Analytical device and method utilizing a piezoelectric crystal biosensor
 A bio-sensor is mounted in a container and comprised of a receptor for selectively reacting with a specific biochemical substance in a sample liquid held in the container to bind thereon the specific biochemical substance and a resonator integrated with the receptor for detecting the amount of the specific biochemical substance bound to the receptor in terms of a resonant frequency shift of the resonator. A measuring circuit is connected to the sensor for measuring the resonant frequency shift of the resonator within the container; a switching valve operates during the reaction of the receptor with the specific biochemical substance to charge a sample liquid into the container to contact the sample liquid with the receptor to thereby effect the reaction and operates during the measurement of the resonant frequency shift to replace the sample liquid by a buffer liquid in the container to immerse the sensor in the buffer liquid to thereby prevent a fluctuation of the resonant frequency shift. 
Seiko Instruments & Electronics Ltd.
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G01N G01N G01N Y10S Y10S Y10S
inventional additional inventional additional additional additional
Isao Hiroshi
Karube Muramatsu