Dead volume reduction and method therefor

A method for minimizing the dead volume (Vd) in a vial (10) presenting a liquid (L) for aspiration utilizing a hysteresis determination method, the method comprising:

• conductively detecting a conductive surface (30) by means of pipetting arm (20) presenting a pipetting tip (21);
• storing the position of the pipetting arm (20) when conductively detecting the conductive surface (30) as first position (P1z);
• moving the pipetting arm (20) towards the conductive surface (30) and along the z-axis of the pipetting arm (20) until the pipetting arm (20) applies a predetermined force and therefore comes to a stop;
• storing the position when the pipetting arm (20) comes to a stop as second position (P2z);
• calculating the hysteresis (Hz) by determining the height difference between the first position (P1z) and the second position (P2z).

A computer-implemented method for controlling an at least one pipetting arm (20) of a liquid handling system (1) for minimizing the dead volume (Vd) in a vial (10) presenting a liquid (L) for aspiration, the automated liquid handling system comprising:

• at least one pipetting arm (20) connectable to a pipetting tip (21) and operatively connected to a pressure source for aspirating and dispensing liquids;
• a workbench (5) for supporting vials (10) for presenting a liquid (L);
• means for liquid level detection;
• an operational unit (40) configured to perform a method for minimizing the dead volume (Vd) in the vial (10) presenting the liquid (L) for aspiration,
• the method comprising:
• determining whether the liquid volume (Vi) indicated to be available in the vial (10) is sufficient for a further aspiration step;
• if not, moving downward in direction towards the bottom of the vial by means of the pipetting arm (20) presenting a pipetting tip (21) and along the z-axis of the pipetting arm (20) until the pipetting arm (20) comes to a stop in a first stop position (S1z);
• storing the first stop position (S1z) of the pipetting arm (20) or correcting the first stop position (S1z) by a predetermined safety measure (Ds) and storing this first safety corrected stop position (S1SCz) of the pipetting arm (20);
• and further
• calculating the actual available liquid volume (Va) based on the liquid level known from determining whether the liquid volume (Vi) indicated to be available in the vial (10) is sufficient for a further aspiration step and the first stop position (S1z) or calculating the actual safety corrected available liquid volume (VaSC) based on the liquid level determining whether the liquid volume (Vi) indicated to be available in the vial (10) is sufficient for a further aspiration step and the first safety corrected stop position (S1SCz);
• and/or
• detecting the liquid level (LL) of the liquid (L) provided in the vial (10) and calculating the actual available liquid volume (Va) based on the detected liquid level (LL) and the first stop position (S1z) or calculating the actual safety corrected available liquid volume (VaSC) based on the detected liquid level (LL) and the first safety corrected stop position (S1SCz),
• the method further comprising:
• conductively detecting a non-anodized aluminum surface by means of the pipetting arm (20) presenting the pipetting tip (21);
• moving the pipetting arm (20) towards the non-anodized aluminum surface and along the z-axis of the pipetting arm (20) until the pipetting arm (20) applies a predetermined force and therefore comes to a stop.