“ƒKƒXƒZƒ“ƒT‚ÌŠJ”­

–쑺@“OE¼‰Y‹g“WE‚”©@ŒhE¼‰Yr“ñ

ƒtƒBƒKƒ‹ZŒ¤

DEVELOPMENT OF SEMICONDUCTOR FREON GAS SENSORS

Tohru NOMURA, Yoshinobu MATSUURA, Kei TAKAHATA and Shunji MATSUURA

Figaro Engineering Inc.
Minoo, Osaka 562, Japan

Metal oxide semiconductor gas sensors generally show low gas sensitivity to freons such as R-11 (CCl3F), R-12 (CCl2F2) and R-113 (CCl2FCClF2). In order to improve the gas sensitivity to freons in SnO2 gas sensors, 39 kinds of elements were added and their sensitivity was examined. The addition of sulfur resulted in high sensitivity to the freons. The sensor element doped with sulfur was also characterized by means of FT-IR.

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5
ƒtƒƒ“ƒKƒXƒZƒ“ƒT‚̃AƒvƒŠƒP[ƒVƒ‡ƒ“

£ŒËŒû‘׍OE–쑺@“OE“V–{‘¾˜YE“c’†Ž”VE¼‰Yr“ñ

ƒtƒBƒKƒ‹ZŒ¤

APPLICATION OF FREON GAS SENSOR

Yasuhiro SETOGUCHI, Tohru NOMURA, Taro AMAMOTO, Katsuyuki TANAKA and Shunji MATSUURA

Figaro Engineering Inc.
Minoo, Osaka 562, Japan

As freons have the following properties such as volatility, low combustibility, chemical stability and low toxicity, they are used in various industrial fields. However, freons have restricted in usage, since they destroy the ozone layer of the earth. Due to this situation the demand for freon checkers to detect freon gas leakage and to control the apparatus for freon recovery system has increased recently.
In this report, we describes the application example of freon sensor, the important points of usage and the gas sensitivity of SnO2 gas sensor to some CFC chemical substitutes.

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6
CuO-SnO2 Œn H2S ƒZƒ“ƒT

‘Oì’m‹PE‹Ê’u@ƒEŽO‰Y‘¥—YEŽR“Y@úf

‹ã‘呍‡—H

H2S DETECTION USING CuO-SnO2 SENSOR

Tomoki MAEKAWA, Jun TAMAKI, Norio MIURA and Noboru YAMAZOE

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

A CuO-loaded SnO2 element was found to have unique sensing properties for H2S. At a CuO loading of 5 wt%, the sensitivity to 50 ppm H2S in air was as high as 35,000 at 200Ž or below, while it decreased drastically at higher temperature. Moreover, the recovery of the electric resistance on turning off H2S was extraordinary quick, resulting in a switching-like phenomenon. The element was exclusively selective to H2S, with small sensitivity of 1`2 to H2, CO, CH4, i-C4H10, C2H5OH. It is considered that the loaded CuO, which is combined with the surface of the SnO2 particles to form a p-n junction in air, changes into conductive CuS in H2S containing atmospheres. This change of state between CuO and CuS seems to be an origin of the unique sensing properties for H2S.

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7
Ž_‰»•¨”¼“±‘̃KƒXƒZƒ“ƒT‚ð—p‚¢‚½ƒCƒJ‚Ì‘N“x‘ª’è

‚”ö—Y“ñE´…N”ŽE]“ª@½E‘å‹´‰pŽ¡E¬‘òº•v*

’·è‘åHC“ú–{…ŽY’†Œ¤*

DETECTION OF FRESHNESS OF SQUID BY METAL OXIDE SEMICONDUCTOR GAS SENOSRS

Yuji TAKAO, Yasuhiro SHIMIZU, Makoto EGASHIRA, Eiji OHASHI* and Akio OZAWA*

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

* Central Research Laboratory, Nippon Suisan Kaisha, Ltd.
559-6 Kitano, Hachioji, Tokyo 192, Japan

Attempts were made to detect freshness of squid by In2O3 and In2O3+MgO sensor. Electrical resistance of these sensor elements responded well to the deterioration of the squid muscle after its death. The addition of small amount of KOH aqueous solution to the squid muscle resulted in an increase in resistance change. In addition, it was revealed that the resistance was well proportional to the concentration of trimethylamine (TMA) in the squid muscle.

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8
”¼“±‘̐«‚•ªŽq–Œ‚ð—p‚¢‚½ƒAƒ“ƒ‚ƒjƒAƒKƒXƒZƒ“ƒT

Žðˆä‹`˜YE¼Œû³ME’艪–F•F

ˆ¤•Q‘åH

AMMONIA GAS SENSOR BASED ON SEMICONDUCTIVE POLYMER FILM

Yoshiro SAKAI, Masanobu MATSUGUCHI and Yoshihiko SADAOKA

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

An ammonia gas sensor was prepared by using the soluble polyaniline in organic solvents which was synthesized by chemical oxidation at low temperature followed by dedoping with aqueous ammonium solution. The ployaniline was dissolved in N-methyl-2-pyrrolidone and was dip-coated on an alumina substrate having a pair of interdigitated gold electrodes. The conductivity of the sensor responded reversibly to the alternate introduction of NH3 and air. The pre-heating of the sensor was effective to increase the conductivity. It also reduced the drift in the long period of use and made the response quicker. The pre-heated samples were observed through an scanning electron microscope. The heating made the surface of the film rough and made the film harder than the original one. The response of this sensor to NH3 can be explained in terms of the compensation effect on the small amount of residual acceptor dopant.

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9
ƒtƒ^ƒƒVƒAƒjƒ“”––Œ‚ð—p‚¢‚½NO2ƒKƒXƒZƒ“ƒT

¼Œû³ME’艪–F•FEŽðˆä‹`˜Y

ˆ¤•Q‘åH

NO2 SENSOR WITH METAL-SUBSTITUTED PHTHALOCYANINE THIN FILM

Masanobu MATSUGUCHI, Yoshihiko SADAOKA and Yoshiro SAKAI

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

Effects of heat treatment on the crystal structure and morphology of phthalocyanine with various divalent central metals were examined. For the phthalocyanines with Zn, Cu and Co, the crystal growth was observed by heat treatment while lead phthalocyanine was deformed by reacting with oxidizing molecules and remained small crystals. The reproducibility and a fast recovery time were observed only for lead phthalocyanine. The presence of larger crystal induce the lack of the reproducibility and a fast recovery time.

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10
LaF3ƒQ[ƒg MOS Œ^Ž_‘fƒZƒ“ƒT‚Ì“Á«‰ü‘P

Œ´@³ŽjEŸ•”º–¾E‹Ú‘ò˜aò*EÎ‹´‹I—Y*E–؉ººˆê*EˆÀ’BL—Y*EŽO‰Y‘¥—Y**EŽR“Y@úf**

é‹Ê‘åHEƒI[ƒN*E‹ã‘呍‡—H**

IMPROVEMENT OF SENSING CHARACTERISTICS OF A MOS TYPE OXYGEN SENSOR WITH LaF3 GATE ELECTRODE

Masashi HARA, Teruaki KATSUBE, Izumi SERIZAWA*, Norio ISHIBASHI*, Shoichi KINOSHITA*, Nobuo ADACHI*, Norio MIURA** and Noboru YAMAZOE**

Saitama University
Shimo-okubo, Urawa, Saitama 338, Japan

* ORK Co., Ltd.
Chofu-ga-oka, Chofu, Tokyo 182, Japan

** Graduate School of Engineering Science, Kyushu University
Kasuga-shi, Fukuoka 816, Japan


This report deals with improvements on response speed and humidity interference of a MOS type oxygen sensor using sputtered LaF3 film which is operative at room temperature. It was shown that a water vapor treatment was effective to increase the response speed. BY the treatment with 15 Torr water vapor at 90Ž for 1 h, the response speed was improved to 2.5 min from 15.0 min of the as-sputtered sample. TEFLON film coating was effective to reduce the interference of humidity on the sensor response. Preliminary experiment showed that the sensor became almost insensitive to humidity when coated with sufficiently thick TEFLON film (>2000 A).

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“Á•Êu‰‰‚P
ÔŠO•ªŒõ–@‚ð—p‚¢‚½‚‰·ƒKƒX‚Ì‚»‚̏ꕪÍ

‘O“c³Žj

“Œ‘吶Œ¤

IN SITU FIBER OPTIC SENSING TECHNIQUE USING INFRARED SPECTROSCOPY TO DETERMINE CHEMICAL COMPOSITION AND TEMPERATURE OF HIGH TEMPERATURE GAS

Masafumi MAEDA

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

A new technology for sensing gases utilizing infrared spectroscopy has been developed for determining chemical composition and temperature. An infrared optical sensor used was with a water cooled probe equipped with KRS-5 fiber and a zinc selenide lens. With this sensor, infrared light could be introduced from a high temperature furnace to a FTIR spectrometer. Carbon monoxide, CO2 and H2O gas were successfully analyzed. The shape of the vibrational-rotational spectrum was a function of temperature as expected by Boltzmann's distribution law which is a function of temperature. Carbon monoxide was chosen as a probe molecule for temperature measurement. Temperature of CO gas from 1000 to 1550Ž was measured.


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11
ƒvƒƒgƒ““±“d«ƒZƒ‰ƒ~ƒbƒNƒX‚ð—p‚¢‚½…‘f‹y‚ѐ…ö‹CƒZƒ“ƒT
\SrCeO3Œn‚ÆCaZrO3ŒnƒZƒ“ƒT‚̐«”\‚Ì”äŠr\

¬o–M”ŽEŽR–{ŒN“ñE–@•Û*EŠâŒ´Oˆç*

TYKE–¼‘åH*

HYDROGEN AND STEAM SENSOR USING PROTON CONDUCTING CERAMICS
-COMPARISON OF PERFORMANCE OF CaZrO3-TYPE SENSOR WITH THAT OF SrCeO3-TYPE SENSOR-

Kunihiro KOIDE, Kunji YAMAMOTO, Tamotsu YAJIMA* and Hiroyasu IWAHARA*

Research and Development Center, TYK Corporation
3-1 Ohbata-cho Tajimi 507, Japan
*Synthetic Crystal Research Laboratory, Faculty of Engineering, Nagoya University
Furo-cho Chikusa-ku, Nagoya 464-01, Japan

Using SrCe0.95Vb0.05O3-ƒ¿ and CaZr0.9In0.1O3-ƒ¿ as a solid electrolyte, Nernstian-type hydrogen/steam sensors were constructed. The performances of these sensors were compared under various conditions. Both sensors showed stable emfs in correspondence with the partial pressure of hydrogen and water vapor at 700Ž. In contrast to SrCeO3-type sensor, CaZrO3-type sensor didn't deteriorate in the presence of CO2. The deterioration of SrCeO3-type sensor was ascribed to the attack of CO2 to SrCeO3 to form SrCO3 and CeO2.


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12
ƒvƒƒgƒ““±“d«ŒÅ‘Ì“d‰ðŽ¿‚ð—p‚¢‚½ŠE–ʐ…•ªŒŸoƒZƒ“ƒT

ˆî‰i˜a•FE‘¾“c@ÖE•c‘ºNŽŸEŽR“àŽl˜Y*

ŽO•H“d‹@

A SENSOR USING PROTON CONDUCTOR FOR DETECTION OF THE ABSORBEDWATER ON CONTACT SURFACE

Kazuhiko INANAGA, Hitoshi OTA, Koji NAMURA and Shiro YAMAUCHI*

Mitsubishi Electric Corporation, Central Research Laboratory
Amagasaki-shi, Hyogo 661, Japan
*Mitsubishi Electric Corporation, Itami Works
Amagasaki-shi, Hyogo 661, Japan

A method for detecting the water film absorbed on contact surface is investigated using the sensor which is consisted of a proton conductor (Nafion membrane). Cyclic voltammetry and complex impedance analysis are performed for a variety of relative humidities. Current-voltage curves obtained by cyclic voltammetry show that the current increases at the electrolytic potential of the water and the maximum value of the current becomes large in accordance with an increase in relative humidity. From Cole-Cole plot analysis, the resistance of Nafion membrane is separated from that of Nafion-electrode interfacial properties. These results mean that the water film absorbed on contact surface is estimated quantitatively by the measurement of changes in the resistance of Nafion membrane.


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13
ƒŠƒ`ƒEƒ€ƒCƒIƒ““`“±‘Ì‚ð—p‚¢‚½ŒÅ‘Ì“d‰ðŽ¿ƒZƒ“ƒT‚Ì‘I‘ð“ICO2ŒŸo”\

‰Í—¢@Œ’E¡’†MlE‘«—§‹á–ç

ã‘åH

SELECTIVE CO2 SENSING WITH SOLID ELECTROLYTE BASED ON LITHIUM IONIC CONDUCTOR

Takeshi KAWASATO, Nobuhito IMANAKA and Gin-ya ADACHI

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

Selective CO2 sensing in several gases coexisting atmosphere was investigated with a CO2 sensor based on a lithium conducting solid electrolyte, LiTi2(PO4)3+0.2Li3PO4. NO2 coexistence in the atmosphere influenced little to the CO2 detection. The sensor was able to detect CO2 selectively in the atmosphere where the SO2 concentration was lower than approximately 20 ppm. In the case of CH4 coexisting atmosphere, the total amount of CO2 which was primarily introduced and CO2 formed from the CH4 oxidation, was obtained with the sensor.


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14
Na+“±“d‘Ì‚ð—p‚¢‚½ CO2 ƒZƒ“ƒT

›L@ŸE´…—zˆêE’艪–F•F*EŽO‰Y‘¥—YEŽR“Y@úf

‹ã‘呍‡—HEˆ¤•Q‘åH*

CO2 SENSOR USING SODIUM ION CONDUCTOR

Sheng YAO, Youichi SHIMIZU, Yoshihiko SADAOKA*, Norio MIURA and Noboru YAMAZOE

Department of Materials Science and Technology, Graduate School of Engineering Sciences, Kyushu University
Kasuga-shi, Fukuoka 816, Japan
*Department of Industrial Chemistry, Faculty of Engineering, Ehime University
Matsuyama 790, Japan

A simple potentiometric CO2 sensor based upon a sodium ion-conduction solid electrolyte (NASICON) was found to be greatly improved in response time and water vapor-resistance by using a binary carbonate electrode of BaCO3-Na2CO3. For a wide range of CO2 concentration from 4 to 400,000 ppm, the electromotive force examined at 823 K followed a Nernst's equation excellently, with a 90% response time of as short as 8 s. Water vapor hardly affected the sensor characteristics, in remarkable contrast to the case of a pure Na2CO3 electrode.


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15
”RÄ‹@Ší”rƒKƒX’†‚É‚¨‚¯‚é”––ŒŒ^ŒÀŠE“d—¬Ž®Ž_‘fƒZƒ“ƒT‚Ì“Á«

“ñ“c•äÏEˆÀŒ`˜arE—é–Ø—²”V*E’|“à³Ž¡*E‚‹´‰pº*E²Ž¡Œ[Žs*E‹ß“¡t‹`*

–îèŒvŠíE–L“c’†Œ¤*

CHARACTERISTICS OF THIN-FILM LIMITING CURRENT-TYPE OXYGEN SENSOR IN EXHAUST GAS OF COMBUSTION APPLIANCES

Hozumi FUTATA, Kazutoshi ANGATA, Takayuki SUZUKI*, Masaharu TAKEUCHI*, Hideaki TAKAHASHI*, Keiichi SAJI* and Haruyoshi KONDO*

Yazaki Meter Co., Ltd. Gas Appliance Laboratory
Futamata-cho Tenryu-shi, Shizuoka 431-33, Japan
*Toyota Central Research and Development Laboratories Inc.
Nagakute-cho Aichi-gun, Aichi 480-11, Japan

It seems these days that environmental problems, such as global temperature rise and acid rain disasters have been increasingly crucial. The problems are obviously resulted from emitted materials by fossil-fuel combustion for the most part. Specimens of a thin-film limiting current-type oxygen sensor, being incorporated into the small-type burners of gas appliances such as instant water boilers, are tested as a gas-combustion control device which controls emission of problematic gases. Particularly, the specimens are investigated on their characteristic performance and controlling ability which prevents incomplete combustion when they are exposed to exhaust emitted from several instant water boilers. The output of this sensor unit for normalized air-to-fuel ratio ă in exhaust gas of the hot-water supplier is, for example, about 39 mV in the case of ă= 1.2, and about 100 mV in the case of ă= 1.8.
Each specimen shows capable of pleventing incomplete combustion that likely occurs as the result of blocking or choking the air inlet.


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16
‹z’…ƒ‹ƒ~ƒlƒbƒZƒ“ƒX‰»ŠwƒZƒ“ƒT

“¡Œ´é’ʁE’†ì‰v¶E¼‰Y•Û²*E•yŽR@‹B*EŽR–{@ŒM*E‰F“s‹{W**E˜a“c‹ä“T***EŽR–{M•F***EŽR‰º­•F***

‰ªŽR—‘嗝E‰ªŽR—‘åH*E‰ªŽR—‘勳**E‰ªŽR‘嗝

ADSORPTION LUMINESCENCE CHEMICAL SENSOR

Nobumichi FUJIWARA, Masuo NAKAGAWA, Yasuaki MATSUURA*, Tsuyoshi TOMIYAMA*, Isao YAMAMOTO*, Koh UTSUNOMIYA**, Tomonori WADA***, Nobuhiko YAMASHITA*** and Yoshihiko YAMASHITA***

Faculty of Science, Okayama University of Science
1-1 Ridai-cho, Okayama 700, Japan
*Faculty of Engineering, Okayama University of Science
1-1 Ridai-cho, Okayama 700, Japan
**Faculty of Liberal Arts and Science, Okayama University of Science
1-1 Ridai-cho, Okayama 700, Japan
***Faculty of Science, Okayama University
3-1-1 Tsushimanaka, Okayama 700, Japan

A new method for the measurement of combustible gases in air is proposed. When vapor of combustible organic solvents (e.g. ethanol, acetone and benzene) is injected into surrounding air atmosphere, luminescence is emitted from alumina powder heated to 250-480Ž. The luminescence intensity is proportional to the concentration of the solvent vapor in air, so that this effect can be applied to the measurement of combustible gas concentration in air. The lower detection limit is of the order of 1 ppm by the use of a photomultiplier as an optical detector. The typical response time (time taken to reach 90% of the final signal) is about 1 min. and reproducible for repetitive atmosphere change. Furthermore, the luminescence has a band spectrum ranging from 350 to 650 nm, and its profile is dependent on the chemical species of the combustible vapor. This luminescence may result from recombination of electron hole pair, which originates from adsorption surface states, through luminescence center produced by the chemisorption of solvent vapor


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17
ƒ}ƒCƒNƒƒ}ƒVƒ“‹Zp‚É‚æ‚éŽ_‘f“d‹É‚̍쐻

—é–Ø”ŽÍE¬“ˆ®”üE›ŠÔ–¾•v

•xŽm’ÊŒ¤

FABRICATION OF AN OXYGEN ELECTRODE BY MICROMACHINING TECHNIQUES

Hiroaki SUZUKI, Naomi KOJIMA and Akio SUGAMA

Organic Materials Laboratory, FUJITSU LABORATORIES LTD.,
Atsugi, Kanagawa 243-01, Japan

A miniature Clark-type oxygen electrode was fabricated using micromachining techniques. A three-electrode configuration was used. The electrodes were formed on a 7740 glass substrate and a container made by anisotropically etching silicon was anodically bonded to the glass substrate. An FEP gas-permeable membrane was thermally adhered to a silicon area where a hole was made over the working electrode. By incorporating new techniques, we developed a new process that allows simultaneous electrode formation until we cut off the chips. A good linear calibration curve was obtained at 25Ž.


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18
ƒeƒtƒƒ“/(AgClEƒeƒtƒƒ“)Ï‘w\‘¢‚ð—p‚¢‚½Šî€“d‹É

‘å—䐭Ž÷EŒ´@³ŽjEŸ•”º–¾EŽRŒûGˆê˜Y*E‰º‘º@‹B*

é‹Ê‘åHEƒeƒ‹ƒ‚*

SOLID STATE REFERENCE ELECTRODE COMPOSED OF TEFLON/(AgClETEFLON) MULTI LAYER STRUCTURE

Masaki OMINE, Masashi HARA, Teruaki KATSUBE, Shuichiro YAMAGUCHI* and Takeshi SHIMOMURA*

Faculty of Engineering, Saitama University
Shimo-okubo, Urawa 338, Japan
*R & D Center. Terumo Co., Ltd.
1500 Inokuchi Nakai-machi, Kanagawa 259-01, Japan

A novel structure of a solid state reference electrode was investigated with a cumulated layers consisting of TEFLON film and (AgClETEFLON) mixed film. The multi layers were fabricated by a neutral atomic beam sputtering with double beam guns. It was shown that the reference electrode had an almost constant output voltage over the pH range 4-9 and Cl- ion concentration range 0.01-1.0 mol/l. The stable response was maintained for longer than 8 hours in a buffered solution. These characteristics were influenced mainly by the compositions, thicknesses and cumulated numbers of the multi layers and the response improvement was discussed by considering the optimization of these parameters.


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19
ƒ|ƒŠƒAƒjƒŠƒ“–Œ‚̐…‘fƒCƒIƒ“‘I‘𐫂¨‚æ‚ѐ…Ž_ƒCƒIƒ“‘I‘𐫂̕]‰¿

’|’†@–LEtŽR—²”V

ƒIƒ€ƒƒ“’}”gŒ¤

EVALUATION OF SELECTIVITY COEFFICIENTS, KH+AK+, KH+ANa+, KOH-ACl-, AND KOH-ANO3-, WITH A POLYANILINE FILM

Yutaka TAKAENAKA and Takayuki HARUYAMA

Tsuyuba Laboratory, Omron Corporation
45 Wadai Tsukuba, Ibaraki 300-42, Japan

Selectivity coefficients, KH+AK+, KH+ANa+, KOH-ACl-, and KOH-ANO3-, with a Polyaniline (PAn) film were investigated. Measurement of potential vs SCE with a PAn film was made on a system of PAN/NESA/ITO/glass in standard buffer solutions of pH 4.01, 6.86, and 9.18 in addition to KCl, and NaNO3 at ca.22Ž. The deviation of the value of pH due to the change of the total ionic strength of the solution was corrected. Relationships between potential with a PAn film and the concentrations, 10-1`10-5 M, of KCl, and NaNO3 were examined. The results obtained by mixed solution method were as follows : selectivity coefficients in pH 4.01 : KH+AK+=10-1.51, KH+ANa+=10-1.90, KOH-ACl-=10-7.49, and KOH-ANO3-=10-7.88, selectivity coefficients in pH 6.86 : KH+AK+=10-4.94, KH+ANa+=10-5.28, KOH-ACl-=10-5.22, and KOH-ANO3-=10-5.56. No effect of K+, Na+, Cl-, and NO3- on potential with a PAn film was observed in pH 9.18.


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20
Ž_‘f‚ªƒ|ƒŠƒAƒjƒŠƒ“–Œ‚ð—p‚¢‚½ pHƒZƒ“ƒT‚É‚¨‚æ‚Ú‚·‰e‹¿

’|’†@–LEtŽR—²”V

ƒIƒ€ƒƒ“’}”gŒ¤

pH SENSOR USING A POLYANILINE FILM PRESERVED IN OXYGEN

Yutaka TAKENAKA and Takayuki HARUYAMA

Tsukuba Laboratory, Omron Corporation
45 Wadai Tsukuba, Ibaraki 300-42, Japan

Characteristics of pH sensor using a Polyaniline (PAn) film preserved in O2 was investigated. Measurement of absorbance vs air was made on a system of PAn/NESA/ITO/glass preserved in O2, O2 + silica gel, air, air + silica gel, air + oxygen absorber, air + oxygen absorber + silica gel for 7 days. Rates of change of absorbance with a PAn film preserved in O2, and O2 + silica gel were larger than in another atmospheres. Rates of change of absorbance with a PAn film preserved in air + oxygen absorber, air + oxygen absorber + silica gel were smaller than in another atmospheres. Therefore, the change of absorbance attributes to O2. Rates of change of absorbance with a PAn film preserved in O2 + silica gel were larger than in O2. Measurement of potential vs SCE was made on a system of PAn/NESA/ITO/glass, preserved in O2, O2 + silica gel, air, air + oxygen absorber, air + oxygen absorber + silica gel for 8 days, in standard buffer solutions such as pH 1.68, 4.01, 6.86, 9.18, 10.02 at room temperature. Potentials with a PAn film preserved in O2, and O2 + silica gel were in proportion to the value of pH of the solution over the range of pH 1.68`10.02 without measuring repeatedly.


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21
•s“®‘Ô‰»Œ»Û‚̉»ŠwƒZƒ“ƒT‚ւ̉ž—p
\‚”Z“x—̈æ‚É‚¨‚¯‚é—°Ž_ƒCƒIƒ“‚Ɛ…‘fƒCƒIƒ“”Z“x‚Ì“¯Žž‘ª’è\

ÎŒ´Œ°ŒõE’©‘qjŽ¡

‰¡•l‘‘å

APPLICATION OF PASSIVATION PHENOMENA TO CHEMICAL SENSORS
THE SIMULTANEOUS MONITORING OF THE HIGH CONCENTRATIONS OF HYDROGEN ION AND SULFATE ION

Akimitsu ISHIHARA and Shukuji ASAKURA

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

The authors proposed a new method measuring hydrogen ion and sulfate ion in concentrated acids by using passivation and depassivation phenomena. The basic idea underlying this method is that the transitions between active and passive states are sensitively affected by the chemical composition of a solution.
Both passivation and depassivation time are the functions of the concentrations of hydrogen ion and sulfate ion. The contour lines of passivation time can be plotted on a single plane. The intersecting point of these two lines gives the concentrations of hydrogen ion and sulfate ion in the test solution.


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22
SIS/ISFET‚É‚æ‚éA•¨Í”|—{‰t‚̐¬•ª‘ª’è

‰J‹{@Œ÷E”ª–؁@‹ÏEŽðˆä’‰Ži

“ŒŽÅ‘Œ¤

MEASUREMENT OF IONIC CONCENTRATION OF NUTRIENT SOLUTION FOR PLANTS USING SIS/ISFET

Isao AMEMIYA, Hitoshi YAGI and Tadashi SAKAI

Research & Development Center, Toshiba Co.,
1 Komukai Toshiba-cho Saiwai-ku, Kawasaki 210, Japan

Application of ISFETs to an ionic sensor for control system of nutrient solution in nutriculture, especially rockwool culture, has been investigated. Two types of SIS/ISFET; differntial-type and single-type, were used for experiments. Using the rockwool bed with an artificial nutrient solution, followed basic characteristics of sensors was examined: 1) pH response, 2) output dependence on the water content of bed, 3) long-term stability in bed; incase of using reference electrode, 4) output dependence on the water content of bed, 5) dependence on the distance between ISFET and reference electrode, 6) stability of liquid junction potential of reference electrode in bed. As a result of these experiments, the sufficient prospect was obtained.


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23
y‘f“d‹É‚É—p‚¢‚éƒvƒŒ[ƒiŒ^”äŠr“d‹É‚ÌŠJ”­

rˆä^lE‰““¡‰pŽ÷E’†“ˆ@‘E‘ê‘òkˆê

ƒIƒ€ƒƒ“ƒ‰ƒCƒtƒTƒCƒGƒ“ƒXŒ¤

DEVELOPMENT OF A PLANER-TYPE REFERENCE ELECTRODE FOR POTENTIOMETRIC ENZYME ELECTRODES

Masato ARAI, Hideaki ENDO, Satoshi NAKAJIMA and Koichi TAKIZAWA

OMRON INSTITUTE OF LIFE SCIENCE
17 Chudoji Minami-machi Shimogyo-ku, Kyoto 600, Japan

A planer-type reference electrode (Ag/AgCl) based on ceramic plate was developed and its characteristics were compared with glass reference electrode. Interfering ions such as pH (H+), Na+ and K+ had less effect. By using this reference electrode, pH electrode and urea electrode were fabricated, and those electrodes had similar response to glass reference electrode.


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24
ƒtƒ[Œ^“d‹C‰»ŠwƒoƒCƒIƒZƒ“ƒTƒVƒXƒeƒ€‚ɑ΂·‚é“d‹ÉŠˆ«–WŠQ•¨Ž¿‚Ì“d‹C‰»Šw“IƒIƒ“ƒ‰ƒCƒ“œ‹Ž

‘åì—S•ãE¬—Ñ—TKE‘å–ì—²Ži

ç—t‘åH

ELECTROCHEMICAL ON-LINE ELIMINATION OF ELECTROACTIVE INTERFERENTS FOR FLOW-TYPE BIOSENSOR SYSTEM

Yusuke OKAWA, Hiroyuki KOBAYASHI and Takashi OHNO

Department of Image Science and Engineering, Chiba University
Yayoi-cho, Chiba 260, Japan

A newly designed flow-through electrolytic cell, an electrochemical filter (ECF), successfully eliminated electroactive interferents to electrochemical biosensors (e.g. ascorbic acid) by complete electrolysis. The ECF wascombined with a glucose oxidase chemically modified SnO2 electrode in a flow injection analysis setup. Glucose content in soft drinks was determined without any pretreatment of the sample.


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25
“Æ—§Œ^ƒAƒŒƒC“d‹É‚ð—p‚¢‚½ƒ}ƒ‹ƒ`y‘fƒZƒ“ƒT‚ÌŽŽì‚Æ•]‰¿

Â–؁@ƒE––‰i’qˆêE“à“c@—E

“Œ–k‘åH

FABRICATION OF MULTI-ENZYME SENSOR USING INDIVIDUALLY ADDRESSABLE POTENTIOSTATED ARRAY ELECTRODE

Atsushi AOKI, Tomokazu MATSUE and Isamu UCHIDA

Department of Molecular Chemistry & Engineering, Faculty of Engineering, Tohoku University
Aramiki-Aoba Aoba-ku, Sendai 980, Japan

An amperometric multi-enzyme sensor was fabricated using an individually addressable potentiostated array electrode. Enzymes were entrapped in a polypyrrole membrane on an electrode surface of array electrode by electropolymerization of pyrrole. Two kinds of oxidoreductase, diaphorase and glucose oxidase was used in this study. The electrochemical oxidation of the substrate was catalyzed by the enzymes immobilized on the array electrode using an electron-transfar mediator (ferrocenylmethanol).


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26
y‘fA•ây‘fAƒƒfƒBƒG[ƒ^Œn‚ðŒÅ’艻‚µ‚½“±“d«–Œ‚ƃfƒqƒhƒƒQƒi[ƒ[ƒZƒ“ƒT‚Ö‚Ì“WŠJ

Î’ˏr”Ž*E¬”©‰p—EŽÂŒ´Š°–¾E’ôŽR‹`lE‘ŠàV‰v’j

ƒIƒŠƒGƒ“ƒ^ƒ‹“d‹C*E“ŒH‘åH

DEHYDROGENASE-NAD-MEDIATOR SYSTEM IN CONDUCTIVE MEMBRANE FOR AMPEROMETRIC DEHYDROGENASE SENSOR

Toshihiro ISHIZUKA, Eiri KOBATAKE, Hiroaki SHINOHARA, Yoshihito IKARIYAMA and Masuo AIZAWA

Department of Bioengineering, Tokyo institute of Technology
2-12-1 O-okayama Meguro-ku, Tokyo 152, Japan
Oriental Electric Co., Ltd.
3-9-7 Nobidome Niiza-shi, Saitama352, Japan

A mediator-coexisting dehydrogenase-NAD conductive polymer electrode was prepared for the demonstration of a versatile dehydrogenase sensor. This conductive enzyme membrane coated electrode worked as a lactate sensor in the applied potential at 0.38 V (vs. Ag/AgCl). On the other hand, the electrode worked as a pyruvate sensor at -0.1 V. To demonstrate the versatility of the electrom transfer system and of the equilibrium enzyme reaction, the determination of pyruvate and lactate with the same enzyme membrane electrode was performed.


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t2
ƒ}ƒCƒNƒƒAƒŒƒC“d‹É‚ð—p‚¢‚½ƒZƒ“ƒVƒ“ƒOƒVƒXƒeƒ€

“à“c@—EE––‰i’qˆê

“Œ–k‘åH

SENSING SYSTEMS USING MICROARRAY ELECTRODES

Isamu UCHIDA and Tomokazu MATSUE

Electrochemical characteristics of an interdigitated microarray electrode (IDAE) and an individually addressable microarray electrode (IAAE) were investigated in flowing streams. The IDAE showed amplification of current responses for electrochemically reversible species due to redox cycling and the responses were in good agreement with those predicted by the digital simulation. The IDAE was applied to the determination of catecholamines in a brain homogenate in HLPC. The IAAE having 16 microbands was applied to multichannel detection in FIA and HPLC. The current responses at each band held at a different potential were collected by a multipotentiostat to obtain three dimensional results.


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27
’†«—n‰t’†‚Å—˜—p‚Å‚«‚éL-ƒŠƒ“ƒSŽ_ƒZƒ“ƒT

…’J•¶—YE–‘ˆêEóˆä“¹•F

‘@‚Œ¤

L-MALATE SENSOR THAT CAN OPERATE IN NEUTRAL SOLUTIONS

Fumio MIZUTANI, Soichi YABUKI and Michihiko ASAI

Research Institute for Polymers and Textiles
1-1-4 Higashi Tsukuba, Ibaraki 305, Japan

An L-malate-sensing enzyme electrode has been constructed from an oxygen electrode and a layer containing immobilized malate dehydrogenase (MDH) and NADH oxidase. MDH catalyzes the oxidation of L-malate by NAD+:
MDH
@@@@L-malate@@+@@H+@@@@@@Ì@@@@@oxaloacetate + NADH + H+ (1)
The NADH formed is then oxidized by oxygen with the reaction:
NADH oxidase
NADH + O2 + H+@@¨@@NAD+ + H2O2 (2)
The NADH oxidase reaction, the elimination of NADH as well as the regeneration of NAD+, is effective for displacing the equilibrium of the MDH reaction to the right, which allows the efficient L-malate determination even in neutral media. L-Malate in the range of 5 ƒÊM - 2 mM is measured within 1 min at pH 8.1.


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28
ƒCƒIƒ“ŒðŠ·–Œ‚É‚æ‚éEEEƒZƒ“ƒT‚Ì”ñ“ÁˆÙ‰ž“š‚Ì—}§

ŽR“à@”ɁE–î”ö”mE•ÐŽR–¾G*E÷ˆä‚ ‚ä‚Ý*E‹g“c‘וF*E’ôŽR‹`l**

‘—§ƒŠƒnŒ¤E“Œ—m‘åH*E“ŒH‘åH**

INHIBITION OF NON-SPECIFIC RESPONSE OF ENZYME EMBODIED ELECTRODE (EEE) SENSOR BY NAFION FILM

Shigeru YAMAUCHI, Masashi YAOITA, Akihide KATAYAMA*, Ayumi SAKURAI*, Yasuhiko YOSHIDA* and Yoshihito IKARIYAMA**

Research Institute of National Rehabilitation Center
4-1 Namiki Tokorozawa, Saitama 359, Japan
*Dept. of Applied Chemistry, Faculty of Engineering, Toyo University
2100 Kujirai Kwagoe, Saitama 350, Japan
**Dept. of Bioengineering Tokyo Institute of Technology
2-12-1 O-okayama Meguro-ku, Tokyo 152, Japan

We fabricated a glucose sensing EEE sensor on a Nafion coated platinum black electrode to minimize non-specific responses to electroactive substances in blood such as acid. Anodic current of oxidation of ascorbic acid decreased with an increase in the concentration of Nafion in the coating solution. The response to ascorbate decreased to about 20% by an introduction of Nafion film, whereas that to glucose remained in the same order of magnitude, indicating selective inhibition of ascorbates. The EEE sensor with a Nafion coated platinum black gave a dynamic range to glucose in a concentration range from 10 ƒÊM to 10 mM, without deterioration by the introduction of the Nafion film.


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29
ƒyƒ‹ƒIƒLƒVƒ_[ƒ[ƒ‚ƒfƒ‹“d‹É(2) H2O2ƒZƒ“ƒT‚Æ‚µ‚Ẵwƒ€-ƒyƒvƒ`ƒh“d‹É

—§ŠÔ@“OE•Ÿ‰ª@ŽÀE“n•Ó@³

“Œ‘吶Œ¤

PEROXIDASE MODEL ELECTRODES-II
HEME PEPTIDE-MODIFIED ELECTRODE AS A REAGENTLESS H2O2 SENSOR

T. TATSUMA, M. FUKUOKA and T. WATANABE

Institute of Industrial Science, University of Tokyo
Roppongi Minato-ku. Tokyo 106, Japan

A peroxidase model electrode was devised for reagentless sensing of H2O2. A small model molecule, which mimics the vicinity of the reaction center of a redox enzyme, communicates electrochemically with an electrode. Heme nonapeptide (M. W. = 1630) exhibiting peroxidase activity was adopted as a peroxidase model, and was covalently immobilized on a tin oxide (SnO2) electrode as a roughly monomolecular layer. The electrode thus obtained can sense H2O2 at concentrations down to 1~10-6 M without electron mediator nor promoter, at a mild potential of +150 or +300 mV vs. Ag/AgCl. In a batch system, the output current reached a steady state in a few seconds. Measurements were performed also in a flow system with an assay time of 0.5-1.0 min/sample.


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30
ƒOƒ‹ƒR[ƒXƒIƒLƒVƒ_[ƒ[ŒÅ’艻 N-’uŠ·ƒ|ƒŠƒsƒ[ƒ‹”––Œ“d‹É‚̍쐻‚¨‚æ‚Ñ‚»‚̃Z ƒ“ƒT‚ւ̉ž—p

ˆÀàVŠ²lE¼‰ºLKE²’|@OE‹à•i¹ŽuEž­@Í

“¿“‡‘åH

FABRICATION OF THIN FILM ELECTRODE IMMOBILIZED GLUCOSE OXIDASE IN N-SUBSTITUTED POLYPYRROLE FILM AND ITS APPLICATION TO GLUCOSE SENSOR

Mikito YASUZAWA, Nobuyuki MATAUSHITA, Hiromu SATAKE, Syouji KANESHIMA and Akira KUNUGI

Department of Chemical Science and Technology, Faculty of Engineering, The University of Tokushima
Hinamijosanjima-cho, Tokushima 770, Japan

An effective glucose sensor was prepared from glucose oxidase (GOD) immobilized by electropolymerization of 1-pyrrole propionic acid (PPA). The characterization of GOD/PPPA/Pt electrlde was investigated by FIA system. A good linearity was obtained in the glucose concentration between 0.005-1 mg/ml.Response currents were influenced by PPA, GOD concentrations and deposition charge. Its sensitivity was stable for more than a month.


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31
y‘fŒÅ’艻ŠwCü“d‹É‚ÉŠî‚­V‚µ‚¢ƒAƒ“ƒyƒƒƒgƒŠƒbƒNƒRƒŒƒXƒeƒ[ƒ‹ƒZƒ“ƒT

’r“c@ME‘åâ•’j*E—é–Ø”ü‹IŽqE¬ŽR@¸

“Œ”_H‘åHE“ŒH‘呍‡—H*

NEW AMPEROMETRIC CHOLESTEROL SENSOR BASED ON IMMOBILIZED ENZYME CHEMICALLY MODIFIED ELECTRODE

Shin IKEDA, Takeo OHSAKA*, Mikiko SUZUKI aand Noboru OYAMA

Department of Applied Chemistry, Faculty of Technology, Tokyo University of Agriculture and Technology
Nakamachi Koganei, Tokyo 184, Japan
*Department of Electronic Chemistry, Graduate School at Nagatsuta, Tokyo Institute of Technology
4259 Nagatsuta Midori-ku, Yokohama 227, Japan

The characterization of an amperometric cholesterol sensor based on immobilized enzyme chemically modified electrode (IECME) was carried out. The IECME consisted of a bilayer film coating, the inner film was a cobalt tetrakis (o-aminophenyl) porphyrin polymer film with the capability of electrocatalytic reduction for O2, and the outer was a cholesterol oxidase (CHOx) film cross-linked by glutaraldehyde. The IECME showed a reproducible response for the addition of cholesterol solution, which depended on cholesterol concentration and on the amount of CHOx immobilized in the outer film. In this sensor system, the current response was unaffected by interferences (ascorbic acid, uric acid, etc.). It is proposed that the IECME is useful sa a solid-type amperometric cholesterol sensor.


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32
’E…‘fy‘fŒn-PCP“d‹É‚ð—p‚¢‚éƒoƒCƒIƒZƒ“ƒT‚ÌŠJ”­

Ä“¡@•*E—é–ؐ³NE–¯’J‰hˆêEŒy•”ª•v

‘å“ú–{ˆóü*E“Œ‘åæ’[Œ¤

DEVELOPMENT OF BIOSENSOR USING DEHYDROGENASE-PLATINISED CARBON PAPER (PCP) ELECTRODE

Takeshi SAITO*, Masayasu SUZUKI, Eiichi TAMIYA and Isao KARUBE

*Central Research Institute, DAI NIPPON PRINTING Corporation
Shinjuku-ku, Tokyo 162
Research Center for Advanced Science and Technology, University of Tokyo
Meguro-ku, Tokyo 153

A PCP-electrode has been known to have high catalytic activity and protein-absorption ability. A cyclic voltammogram of ƒÀ-NADH with bare PCP-electrode showed loose oxidation peak from +400 mV to +900 mV and current of 50 ƒÊA was obtained for 1 mM ƒÀ-NADH at +600 mV versus Ag/AgCl electrode. PCP absorbed about 0.04 unit/cm2 glucose dehydrogenase (GDH) and GDH-PCP electrode showed current response corresponding to glucose concentration. This electrode didn't respond to other several sugars and showed excellent selectivity to glucose.


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33
ŒŒ“œ’l‘ª’è—pƒfƒBƒXƒ|[ƒUƒuƒ‹ƒOƒ‹ƒR[ƒXƒZƒ“ƒT

‰ÍŒI^—ŽqE‹g‰ªr•FE“ìŠCŽj˜N

¼‰º“dŠí“dŽq‰ÈŠwÞ—¿Œ¤

DISPOSABLE GLUCOSE SENSOR FOR BLOOD SAMPLE

Mariko KAWAGURI, Toshihiko YOSHIOKA and Shirou NAKAI

Matsushita Electric Industrial Co., Ltd. Electrochemical Materials Research Lab.
Moriguchi, Osaka 570, Japan

A disposable glucose sensor which can be used at home to measure the glucose concentration in blood has been developed. With only a drop of blood (3 ƒÊl), the glucose concentration up to 25 mM can be determined within 60 seconds. The sensor has an enzyme reaction layer which is a mixture of a water-soluble polymer, an enzyme and a mediator on printed carbon electrodes. The electrodes are coated with carboxymethyl cellulose to remove the influence of blood cells. The sensor could be stored at 40Ž for more than 3 months with no change in the initial performance.


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34
ƒvƒƒgƒ““±“d«ŒÅ‘Ì“d‰ðŽ¿‚ð—p‚¢‚½y‘fƒZƒ“ƒT

–”‹g’¼ŽqEŽO‰Y‘¥—YEŽR“Y@úf

‹ã‘呍‡—H

ENZYME SENSOR USING PROTON-CONDUCTIVE SOLID ELECTROLYTE

Naoko MATAYOSHI, Norio MIURA and Noboru YAMAZOE

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

A solid-state glucose sensor using a proton-conductor thick-film was investigated as an approach to a miniaturized and integrated enzyme sensor. The sensor element was composed of the following electrochemical cell: (counter electrode) Au | antimonic acid thick-film (proton conductor) | Pt-GOD (sensing electrode). The antimonic acid thick-film (ca. 10ƒÊm) was formed on a porous alumina substrate by a spin-coating method. Glucose oxidase (GOD) was immobilized by applying carbon paste on the sensing Pt electrode. The emf of sensor varied logarithmically with a change in glucose concentration in the range from 3~10-3 to 6~10-2 M in a phosphate buffer solution of pH 7.0 at 30Ž, following Nernst's equation. The 90% response time was about 1 min. The glucose sensitivity was almost stable for 10 days.


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35
Œõƒtƒ@ƒCƒo[ƒOƒ‹ƒR[ƒXƒZƒ“ƒT

²“¡GsE•Ÿ“cô•vE’†ŽR@´

ŒÃ‰Í“dH‰¡•lŒ¤

OPTICAL-FIBER GLUCOSE SENSOR

Hideyuki SATO, Teruo FUKUDA and Kiyoshi NAKAYAMA

Yokohama Laboratories, The Furukawa Electric Co., Ltd.
2-4-3 Okano Nishi-ku, Yokohama 220, Japan

The glucose sensors using electrochemical and optical detecting methods were constructed by ourself, and the both characteristics of linear response against glucose concentration were elucidated.
In electrochemical system, the sensing element, which consisted of the film for passing selectively molecular oxygen and the glucoseoxydase film coated in order on platinum electrode, was employed. The observed current corresponding to the limiting current due to diffusion of dissolved molecular oxygen decreased linearly with increase in glucose concentration within 1~10-3 mol dm-3. In optical means, the film of the mixtures of glucoseoxydase-peroxydase-colorable material and the white film for passing selectively liquid, which were overlapped in series on the optical fiber, were the sensing part. The reflective absorbance indicated the linear dependence on glucose concentration in the range of 0-6~10-4 mol dm-3. The both glucose sensors turned out to possess the linear response at nearly same order level.


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36
Œõ“±”g˜H–@‚ð—˜—p‚µ‚½”÷¶•¨ƒZƒ“ƒT
\ƒOƒ‹ƒR[ƒXƒZƒ“ƒT‚̍\’z\

Œ´@–«“TE‹´–{˜amEˆÉ“¡Œö‹I*E‘º—ÑáÁs*E“¡“ˆ@º

“Œ‘åHE‰¡•l‘‘åŠÂ‹«Œ¤*

MICROBIALSENSOR UTILIZING OPTICAL WAVEGUIDE METHOD AN APPLICATION FOR A GLUCOSE SENSOR

Toshinori HARA, Kazuhito HASHIMOTO, Kiminori ITO*, Masayuki MURABAYASHI* and Akira FUJISHIMA

Department of Synthetic Chemistry, Faculty of engineering, Tokyo University
7-3-1 Honogo Bunkyo-ku, Tokyo 113, Japan
*Institute of Environment Science & Technology, Yokihama National University
Tokiwadai Hodogaya-ku,Yokohama 240, Japan

Application of optical waveguide method to an alchol microbial sensor was investigated.
General idia is as follows. Alchol, which is produced by immobilized microbials, cause the color enhancement of the photochromic materials. The change in absorbance is detected by optical waveguide system. We used WO3 as a photochromic material and S. cerevisiae as a microbe, and tried to construct a glucose sensor. Some experiments which testify the possibility of this system are described.


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37
ƒJƒr‹ÛŽ…‚̃oƒCƒIƒZƒ“ƒVƒ“ƒOƒVƒXƒeƒ€

Œà@Šî–PEŽR“c@‹Å*E‘‚@‹G“ì*EŸ“cC¶*E‘qàVŠì‹v•v*E‘q“c@_**E¼‰ª‰p–¾

“Œ”_H‘åHEƒoƒCƒI‹ZŒ¤*E“Œ‹žŒ°”÷‹¾‰@**

BIOSENSING SYSTEM OF FUNGAL HYPHA

Kibong OH, Satoru YAMADA*, Jinan CAO*, Osao SUMITA*, Kikuo KURASAWA*, Hiroshi KURATA** and Hideaki MATSUOKA

Department of Biotechnology, Tokyo University of Agriculture and Technology
2-24-16 Nakamachi Koganei, Tokyo184, Japan
*Research and Development Division, Bio-Giken Inc.,
1-5-8 Iwamotocho Chiyodaku, Tokyo 101, Japan
**The Tokyo Kembikyoin Foundation.
Kudanminami Chiyodaku, Tokyo 102, Japan

A useful system for the evaluation of antifungal activity has been developed based on the dynamic growth process of a single hypha. The newly developed system is composed of a reaction vessel under a microscope. CCD camera, TV monitor, VTR and a microcomputer. A fungus was inoculated in the reaction vessel and reacted with an antifungal reagent in the gas phase either in batch or flow reaction manner. The apex of a growing hypha displayed on TV monitor was followed automatically. The evaluation of some essential oil components was performed within several hours. Useful paramerters are presented for the quantitative expression of antifungal activity.


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38
”÷¶•¨ƒZƒ“ƒT‚É‚æ‚é—°‰»•¨‚ÌŒv‘ª

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DETERMINATION OF SULFUR COMPOUNDS BY MICROBIAL SENSOR

Izumi KUBO, Masako FURUSAWA*, Yoshiko ARIKAWA*, Isao KARUBE**, Takahiro KANAGAWA*** and Eiichi MIKAMI***

Institute of Life Science, Soka University
*Research Center for Advanced Science and Technology, University of Tokyo
**Japan Women's University, Faculty of Domestic Science
***Fermentation Research Institute, Agency of Industrial Science, MITI

Thiobacillus thioparus is a chemoautotrophic and aerobic bacterium, and oxidizes sulfur compounds to sulfuric acid. Biosensor for the determination of sulfur compounds concentration has been developed. It consists of an oxygen electrode and immobilized Thiobacillus thioparus membrane. The optimum condition to operate this sensor was pH 7.0, 30Ž. The concentration of sulfur compounds can be determined by the measurement of the current output of the oxygen electrode. This sensor was applied to the determination of thiosulfate and methylmercaptan. When it was applied to the thiosulfate determination in batch system, linear relation of the sensor was 1ƒÊM- 100ƒÊM, and output of the sensor was stable for 1 month. The response of the sensor to methylmercaptan depended on the concentration from 1 to 5 mM in flow injection system.


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