Aspiration of a pipette arrangement is initiated. A sensor arrangement senses a least one prevailing first parameter that is dependent from the effect in the pipette arrangement during initiating and upholding the suctioning action. This at least one parameter is analyzed in an analyzing stage. From a result of this analysis and in a determining stage at least one test criterium TC for at least one further parameter as sensed by the sensor arrangement is determined. In a checking stage there is checked whether this further parameter fulfills the at least one test criterium.