Patent ID: 8646317

Claim:
A sensing device in which a piezoelectric sensor including a piezoelectric resonator is mounted and which senses a substance to be sensed in a sample solution based on an oscillation frequency obtained when the sample solution flows from a supply channel to one surface side of the piezoelectric resonator, the sensing device comprising: a reference liquid supply part provided to supply a reference liquid to the supply channel and capable of varying a supply flow rate of the reference liquid; a sample solution storage channel which is interposed between the reference liquid supply part and the supply channel to temporarily store the sample solution, and from which the sample solution is sent to the supply channel by being pushed by the reference liquid supplied from the reference liquid supply part; a channel switching part switching a channel between a reference liquid supply mode in which the reference liquid supply part is connected to the supply channel not via the sample solution storage channel and a sample solution supply mode in which the reference liquid supply part is connected to the supply channel via the sample solution storage channel; a control part determining whether or not the oscillation frequency is stabilized while the reference liquid is supplied to the piezoelectric resonator from the reference liquid supply part, and when determining that the oscillation frequency is stabilized, switches the channel switching part to the sample solution supply mode in order to cause the supply of the sample solution in the storage channel to the piezoelectric resonator; a flow rate setting part via which the supply flow rate of the reference liquid supply part is set; and a computing part which finds an instant at which the sample solution reaches the piezoelectric resonator and an instant at which the sample solution finishes passing through the piezoelectric resonator, based on the supply flow rate of the reference liquid set via the flow rate setting part, a volume of the sample solution storage channel, a volume of the supply channel, and an instant at which the channel switching part is switched to the sample solution supply mode, and finds an oscillation frequency during a period from the switching instant to an instant before the sample solution reaches the piezoelectric resonator and an oscillation frequency after the sample solution passes through the piezoelectric resonator to obtain a difference between the oscillation frequencies.