When preparing the master mix, at least 10 % extra volume should be added (e.g. if 10 preparations are required, calculate on the basis of 11), so that even the last vessel filled properly. In this way, (slight) pipetting inaccuracies, and the effect of sample loss when dosing detergent-containing solutions can be compensated. Detergents are contained in enzyme solutions such as polymerases and master mixes, causing foam formation and residues on the inner surface of normal pipette tips.
Depending on the application and the type of liquid to be dispensed, the correct pipetting technique (1) should be chosen and the appropriate equipment selected (2). For solutions containing detergents, a direct displacement system or the so-called "low retention" pipette tips as an alternative for air-cushion pipettes are recommended. The effect of epT.I.P.S.® LoRetention is based on a particularly hydrophobic surface. Liquids containing detergents do not leave a residue film on the inside and outside, so that the loss of solution can be minimized (Figure 1).