Abstract: A pipette assembly having a pipetting unit having a pipette housing with a cylinder chamber and a pipetting opening, as well as a piston moveably mounted in a cylinder chamber, and a drive unit that acts on the piston, wherein the drive unit has a mode switch that can be shifted from a manual mode position into a stepwise mode position such that, when the mode switch is in the manual mode position, the actuation element can be actuated in a manual actuation mode, such that a pipetting volume can be output that is proportional to the movement of the actuation element, and when the mode switch is in the stepwise mode position, the actuation element can be actuated in a stepwise actuation mode in such a way that a determined pipetting volume is output for each actuation of the actuation element.

Abstract: A method is provided for calibrating impedance-spectroscopic biomass sensors that are embodied to detect information regarding the quantity and/or size of living cells in a biomass by means of an electric field having a periodically changing field direction A calibration suspension encompasses an electrically conductive viscously flowable or viscoelastic carrier substance and electrically conductive solid particles and/or solid semiconductor particles received therein. An electric field is generated having a periodically changing field direction, which acts on the calibration suspension. At least one permittivity value is detected, respectively representing a permittivity of the calibration suspension, in a context of at least two electric fields having different field direction change frequencies. A difference value is ascertained that represents a difference between the detected permittivity values. The difference value is compared with a reference value associated with the calibration suspension.

Abstract: A method is provided for calibrating impedance-spectroscopic biomass sensors that are embodied to detect information regarding the quantity and/or size of living cells in a biomass by means of an electric field having a periodically changing field direction A calibration suspension encompasses an electrically conductive viscously flowable or viscoelastic carrier substance and electrically conductive solid particles and/or solid semiconductor particles received therein. An electric field is generated having a periodically changing field direction, which acts on the calibration suspension. At least one permittivity value is detected, respectively representing a permittivity of the calibration suspension, in a context of at least two electric fields having different field direction change frequencies. A difference value is ascertained that represents a difference between the detected permittivity values. The difference value is compared with a reference value associated with the calibration suspension.