Patent ID: 8726746
Filing Date: 2014-05-20
Classification: B01L,G01F,G01N

Abstract:
1. A method for checking the state of a pipette, the pipette comprising a suction tube and a pipette tip, the method comprising: coupling an ultrasonic signal into the wall of the suction tube, wherein said ultrasonic signal is generated by a piezo actuator disposed between said wall of said suction tube and an additional mass, said piezo actuator mounted on said wall of said suction tube, said piezo actuator in contact with said additional mass on a side facing away from said suction tube; measuring the frequency-dependent damping of the ultrasonic signal in the wall of the suction tube in a predefined frequency range comprising a plurality of frequencies as a function of the frequency; comparing the measured frequency-dependent damping in the predefined frequency range with at least one reference measurement of the frequency-dependent damping or a calibration curve, based on the reference measurements, in order to form a comparison and determine whether the pipette contains fluid or has made contact with the fluid, wherein said additional mass is configured to increase the amount of change in the frequency-dependent damping of the ultrasonic signal in the wall of the suction tube when the pipette contains fluid or has made contact with the fluid.