Patent ID: 8601859
Filing Date: 2013-12-10
Classification: G01N

Abstract:
1. A sensing device that uses a piezoelectric sensor structured by forming an absorption layer on an electrode provided on a piezoelectric piece and senses, by making the adsorption layer adsorb a substance to be sensed in a sample solution, the substance to be sensed based on a variation in natural frequency of the piezoelectric piece, the sensing device comprising: an oscillator circuit for oscillating the piezoelectric piece; a frequency measuring part measuring an oscillation frequency of said oscillator circuit; a data obtaining part sampling a frequency measured in said frequency measuring part at a previously set time interval to obtain time-series data of the frequency; a storage part storing a previously set measuring time for measuring a variation in frequency when the sample solution is supplied to the piezoelectric sensor; and an output part sequentially calculating a frequency stability of a group of sampling spans each starting from each sampling timing of the frequency and having a length corresponding to the measuring time, for each of the sampling spans, when a reference solution which does not contain a substance to be absorbed in the absorption layer is supplied to the piezoelectric sensor and outputting a supply enable signal for the sample solution when the calculated frequency stability becomes equal to or less than a tolerance value corresponding to a measurement sensitivity.