Method for the quality-assessed metering of a metering fluid, and pipetting device designed to carry out the method

A method for quality-assessed metering of a metering fluid by means of a pipetting device, where the pipetting device comprises:

• a pipetting duct filled at least in part with a working gas,
• a pipetting piston accommodated movably in the pipetting duct in order to modify a pressure of the working gas in the pipetting duct through a piston movement,
• a pipetting aperture traversable by metering fluid in order to alter the quantity of fluid received in the pipetting duct,
• a piston drive in order to drive the pipetting piston to a movement along the pipetting duct,
• a pressure sensor in order to capture the pressure of the working gas in the pipetting duct,
• a control device for storage and processing of data and for actuating the piston drive,
• where the method comprises the following steps:
• performing a metering process by moving the pipetting piston and thereby modifying the pressure of the working gas in the pipetting duct and thereby altering the quantity of metering fluid received in the pipetting duct,
• capturing a temporal course of the pressure of the working gas in the pipetting duct during the metering process,
• comparing a course of the working gas pressure on the basis of the captured temporal course of the working gas pressure with a specified pressure target values range, and
• outputting a quality assessment of the metering process as a function of the result of the comparison step,
• where the method further comprises the following further steps, where the control device performs the further steps while the pipetting duct is filled essentially solely with working gas as fluid:
• performing a correction pressure determining process by moving the pipetting piston and thereby modifying the pressure of the working gas in the pipetting duct and thereby aspirating working gas into the pipetting duct and/or dispensing working gas out of the pipetting duct, and
• capturing a pressure of the working gas in the pipetting duct during the correction pressure determining process as a correction pressure,
• where the control device performs the following further step before the comparison step:
• correcting the temporal course of the working gas pressure captured during the metering process on the basis of the correction pressure of the working gas captured during the correction pressure determining process, such that the comparison step is performed with the corrected temporal course of the working gas pressure.