A method for registering the filling potential of a waste container (1) of a microplate washing device (2), the microplate washing device (2) at least comprising:
- a washing needle (5) for aspirating liquids (10);
- said waste container (1), being closable substantially airtight, for catching aspirated liquids (10);
- a pump (3) for generating a partial vacuum in the waste container (1), wherein the pump (3) and the washing needle (5) are each connected via at least one line (6,6′) to the waste container (1);
- and
- a pressure sensor (4), which is operationally linked to the waste container (1) for determining an air pressure therein, and a sensor controller (14);
- wherein the microplate washing device (2) further comprises a valve (7) for blocking the line (6) between the washing needle (5) and the waste container (1);
- wherein the method comprises the following steps:
- a) defining a threshold time (22) for an arbitrarily defined safety residual volume in a waste container (1) measured beforehand in a separate calibration measurement, which threshold time (22) is the time for a partial vacuum dissipation within a predetermined partial vacuum test range for the safety residual volume of a waste container (1)
- (b) closing the valve (7) between the washing needle (5) and the waste container (1) and generating a partial vacuum in the waste container (1) at least to a lower limiting pressure (25) of the predetermined partial vacuum test range;
- c) blocking the pump-side line (6′) to the waste container (1);
- d) opening the valve (7) between the washing needle (5) and the waste container (1) and triggering a partial vacuum dissipation in the waste container (1);
- e) measuring the pressure in the waste container (1) and measuring a test time (21) for the partial vacuum dissipation between the lower limiting pressure (25) to an upper limiting pressure (26) of the partial vacuum test range, wherein the upper limiting pressure (26) is less than the ambient pressure;
- f) comparing the measured test time (21) to the threshold time (22) established before the measurement, and
- g) deciding that:
- (g1) the waste container (1) is not fillable, if the test time (21) falls below the threshold time (22), or
- (g2) the waste container (1) is fillable, if the test time (21) is equal to the threshold time (22) or
- (g3) the waste container (1) is fillable, if the test time (21) exceeds the threshold time (22);
- and wherein, prior to the measurement of step e):
- i) a first tolerance time (23) is established, the first tolerance time (23) being the time of a partial vacuum dissipation in the partial vacuum test range for a residual volume of a waste container (1) which is larger by a first volume than the residual volume for the safety residual volume defined in step a) for the threshold time (22);
- and
- ii) a second tolerance time (24) is determined, the second tolerance time (24) being the time of a partial vacuum dissipation in the partial vacuum test range for a residual volume of a waste container (1) which is greater by a second volume than the sum of the safety residual volume defined in step a) for the threshold time (22) with the first residual volume for the first tolerance time (23).