Positive Displacement Pipette, is used for applications like PCR and other DNA
amplification techniques. The micro-syringe tips used in positive displacement pipettes
are disposable. This helps to avoid sample-to-sample cross-contamination (also known
as sample carry-over), and contamination due to the aerosol effect.
meant for general use with aqueous solutions.
In air displacement pipettes, a certain volume of air remains between the piston
and the liquid.