Vol. 15, Supplement B (1999)

Proceedings of the 29th Chemical Sensor Symposium
September 13-14, 1999

Abstracts

1.

d͔/|CIRvbNXdɂpoCIZT

ڍCKMVCN\

BIOSENSOR BASED ON THE COMPOSITE FILM ELECTRODE OF ELECTRODEPOSITED PLATINUM WITH POLYION COMPLEX

Masahiro Meguro, Takayuki Kuwahara, Tetsuya Osaka

Department of Applied Chemistry, School of Science and Engineering; Kagami Memorial Laboratory for Materials Science and Technology, Waseda University
Shinjuku-ku, Tokyo 169-8555, Japan

A glucose sensor based on a combination of electrodeposited platinum with polyion complex (PIC) containing glucose oxidase (GOD) formed onto platinum electrode was fabricated. This glucose sensor electrochemically detects H2O2 generated by an enzymatic reaction between glucose and oxygen, which is catalyzed by GOD, on the platinum electrode. The morphology of electrodeposited platinum in the PIC film observed by scanning electron microscopy (SEM) and the result of energy dispersive X-ray microanalysis (EDX) suggest that the electrodeposited platinum grew to lift the PIC layer. However, at some locations of the film, a composite structure of platinum and PIC was formed, in which platinum particles were widely dispersed in the vicinity of the enzyme molecules. This morphology enables the oxidation of H2O2 to be more effective, resulting in the improved performance of the glucose sensor.

To Japanese Contents To English Contents
2.

D-A~m_ILV_[[Œ艻|CIRvbNX̍쐻

CJYCcF

HZ@

PREPARATION OF POLYION COMPLEX MEMBRANE CONTAINING D-AMINO ACID OXIDASE

Soichi YABUKI, Fumio MIZUTANI and Yoshiki HIRATA

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

Polyion complex membrane containing D-amino acid oxidase was prepared from a mixture of poly-L-lysine, polystyrene sulfonate and enzyme solutions: the solutions were mixed on the glassy carbon electrode and the electrode was dried for 4 hrs. The enzyme electrode was used for the detection of D-amino acid by the measuring of oxidation current for hydrogen peroxide at the base electrode. When response to D-alanine (ALA) was measured, current response was proportional to the ALA concentration up to 0.5 mM, response time was ~30 s. Lower detection limit was 5 M of ALA. The electrode could be used as a biosensor for D-amino acid. Long-term stability of the enzyme electrode was examined: 40 days after the preparation, the response current became 1.2 times of the initial value. The phenomenon would be caused by the swelling the polymer with water.

To Japanese Contents To English Contents
3.

ϔMyfpISFET^oCIZTɂORVhZVO

؁@mAΊہ@YAѓc@g

ʑH

GLUCOSIDES SENSING BY ISFET BIOSENSOR USING MULTI-THERMOSTABLE ENZYMES

Kazuhito AOKI, Yoshihiro ISHIMARU, and Takeaki IIDA

Department of Functional Materials Science , Faculty of Engineering, Saitama University
255 Shimo-okubo, Urawa-shi, Saitama-ken 338-8570, Japan

An ion sensitive field-effect transistor (ISFET) was applied to the determination of glycosides. The pH-sensing gate of ISFET was covered with the immobilized thermostable enzymes using thermostable-D-glucosidase and thermophilic glucokinase. The -glucoside sensor responded to -glucosides such as salicin and esculin. The sensor exhibited higher thermostability than that of non-thermostable enzyme. The sensor also responded to lactose at pH 9.0 and 60 . However, at the pH of 7.0, it was found that the sensor was also able to respond to lactose at 50 . The ATP solution gradually decomposed to change the pH of the solution at the rate of about pH 0.1 for 3 days. Few differences were found within 9 days between ATP solution stored at 4 and another one freshly prepared at same pH.

To Japanese Contents To English Contents
4.

Con AƖCyfݐϖpoCIZT[

їRAď

k@

BIOSENSORS BASED ON MULTILAYER FILMS COMPOSED OF Con A AND UNMODIFIED ENZYMES

Yuka KOBAYASHI and Jun-ichi ANZAI

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

Enzyme multilayer films were prepared using Con A and glycoenzymes (GOx and HRP) without any chemical modification. The formation behavior of the multilayer film was studied by UV spectrophotometry and electrochemistry. The silylated quartz slide was immersed in a fluorescein-modified Con A solution and a GOx solution alternately. The absorbance, originating from the fluorescein moiety, increased in proportion to the number of deposition. The Con A/GOx multilayer film was prepared on the surface of Pt electrode. The response current to -D-glucose depended on the number of GO x layers deposited. These results show that constant amount of Con A and GOx were immobilized upon each deposition and enzyme films thus prepared are catalytically active. H2O2 sensors based on Con A/HRP multilayer films were also evaluated.

To Japanese Contents To English Contents
5.

dd@ɂyfŒdɂ̍쐻

VlETERcNE@́EM*

HEmH*

PREPARATION OF ENZYME-IMMOBILIZED ELECTRODES USING THE ELECTROPOLYMERIZATION METHOD

Mikito YASUZAWA, Shinji FUJII, Tetsuya YAMADA, Akira KUNUGI and Shinji IMAI*

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

New enzyme-immobilized electrode was prepared by electropolymerization of pyrrole derivatives having saccharide units, 1-(6-D-gluconamidohexyl)pyrrole (GHP), in the presence of glucose oxidase. The long-term stability of the obtained electrode was examined over 90 days and showed relatively constant response current from the first day of measurement. Moreover, the response currents of this electrode were approximately twenty times higher than that of the electrode obtained from 1-(3-D-gluconamidopropyl)pyrrole, which the distance between pyrrole groups and saccharide units are three methylene (-CH2-) groups less than that of GHP. The response current of the electrodes prepared from GHP was approximately not influenced by the addition of urea, D-(-)-fructose, asorbic acid,or acetaminophen. However, the influence of uric acid was not negligible.

To Japanese Contents To English Contents
6.

dvAZRGXe[[oCIZT\ẑ߂̃|s[̓dCwI

IK@tFhZ@A ΊۗYAѓcg

ʑH

ELECTROCHEMICAL FORMATION OF POLYPYRROLE FILM FOR CONSTRUCTION OF THE AMPEROMETRIC ACETYLCHOLINESTERASE-BASED BIOSENSOR

Olga V. FEDOSSEEVA, Yoshihiro ISHIMARU, and Takeaki IIDA

Department of Functional Materials Science, Faculty of Engineering, Saitama University
255 Shimo-okubo, Urawa-shi, Saitama-ken, 338-8570, Japan

Acetylcholinesterase (AChE) has attracted much attention because of its usefulness as a sensitive indicator of a normal nerve-muscle interaction. Acetylcholinesterase is a specific cholinesterase, hydrolyzing predominantly choline esters. This report deals with electrochemical formation of polypyrrole film for construction of the amperometric acetylcholinesterase-based biosensor. The cell with a stationary mercury film-covered electrode (SMFC) and the Pt auxiliary electrode as the polypyrrole modified electrode was used. The activity of immobilized acetylcholinesterase was determined amperometrically by SMFE using thioester as a substrate. The analytical characteristics of the polypyrrole-modified platinum electrode, including electrodeposition of the enzyme with and without the polypyrrole were studied. The diffusion of the enzyme through the polypyrrole film was analyzed electrochemically by comparison of the current responses obtained from the Pt/polypyrrole/AChE and Pt/AChE/polypyrrole electrodes, respectively. The optimal conditions for the fabrication of the Pt black layer on the platinum electrode, and the characteristics of the resulting electrode were also investigated.

To Japanese Contents To English Contents
7.

VLT|}[𗘗pAygbNOR[XZT

JYAAѓY

H

AMPEROMETRIC GLUCOSE SENSOR USING A SILOXANE POLYMER LAYER

Fumio MIZUTANI, Soichi YABUKI, and Seiichiro IIJIMA

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

An amperometric glucose-sensing electrode based on the cathodic detection of oxygen consumption during the glucose oxidase (GOx) reaction was prepared as follows. A platinum electrode was modified with polydimethylsiloxane (PDMS), and a GOx-layer was placed on the PDMS layer. The oxygen permeability and hydrohobic property of the PMDS layer made it possible to monitor the oxygen consumption rate without interference from the hydrogen peroxide. The concentration of glucose (0.01-1.2 mM) could be determined from the decrease in the cathodic current at -0.1 V vs. Ag/AgCl, without any interference from uric acid and acetaminophen.

To Japanese Contents To English Contents
8.

sm[XILV_[[[UJpt[AygbNoCIZV O

@jAr@^A{@Y

_ސHȑw

FLOW-AMPEROMETRIC BIOSENSING WITH USE OF A PYRANOSE OXIDASE COLUMN

Ikuo SATOH, Shinjou KOIKE, and Masaichiro HASHIMOTO

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

Pyranose oxidase from Coriolus versicolor covalently immobilized on porous glass beads was tested as a recognition element for determination of D-glucose. The amperometric FIA system was assembled with a column containing the immobilized enzymes mounted in a water-jacketed holder and a polarographic oxygen electrode in a flow-through cell. Variations in oxygen levels at the outlet of the column was successively monitored and used as the measure of the catalytic activity. The responses attributable to consumption of dissolved oxygen were observed by injecting the substrate solutions. A calibration graph was obtained between up to 2.0 mM of the substrate solutions and decreases in dissolved oxygen. Although the column was used at room temperature for about 5300 assays during two years and three months, it showed significantly well operational-stability.

To Japanese Contents To English Contents
ʍu

dCw}CNZT-̓foCX̔]_oȊwւ̉p

OH@CA@c

NTTAmssb

APPLICATION OF ELECROCHEMICAL MICROSENSORS AND ANALYTICAL DEVICES FOR NEUROSCIENCE

Osamu NIWA and Keiichi TORIMITSU

NTT Lifestyle and Environmental Technology Laboratories, NTT Basic Research Laboratories
3-1, Morinosato, Wakamiya, Atsugi, Kanagawa 243-0198, Japan

The direct observation of neurotransmitters is extremely important as regards studying the signal transmission mechanism between individual nerve cell. Various microsensors including microelectrodes, enzyme modified electrodes, on-line sensors have been developed for real time-measurement of neurotransmitters. In this article, the electrochemial microsensors and analytical devices used for in vivo and in vitro analysis of neurotransmitters are reviewed. @

To Japanese Contents To English Contents
܍u.

̋@\qCdɂ̍쐻ƃoCIZTւ̉p

JY

H

PREPARATION AND USE OF ELECTRODES MODIFIED WITH BIOFUNCTIONAL MOLECULES

Fumio MIZUTANI

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

Biosensors combining the specificity of biological reactions with electrochemical signal transduction have attracted increasing interest in the last two decades. Particular efforts in this field have recently been directed to the establishment of simple, rapid and reproducible procedures for constructing biosensors. Techniques for preparing chemically-modified electrodes (CMEs) are useful for this purpose. This paper focuses upon our research results for the preparation of biosensors of CME-type; the use of biochemically- or chemically-modified proteins, and that of polyion complex membranes as enzyme matrices or anti-interference layers are described.

To Japanese Contents To English Contents
9.

R̗ݐϖ̍R̉

Ė؁@Ga@A@FT@Aā@

k@

ANTIGEN-BINDING PROPERTY OF ANTIBODY MULTILAYER

Hidekazu Saiki, Tomonori Hoshi, and Jun-ichi Anzai

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

Spatially ordered multilayer films of antibody were prepared by a layer-by-layer deposition of avidin and biotin-labeled antibody on the surface of quartz slide. The deposition behavior of the multilayer films was monitored spectrophotometrically using dye-labeled avidin or directly from the absorbance of the proteins. The spectrophotometric date showed that the antibody and avidin can be built into spatially ordered multilayer structure by the layer-by-layer deposition. The antibody retained the binding activity in part to the antigen: only the outermost 3 or 4 layers of antibody exhibited the binding activity. A further improvement will be needed to develop the multilayer films in which the antibody fully exhibits binding activity.

To Japanese Contents To English Contents
10.

}CN_fdɂɂSpO2̑

ؔ́AnӈFAerC*

}g啨HA_ȐH*

MEASUREMENT OF pO2 USING A MICROMACHINED OXYGEN ELECTRODE

Hiroaki SUZUKI, Ikutomo WATANABE, and Yuji KIKUCHI*

Institute of Materials Science, University of Tsukuba
1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan
*National Food Research Institute
2-1-2 Kannondai, Tsukuba, Ibaraki 305-8642, Japan

A micromachined Clark-type oxygen electrode was used to measure pO2 in whole blood. A cathode and an anode were formed on a glass substrate by photolithography. A micro container for the electrolyte solution was formed on a silicon substrate using anisotropic etching. A slicone rubber gas-permeable membrane was formed on the sensitive area. Four types of oxygen electrodes with cathodes whose dimensions ranged from 200 m to 500 m were fabricated. Good linear calibration curves were obtained. In using samples of small volumes, however, the consumption of oxygen by the oxygen electrode itself posed a problem. An influence is the dependence of the output current on stirring. By using a smaller cathode, the influence could be reduced. The oxygen electrode was used to measure pO2 in whole blood. The obtained pO2 values were fairly close to those obtained by a commercial blood gas analyser.

To Japanese Contents To English Contents
11.

_fdɂptLVuoCIZT[̊J

J{qu*A x*A ˏ~T**A {no**AX**A a*A r܈T**A Oэ_*A yv**

CH*E[**

DEVELOPMENT@OF@A@FLEXIBLE@BIOSENSOR USING@A@FILM|TYPE@OXYGEN@ELECTRODE

Satoshi TANIMOTO*, Daisuke MUROTOMI*, Atsunori HIRATSUKA**, Hirotaka MIYACHI**, Satoshi SASAKI**, Kazuyoshi YANO**, Kazunori IKEBUKURO**, Kohji MITSUBAYASHI*, and Isao KARUBE**

*Department of Electrical Engineering, School of Engineering, TOKAI University
1117 Kitakaname Hiratsuka-shi, Kanagawa 259-1292, Japan
**Research Center for Advanced Science and Technology, The University of Tokyo
4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan

A flexible biosensor was constructed by immobilized glucose oxidase using photocrosslinkable poly(vinyl alcohol) onto a sensitive area of a film-type oxygen electrode, which was fabricated by sealing electrolyte solution (0.1mol/l KCl) by both gas- and non-permeable weldable membranes with Pt- and Ag/AgCl-coated electrodes. The amperometric biosensor was evaluated by measuring the reduction current of dissolved oxygen consumed by the enzymatic reaction of glucose oxidase using a computer controlled potentiostat with A/D converter. The device was linearly related to the glucose concentration over range of 0-1.381 mmol/l, with a correlation coefficient of 0.998. The flexible biosensor (thickness: 0.153 mm) is well suited for non-invasive detection of glucose or other analytes in biological fluids, such as tears, sweat, airway mucus, and saliva.

To Japanese Contents To English Contents
12.

Fe2+E|CIRvbNX핢dɂɂNOZVO

tRNAVvj

HE@@

NO SENSING USING Fe2+ / POLYIONCOMPLEX COVERED ELECTRODE

Tetsuya HARUYAMA, Masuo AIZAWA

Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology
Nagatsuta, Midori-ku, Yokohama 226-8501, Japan

Electrochemical NO sensing system has been developed using 1,4,8,11-tetraaza cyclotetradecane (cyclam)-F3(II)complex. NO+ was found to be electrochemically oxidized through cyclam-Fe(II)-NO+ on an electrode. For assembling an electrochemical sensor for NO, cyclam-Fe(II) was immobilized on an Pt electrode by poly-histidine / poly stylene complex. NO was determined in the concentration range from 0.1 uM to 30 uM, when the electrode potential was controlled at -100 mV vs. AgAgCl.

To Japanese Contents To English Contents
13.

Cɑ΂ȂII򉻍p

쎛 Cؑ tFC u*

HCoϑo*

SELECTIVE PURIFICATION ABILITY OF PLANT FOR INDOOR AIR-POLLUTANTS

Takeshi ONODERA, Haruhiko KIMURA and Takashi OYABU*

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

Purification characteristics of Epipremnum aureum (Golden pothos) for formaldehyde, toluene and xylene are examined, and the characteristics for mixture gas of formaldehyde and toluene or xylene are also examined using two kinds of gas sensors. Thy are a combustible gas and ammonia sensors. As results, {\it Epipremnum aureum} has high purification ability to formaldehyde, and has low ability to toluene and xylene. In the mixture gas, same characteristics are derived >from some experiments. Thus, Epipremnum aureum has an ability of selective purification for formaldehyde.

To Japanese Contents To English Contents
14.

AfqhKXpoCIZT̊J

R_A{SAOэ_

CH

DEVELOPMENT OF A GAS-PHASE BIOSENSOR FOR ALDEHYDE CHEMICALS

Yoshihiro NAKAYAMA, Yuki HASHIMOTO and Kohji MITSUBAYASHI

Deptment of Electrical Engineering, School of Engineering, TOKAI University
1117 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan

A gas-phase biosensor for aldehyde chemicals was constructed using an immobilized aldehyde dehydrogenase (ALDH) enzyme electrode and a flow reaction cell with both gas- and liquid-phase compartments separated by a porous diaphragm membrane. The output signal of the ALDH biosensor with a flow injection system was found to@be used measure acetaldehyde in the liquid phase over the range 0 to 3.0 mmol/l, with correlation coefficient of 0.996. The has-phase biosensor can be detected gaseous acetaldehyde and the sensor output was found to be related to the acetaldehyde concentration in the gas phase. Potential applications of the aldehyde gas-sensor include the analysis of the aldehyde compounds and an environmental assessment.

To Japanese Contents To English Contents
15.

gA~poCIZT̊J

{SAR_AOэ_

CH

DEVELOPMENT OF A BIOSENSOR FOR TRIMETHYLAMINE

Yuki HASHIMOTO ,Yoshihiro NAKAYAMA and Kohji MITSUBAYASHI

Deptment of Electrical Engineering, School of Engineering, TOKAI University
1117 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292, Japan

"Fish-odor syndrome" is a human disorder characterized by an impaired ability to convert the malodorous TMA to its odorless N-oxide. In human, TMA is metabolized exclusively to TMAO excreted in the urine. Fiavin-containing monooxygenase 3 (FMO3) has been reported to catalyze the majority of TMAO formation in vivo. The trimethylamine biosensor was constructed using a commercially available dissolved oxygen sensor with both FMO3 and Glucose-6-phosphate dehydrogenase (G6PDH) immobilized membranes. FMO3 was shown to catalyze an NADPH-dependent oxygenation of trimethylamine, and G6PDH was then used for the NADPH-generating system. The current decrease of the FMO3 immobilized biosensor was found to be linearly related to the trimethylamine concentration over the range 0 to 150 mmol/l, with a correlation coefficient of 0.992. Potential applications of the trimethylamine sensor include the diagnosis of "Fish-odor syndrome" and the evaluation of fish freshness.

To Japanese Contents To English Contents
16.

x␳@\p^roqZT̊J

oAORARɁARl

n

DEVELOPMENT OF SMALL-SIZED SPR SENSOR HAVING THERMAL COMPENSATING MECHANISM

Akira OHIDE, Shigeru TOYAMA, Shigeru YAMAUCHI, and Yoshihito IKARIYAMA

Research Institute, National Rehabilitation Center for the Disabled
4-1 Namiki, Tokorozawa, Saitama 359-8555, Japan

Stabilization method of SPR signal fluctuation due to thermal change has been examined. Here, an experimental SPR setup, where a thermistor was embedded in the stainless holder of the flow through cell attached to the sensor, was newly fabricated. The temperature was artificially changed during continuous measurements. The correlation between the cell temperature and the resonance angle was better than that of the chamber temperature. The fluctuation of the resonance signal was explained in terms of the change in the refractive index of the solution.

To Japanese Contents To English Contents
18.

A|yf@ɂ鈟(U)CI̔ʌv

@jAL@MqA@Sq

_ސHȑw

MICRODETERMINATION OF ZINC(II) IONS BASED ON THE APOENZYME REACTIVATION METHOD

Ikuo SATOH, Takako ARIGA, and Yumiko SATOH

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

Alkaline phosphatase immobilized onto porous glass beads was packed into a small polymer column and then used as a recognition element for zinc(II) ions in flow streams. The sensing system was assembled with the column housed in a water-jacketed holder and a quartz flow-through cell attached to a UV/VIS monitor. The catalytic activity was assessed by injecting 0.1 ml of 2 mM p-nitrophenyl phosphate(pH 8.0). The column could be regenerated by introducing 100 mM 2,6-pyridine dicarboxylate solution to remove zinc(II) ions complexed in the active site of the enzyme molecules. Submicromolar levels in zinc(II) ions were photometrically determined through its reactivation of the apoenzyme, i.e. ,metal-free enzyme. Performance of the system was examined.

To Japanese Contents To English Contents
19.

qX^~dɂ̊JƔ얞זẼqX^~Vւ̉p

@FAAˌhB

R

DEVELOPMENT OF A HISTAMINE-SENSITIVE MEMBRANE ELECTRODE AND ITS APPLICATION TO THE DETERMINATION OF HISTAMINE RELEASE FROM MAST CELLS

Takashi KATSU and Hiroki HIRODO

Faculty of Pharmaceutical Sciences, Okayama University
Tsushima, Okayama 700-8530, Japan

We developed a histamine-sensitive membrane electrode using prothiofos (O-(2,4-dichlorophenyl) O-ethyl S-propyl phosphorodithioate), an agricultural chemical, as a membrane solvent and sodium tetrakis[3,5-bis(2-methoxyhexafluoro-2-propyl)phenyl]borate as an ion-exchanger in a poly(vinyl chloride) membrane matrix. This electrode exhibited a near-Nernstian response to histamine in the concentration range 5 * 10-5 - 1 * 10-2 M with a slope of 56 mV per concentration decade in a physiologically balanced salt solution containing 154 mM NaCl, 2.7 mM KCl, 0.9 mM CaCl2, 5.6 mM glucose and 10 mM 4-(2-hydroxyethyl)-2-piperazineethanesulfonic acid (HEPES)-NaOH (pH 7.4). The limit of detection was 2 * 10-5 M. We used this electrode to determine histamine release from mast cells. The histamine concentrations determined with the histamine electrode agreed well with those determined by an established fluorimetric assay.

To Japanese Contents To English Contents
20.

YfmΏۂƂ艻WRjAƎ_dɂgݍ킹dʌ^ZT

Α׈Am]AOYY*ARY@f

@HA[Z*

MIXED-POTENTIAL TYPE SENSOR BASED ON STABILIZED ZIRCONIA AND OXIDE ELECTRODE FOR THE DETECTION OF HYDROCARBONS

Taiichi SHIRAISHI, Kengo SHIMANOE, Norio MIURA* and Noboru YAMAZOE

Graduate School of Engineering Sciences, Kyushu University
*Advaced Science and Technology Center for Cooperative Research, Kyushu University
Kasuga-shi, Fukuoka 816-8580, Japan

By using an oxide sensing electrode, a stabilized-zirconia based sensor was developed for the selective detection of hydrocarbons at high temperature. Among the fourteen kinds of oxides tested, CdO was found to be best suited for the sensing electrode of a tubular zirconia device, giving selective and quick response to C3H6 in air at 600C. The EMF value of the device was almost linear to the logarithm of C3H6 concentration in the range 50-800 ppm. The cross sensitivities to the other gases, such as CH4, C2H4, C2H4, C3H8, H2, CO, NO and NO6, were small or insignificant. Furthermore, a compact planar device (probe-type), which required no reference gas, was also fabricated. The C3H6 sensitivity of the planar device was found to be little influenced by a change in oxygen concentration in the sample gas. A sensing mechanism involving mixed potential was confirmed based on the measurments of polarization curves.

To Japanese Contents To English Contents
21.

ő̓d^KXZT̎vZbVOƉ

zAc@

HH

SOLID-ELECTROLYTE THICK-FILM GAS SENSOR PREPARED BY SOL-GEL METHOD

Youichi SHIMIZU* and Takeshi SODA

Department of Applied Chemistry, Faculty of Engineering, Kyushu Institute of Technology
Tobata, Kitakyushu 804-8550, Japan

A planar-type solid-state electrochemical gas sensor using an Na-ion conductor (NASICON) thick-film and a perovskite-type thin-film electrode could be prepared by novel sol-gel methods using aqueous complex and/or polymer - based precursors. NASICON thin-film could be fabricated onto alumina substates by spin-coating a tartaric acid - based gel, drying at 150 C, and sintering at 1000 C for 3h. Preparation of perovskite-type oxide thin-films at 500 C was also developed by the use of PVA - acetylacetone polymer precursor. The sensor device combined with LaNiO3 and NASICON thin-film showed high sensitivity to CO2 at 300-400 C. The 90% response time to 1000 ppm CO2 was as short as 10-30s at 300-400 C.

To Japanese Contents To English Contents
22.

Au-Li2CO3-La2O3mɂɗpCO2ZT

rJ񑬁AF

ijgN}@

CO2 sensor using Au-Li2CO3-La2O3 as detecting electrode

Hirotoshi IKEYA, Mitsuhiko MATSUI

Tokuyama Corp.
2023-1 Endo,Fujisawa-city Kanagawa 252-0816, Japan

Until now, it has been hard to obtain sufficient properties in the solid state CO2 gas sensor. This is because of its low humidity resistance of alkali metal carbonates used as the detecting electrode. In order to improve the humidity resistance, rare-earth metal oxide such as La2O3 is added into lithium carbonate with mixing ratio of the two substances being 1:10. This sensor exhibits fairly good sensing properties when it is laid under high humidity atmosphere.

To Japanese Contents To English Contents
23.

XΑw}^_fZT̍Zx_f͋C

CsAєAti*A[s*Ap*

v튔ЁEЖLc*

CHARACTERISTICS OF AN OXYGEN SENSOR WITH THE GRADED LAYER ELECTRODE IN HIGH-CONCENTRATION OF OXYGEN GAS.

Tatsuyuki OKUNO, Motoaki IIO, Tadashi INABA, Keiichi SAJI and Hideaki TAKAHASHI

Yazaki Meter Co., Ltd. Gas Equipment Development Department
Tenryu, Shizuoka 431-3393, Japan
Toyota Central R&D Labs., Inc. Electric Device Division
Nagakute, Aichi 480-1192, Japan

We developed a limiting current type oxygen sensor using sputtered ZrO2 and Pt thin film, and turned the sensor to practical use. In addition, the sensor was improved for stability by inserting a Pt/ZrO2 graded layer between the Pt electrode and the ZrO2 electrolyte. In this study, the graded layer of the sensor was fabricated by HELICON sputtering equipment, and the stability of the sensor performance was investigated in high oxygen atmospheres. Dureing an intermittent ON(1hr)-OFF(1hr) operation of 250cycles, the sensor showed stable I-V characteristics even in 90%O2/N2 mixture. From the durability test and SEM observations,it has been found that the sensor with graded layer electrode has high durability for operations in high oxygen atmospheres, and a large deterioration of the electrode-electrolyte interface of this sensor does not occur.

To Japanese Contents To English Contents
25.

A~m𑤍ɗL鍂qpQCM^SO2KXZT̊J

ʈ_AMAY

QH

QCM-TYPE SO2 GAS SENSOR USING A POLYMER WITH AMINO GROUP

Koji TAMAI, Masanobu MATSUGUCHI, and Yoshiro SAKAI

Department of Applied Chemistry, Faculty of Engineering, Ehime University

QCM-type SO2 gas sensor was prepared using poly(styrene-co-chloromethyl styrene) derivatives. Three kinds of diamino compounds, such as DMEDA, DMPDA, and DPEDA, were intorduced in the copolymer as the SO2 sorption site. The response time of the sensors were affected by the kind of amino group as well as the measuring temperature. Among them, the sensor containing DPEDA had the shortest response time and the good reproducibility, while the sensitivity was the lowest.

To Japanese Contents To English Contents
26.

et^VAjNO2KX

V@ANVA㌒iAn粌

Ñdq

NO2 GAS RESPONSE CHARACTERISTICS OF VARIOUS METAL PHTHALOCYANINE THIN FILMS

Tadashi NAGASAWA, Yasuyuki OHBACKenji MURAKAMI and Kenzo WATANABE

Research Institute of Electronics, Shizuoka University
3-5-1 Johoku, Hamamatsu, Shizuoka 432-8011, Japan

In order to realize a high sensitive NO2 gas sensor, thin films of several metal phthalocyanines (MPcfs) have been deposited on a glass substrate by the vacuum sublimation method. Effects of the central metals in the MPc molecules have been investigated on the gas-sensing characteristics for those thin films. It was found that the conductivity and sensitivity of MPc films are closely related to an oxidation potential of the MPc materials themselves. Response characteristics to the NO2 gas ambience also vary with the films. AFM studies reveal that the response characteristics are influenced greatly by the shape and microstructure of the films.

To Japanese Contents To English Contents
27.

A~t^VAj̏dNO2KX

RvqA㌒iAn粌

Ñdq

POLYMERRIZATION AND NO2 GAS RESPONSE CHARACTERISTICS OF Al-PHTHALOCYANINE THIN FILMS

Kumiko HIRAYAMACKenji MURAKAMI and Kenzo WATANABE

Research Institute of Electronics, Shizuoka University
3-5-1 Johoku, Hamamatsu, Shizuoka 432-8011, Japan

Sensing properties of Cu-phthalocyanine thin film-based NO2 gas sensor are strongly related to the film microstructures. We have tried to control the microstructures through a polymerization of source materials. Relations between the film microstructures and the NO2 gas sensing properties have been investigated precisely for the polymerized Al-phthalocyanine thin films.

To Japanese Contents To English Contents
28.

Iwɂ艻}M-I-SiC_CI[h̐fm

^AȏƐ

ΊC嗝H

HYDROGEN SENSING PROPERTY OF M-I-SiC DIODE STABILIZED BY INSULATOR LAYER

Shinji NAKAGOMI and Terunobu AZUMA

School of Science and Engineering, Ishinomaki Senshu University
Ishinomaki 986-8580, Japan

Electrical characteristics of MS and MIS diodes based on catalytic metal and silicon carbide structure in hydrogen and oxygen ambient were compared before and after high temperature operation process. MS type diode suffered a large change in current-voltage property. MIS structure seems to be better for the stability. The sensitivity of the MIS device to low concentration hydrogen was studied in region to 300. The voltage response to hydrogen was measured under a constant current. It has a good responsibility and reproducibility even to a few ppm hydrogen. The hydrogen sensitivity at lower concentration was increased with an decrease in operating temperature. Hydrogen sensitivity was decreased with increasing coexistent oxygen gas.

To Japanese Contents To English Contents
29.

_p鉷x[NOxm\ȐVeʌ^ZT

ΌBȁAqaAGׁAcS

CAPACITIVE TYPE GAS SENSOR FOR SIMULTANEOUS DETECTION OF TEMPERATURE AND NOx GAS CONCENTRATION

Tatsumi Ishihara, Kazumi Kamakura, Hiroyasu Nishiguhci, and Yusaku Takita

Department of Applied Chemistry, Faculty of Engineering, Oita University
Dannoharu 700, Oita 870-1192, Japan

Simultaneous detection of gas and temperature by the same sensor element was investigated. Since the capacitance and resistance of the oxide are independent theoretically, gas concentration and temperature were detected by capacitance and resistance. Large part of the investigated oxide exhibited a change not only in capacitance but also in resistance. Among the investigated mixed oxides, capacitance and resistance of 20SrSnO3-80Fe2O3 were only affected by NOx concentration and temperature respectively. Therefore, simultaneous detection of NOx and temperature became possible by using capacitance and resistance of this mixed oxide.

To Japanese Contents To English Contents
30.

WO3łSO2̋zSO2KXm

iAANA]@

H

SO2-ADSORPTION BEHAVIOR AND SO2-SENSING PROPERTIES OF WO3

Naoki MATSUNAGA, Takeo HYODO, Yasuhiro SHIMIZU and Makoto EGASHIRA

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

The sensitivity of various metal oxides to 800 ppm SO2 balanced with air has been investigated.@SnO2 and In2O3-5 mol% MgO exhibited a resistance decrease upon exposure to SO2 at 100 , whereas a resistance increase at 200300 .@However, the sensitivities calculated from both resistance changes were relatively small.@WO3 also exhibited a resistance increase upon exposure to SO2 at 400 , whereas a resistance decrease at 600 .@The resistance changes were largest among the metal oxides tested.@A.c. impedance measurement revealed that the resistance measured under a d.c. voltage was dominated by the grain boundary resistance.@From the TPD spectra of SO2 and O2 from WO3 subjected to SO2-preadsorption at different temperatures and the resistance changes during the TPD measurement, it was anticipated that SO2- was formed at different adsorption sites from those for oxygen at 400 .@At 600 , however, it was suggested that O2- species on the surface was substituted for by SO4- or SO3-, in addition to the consumption of them by the reaction with SO2.

To Japanese Contents To English Contents
31.

SnO2̂̃KXx̎xˑ

v@A˕v

VRXXd@

DEPENDENCE OF GAS SENSITIVITY ON HUMIDITY IN SEMICONDUCTOR SENSOR

Takashi KUSE , Sachio TAKAHASHI

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

The effects of humidity on gas sensitivity of SnO2, In2O23 and ZnO thick film sensors with different thicknesses of 30,100 and 200m, were investigated. The long span effect of humidity on gas sensitivity was investigated in detail. Further, the relationship between the humidity effect and the sensor temperature was investigated. It is expected that these findings are useful for design of sensor structure reducing the effects of humidity on gas sensitivity.

To Japanese Contents To English Contents
ʍu

C݂KXZT̐VWJ

@B

tBKZ

DEVELOPMENT OF GAS SENSORS FOR AIR QUALITY

Takeshi NAKAHARA

FIGARO ENGINEERING INC.,
1-5-11, Senbanishi, Minoo-Shi, Osaka 562-8505, Japan

Novel gas sensors for air quality were developed and put in the practical use in various applications. (1) Semiconductor gas sensor for auto-damper control system: SnO2 and WO3 were adopted as sensing materials to detect exhaust gases from gasoline and diesel vehicles. The sensing unit incorporated with a signal processing software showed good performance in damper control. (2) Semiconductor gas sensor for VOC detection: WO3 as a sensing material showed high sensitivity to volatile organic compounds such as toluene and xylene.
(3)Solid electrolyte CO2 sensor:CO2 sensor composed of NASICON iNa3Zr2Si2PO12jas a solid electrolyte and Li2CO3 as an auxiliary electrode was developed. Combining the sensor and a signal processing software made possible to monitor the CO2 concentration in an office precisely.

To Japanese Contents To English Contents
R܎܍u

d^dCwKXZTɊւ錤

Βn@O

v튔

A STUDEY ON THE AMPEROMETRIC GAS SENSOR USING ELECTROLYTIC SOLUTION

Toru ISHIJI

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

Amperometric gas sensors based on electrode reactions of gases are attractive for detection of various kinds of gases. I have investigated to realize a reliable gas detection by means of gas permeable electrode/electrolytic solution cell system. An amperometric sensor using a gold thin-film electrode showed good selectivity for arsine against coexisting solvent vapors. Sensitivity and reliability of HF sensor have been improved by a study of the electrolytic solution composition. New carbon dioxide and ammonia gas sensors have been developed by means of pH dependent metal oxide electrode reaction. A hand made oxygen gas sensor has been developed to arouse scientific interest for young students as an educational equipment.

To Japanese Contents To English Contents
32.

_̂punbZT̊J

p딎, RΈ, qj, VFu, Rq*, 쏹**, 쐭***, Rc_****

xRHƋZpZ^|ExRH*ER|Z**EkdCH***EmH****

DEVELOPMENT OF METAL-OXIDE SEMICONDUCTOR SENSORS FOR DETECTION OF VOC.

Masahiro Kadosaki, Shigekazu Yamazaki, Takasi Terasawa, Satoshi Fujiki Chiei Tatsuyama*, Masanori Hoshino**, Masayoshi Minami*** and Hiromi Yamada****

Toyama Industorial Technology Centor, 383 Takada,Toyama 930-0866, Japan
*Faculty of Engineering, Toyama Univesity, 3190 Gofuku,Toyama 930-8555, Japan@
**Cosel Co.,Ltd., 1-6-43 Kamiakae,Toyama 930-0816, Japan
***Hokuriku Electric Ind.Co.,Ltd., 3158 Shimo-okubo,osawano,Toyama 939-2292, Japan
****Toyo Kako Co.,Ltd., 1350 Shimo-umezawa, Namerikawa, Toyama 936-0857, Japan

Recently, the number of people taken ill in new house by indoor-air pollution, is steadily increasing. The phenomenon is what is called "sick house syndrome". Mostly it is caused by formaldehyde and VOC (Volatile Organic Compound) included in adhesive or paint. To develop a semiconductore type VOC sensor, a work was carried out for exploring high sensitive oxide semiconductor materials to formaldehyde, xylene, toluene. Among 23 metal oxides examined, SnO2, WO3, In2O3, ZnO, Co3O4 and Cr2O3 showed relatively high sensitivity. Also, the sensing property of SnO2 element to formaldehyde was extremely improved by addtion of Ag, but the sensors had short lifetime. In this work, in order to improve the sensitivity to VOC in air using another additive, the VOC sensing properties of SnO2 loaded with metal oxides are investigated. Among the 14 metal oxides loaded, MnO2 was found to be the most effective promoter for the SnO2-based sensors. The addition of 3 wt%MnO2 enhances the sensitivity to 100 ppm formaldehyde in air by about two order of magnitude at 200

To Japanese Contents To English Contents
33.

̎jICZT̋C@ւ̉p

͌qA]qAhAˌ׍OA@BAi@i

tBKZ

APPLICATIONS OF SEMICONDUCTOR ODOR SENSOR TO AIR CLEANERS

Tomohiro KAWAGUCHI, Eriko MIZUNO, Eijyu YOKOO, Yasuhiro SETOGUCHI, Takeshi NAKAHARA and Susumu YASUNAGA

Figaro Engineering Inc,
1-5-11 Senbanishi, Minoo-shi, Osaka 562-8505, Japan

In order to operate air cleaners automatically, the demand for gas sensors that can detect various odors at high sensitivity has increased. In this study we investigated two types of new gas sensors. "Sensor A(TGS2602)" exhibited high sensitivity to several volatile organic compound gases, and was effective to detect building material odors, such as varnish, wood adhesive and wood preservatives. On the other hand, "Sensor B(under development)" exhibited high sensitivity to sulfur and nitrogen compound gases, and was effective to detect offensive odors, such as kitchen garbage, toilet smells and so on. Furthermore, as these sensors exhibit low sensitivity to odorless gases, such as H2, they can monitor the effect of deodorization as compared to usual sensors(TGS2600) when an air cleaner is operated.

To Japanese Contents To English Contents
34.

WGgLVWVVŕ\ʉwPdyPt/SnO2̃KXo

acC]@*

ۍCH*

GAS-SENSING PROPERTIES OF Pd- AND Pt-LOADED SnO2 SUBJECTED TO SURFACE CHEMICAL MODIFICATION WITH DIETHOXYDIMETHYLSILANE

Department of Chemistry and Biotechnology, Sasebo National College of Technology
1-1 Okishin-cho, Sasebo-shi, Nagasaki 857-1193, Japan
*Department of Materials Science and Engineering, Faculty of Engineering, Nagasaki University
1-14 Bunkyo-machi, Nagasaki-shi 852-8521, Japan

Effects of Pd- or Pt-loading on the gas-sensing properties of SnO2 subjected to repeated surface chemical modification with diethoxydimethylsilane (DEMS) have been investigated in relation to the variations in temperature programmed desorption (TPD) of oxygen and in catalytic oxidation activity. Pt-loaded SnO2 was superior to Pd/SnO2 in H2-sensing, and the H2 sensitivity increased markedly, accompanied by an increase in H2 oxidation activity, with repeated surface modification. On the other hand, Pd/SnO2 was superior to Pt/SnO2 in CH4-sensing, and the modification for three times resulted in the maximum sensitivity of S=38 at 400C. Response and recovery characteristics of the CH4-sensing were satisfactory at 400C. However, the sensitivity decreased with further modification, although the catalytic activity was not so much influenced by the modification in accordance with the almost unchanged amount of PdO species measured by TPD. Anyway, the Pd/SnO2 sensor subjected to modification with DEMS was found to be a promising CH4 sensor.

To Japanese Contents To English Contents
35.

MwWƃKXZTo͂Ƃ̊֌W

{CMuCۉpF*CؑtF*

oϑoCH*

RELATIONSHIP BETWEEN THERMAL INDEX AND GAS SENSOR OUTPUT

Yoshinori NAKAMOTO, Takashi OYABU, Hidetaka NAMBO* and Haruhiko KIMURA*

Faculty of Economics, Kanazawa University of Economics
Ushi 10, Gosho-machi, Kanazawa, Ishikawa 920-8620, Japan
*Faculty of Engineering, Kanazawa University
2-40-20, Kodatsuno, Kanazawa, Ishikawa 920-8667, Japan

As human grow older, sensitivities become dull. Especially, the sensitivity for thermal index goes down. So, it is important to compensate or act for the sensitivity. By the way, the output of tin oxide gas sensor is influenced by temperature, humidity and atmospheric pressure. The comfortable index in a residential environment is related with these elements. Therefore, it is researched to derive the comfortable index based on the sensor output. In this report, it is clarified that high level of the comfortable index is equivalent to usual level of the temperature index and humidity index chiefly, and, low level of the comfortable index is equivalent to high level of humidity index. The sensor output of comfortable index is about 2.0V, and uncomfortable index is about 1.7V.

To Japanese Contents To English Contents
36.

_̏C\|[XVJ̒ƃZTޗւ̉p

AR@ցAX@EACAV*AT*A@*

HEOHdH茤*

PREPARATION OF MESOPOROUS SILICA MODIFIED WITH@SEMICONDUCTOR OXIDES AND ITS APPLICATION TO GAS SENSOR MATERIALS

Yasutake TERAOKA, Atsushi YAMAZAKI, Isamu MORIGUCHI, Shuichi KAGAWA, Nariyuki TOMONAGA*, Akinoro YASUTAKE* and Jun IZUMI*

Department of Applied Chemistry, Faculty of Engineering, Nagasaki University
Nagasaki 852-8521, Japan
*Nagasaki Research & Development Center, Mitsubishi Heavy Industries, Ltd.
Nagasaki, 851-0392, Japan

The coating of the inner wall of mesoporous silica with SnO2 and TiO2 has been investigated by a layer-by-layer coating technique to prepare "(semi)conductive mesoporous materials. Mosoporous silicas (MPS) with pore diameters between 23 and 36 and specific surface areas between 1200 and 1450 m2 g-1 were suspended and stirred in water for 1 h and dried at 110 overnight. The precursor materials, SnCl4 and Ti(OC4H9)4, were fixed on the wall through the reaction with hydroxyl groups by refluxing solutions of precursors suspended with MPS powder, followed by drying and calcination at 550 for 6 h. Characterization of products with respect to mesopore structure and UV-Vis absorption clearly indicates that the inner wall of MPS is coated with SnO2 and TiO2 progressively with increasing the number of the hydroxylation-fixation-calcination cycle (up to 3 times in this study). @

To Japanese Contents To English Contents
37.

ʉƒgCɂjICZT

u*A} _*2A Gm*3A쎛 *4A P*5A B*6

oϑw*AVRXXd@*2AHƑw*3Aw*4A ΐ쌧HƎ*5AtBKZ*6

Odor Sensing Characteristics in a Lavatory of General Home

Takashi OYABU*, Hiroshi KASAHARA*2 , Hidehito NANTO*3 , Takeshi ONODERA*4, Yoshiteru Doguchi*5 and Takeshi NAKAHARA*6

*Kanazawa University of Economics, Kanazawa 920-8620, Japan
*2New Cosmos Electric Co. LTD., Osaka 532-0036, Japan
*3Kanazawa Institute of Technology, Kanazawa 924-0838, Japan
*4Faculty of Engineering, Kanazawa University, Kanazawa 920-8667, Japan
*5Industrial Research Institute of Ishikawa Prefecture, Kanazawa, 920-0223, Japan
*6Figaro Engineering Inc., Osaka, 562-8505, Japan

Six odor sensors, which are of the metal-oxide semiconductor type, are installed in the lavatory of a general residence. Features of sensor-output patterns are derived by monitoring the odors. Frequency of lavatory-use and its intervals are detected and kinds of excretion are also identified. As for the results, two or three sensors react to urine and four or five sensors react to feces. The patterns, for example degree of fluctuation and inclination of output characteristic, differ with the subjects. This system can be applied to homes for the aged house to survey the residents' behaviors. The odor sensor system is also effective for monitoring the indoor environment without an infringement of privacy.

To Japanese Contents To English Contents
38.

ɂ銣dr쓮^bnZTpq[^

R{MK AXT

gN}AtBKZ

HEATERS FOR BATTERY|OPERATED CO SENSOR FROM PLATINUM THIN FILMS

Tokuyama Corp.
2023-1CEndoCFujisawa-shiCKanagawa252-0816, Japan
Figaro Engineering Inc.
1-5-11CSenbanishiCMino-shiCOsaka562-8505, Japan

We have developed heaters for battery-operated CO sensor from Platinum thin filmsD We used Platinum thin films to sensing electrodeCtooDThe gas sensing layer was printed on Platinum thin filmsDFrom various examinationCheater size was reduced and voltage was increased and ON period was shortDIn the case of a duty ratio of 4msec every 30 secCthe effective power consumption was about 0.06mWD This CO sensor can be operated by three ` type batteries for two yearsD

To Japanese Contents To English Contents
39.

In2O3nxEI𐫐fZT

́A

VRXXd@

HIGHLY SENSITIVE AND SELECTIVE H2 GAS SENSOR BASED ON SINTERED In2O3

Akira KATSUKI and Kiyoshi FUKUI

New Cosmos Electric Co., Ltd.
3-6-25, Mitsuya-Naka, Yodogawa-Ku, Osaka 532-0036, Japan

A highly sensitive and selective H2 sensor based on In2O3 was developed by use of a hot wire type semiconductor sensor commercially available. The powder of In2O3 was sintered in a bead(0.50 mm) covering over a platinum wire(0.02 mm) coil. Then, a SiO2 accumulated dense layer was formed near the surface of the porous bead by chemical vapor deposition(CVD) of hexamethyldisiloxane(HMDS). The sensitivity to H2 was about forty times as large as a current sensor based on SnO2. The sensor had also a very high selectivity to H2 (eg., the sensitivity to 5 ppm H2 was equal to that to 1000 ppm C2H5OH). Moreover, the sensor had a minor humidity dependence and a long term stability(about 900 days). Thus, indium oxide was a suitable material for the highly sensitive and selective H2 sensor.

To Japanese Contents To English Contents
40.

AuELa2O3/SnO2nAjAZT

c Kq

VRXXd@

NH3 GAS SENSOR BASED ON Au La2O3/SnO2 WITH PROTECTION COAT OF TiO2

Sachiko NISHIDA and Kiyoshi FUKUI

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

A NH3 gas sensor based on a hot wire type semiconductor sensor has been put into practical use. The NH3 gas sensor consisted of double sintered layers: an inner sensing layer of 0.02 at%Au, 4 mol%La2O3 supported on SnO2 (a sphere with the diameter of 0.45 mm)and an outer protection layer of TiO2(anatase, thickness of 0.1mm). The sensor temperature was ca. 300. The sensitivity to 25 ppm NH3 was ca. 40 mV. From a practical point of view, some important performances of the NH3 gas sensor were discussed in the present report: selectivity, response, influence of humidity, and long term stability.

To Japanese Contents To English Contents
41.

k3+yтx3+𕡍Y_̂bn2ZT̊JƎp

ԓc^qAvAu*A@O*

GtACGXEH*

DEVELOPMENT OF CO2 GAS SENSOR USING La3+ AND Y3+ DOPED SnO2 SEMICONDUCTOR

Mariko HANADA, Kazuo ONAGA, Masashi NISHIGUCHI* and Toru ONOUCHI*

FiS Inc.
3-36-3 Kitazono, Itami-shi, Hyogo 664-0891, Japan
*Matsushita Seiko Co., Ltd.
4017 Takagi-cho, Kasugai, Aichi 486-8522, Japan

To develop an inexpensive and compact CO2 gas sensing system for indoor air quality control, we have developed a CO2 gas sensor using SnO2 doped with La3+ and Y3+. The specific properties of the sensor are, 1) Yttrium addition prevented La from aggregation on the SnO2 surface under high humidity, 2) Filter made of silica gel and Pt effectively reduced the sensitivity to ethyl alcohol and humidity, 3) A pinhole disk placed between the filter and the sensor element removed the moisture effect due to the use of the silica gel filter. This CO2 sensor was proved to have sufficient performance in practical use.

To Japanese Contents To English Contents
42.

_CO2ZT̍xyэx̌

cOjAu*A@O*

GtACGXEH*

IMPROVEMENT OF SENSITIVITY AND ACCURACY OF SnO2 SENSOR FOR CO2 DETECTION

Hiroshi KODA, Masashi NISHIGUCHI* and Toru ONOUCHI*

FiS Inc.
3-36-3 Kitazono, Itami-shi, Hyogo 664-0891, Japan
*Matsushita Seiko Co., Ltd.
4017 Takagi-cho, Kasugai, Aichi 486-8522, Japan

We have newly developed two types of CO2 gas sensors to improve the characteristics of the CO2 gas sensor which has been marketed domestically since 1997. One is a small bead type gas sensor doped with La,Y and Pd and can detect CO2 and H2 with a single element. The other is a plate type SnO2 sensor composed of a compensation element and a detection element, and decreases the noise gas influence on the remaining CO2 sensitivity. The performance of these two types of CO2 sensors was satisfactory in a practical use.

To Japanese Contents To English Contents
0.

@

@

@

@

@

@, Japan

@

To Japanese Contents To English Contents

To On-line Chemical Sensors Index Page (Japanese)
To On-line Chemical Sensors Index Page (English)