By Tanya Knaide and Keith J. Albert, Artel
All pipette tips are not created equal, nor are all assays. Failure to use proper tips for a given type of pipette can lead to an inadequate seal between the pipette and tip, causing inaccurate volume transfers due to leakage and sample loss. The need for the best performing tip is likely proportional to the importance of having both accuracy and precision in volume delivery for specific assay steps. For instance, dispensing relatively large volumes of phosphate buffer into a plate might not be as critical as dispensing 1 μL of compound for drug candidate screening or 15 μL of mastermix addition in PCR assays.
Often, the driver for selecting, or switching, the type of tip is based on cost. Unfortunately, decisions to use new or different tip types are not usually based on tip performance, quality or reliability because these factors are not routinely characterized. This document gives examples of how testing volume transfer performance can give good indicators of tip performance and reliability. When tip reliability is in question, assay results, in turn, could be in question as well.