The filter tip is a consumable to prevent cross contamination.
Generally speaking, there is no problem with forward pipetting when using filter tips. However, in some special situations, some filter tips may not be suitable. The design of some filter tips does not fully consider the possibilities of various applications, and does not leave enough space in the tips. So when you need to use reverse pipetting to suck in extra volume of liquid, or when the pipetting liquid is rich in protein and prone to foam, “tragedy” may happen at any time. You may find that after the liquid is absorbed, the closeness of the liquid and the filter element is released.
In this way, the pollution may still spread. In order to control the pollution risk caused by the “close contact between the liquid and the filter element”, some brands have installed double filter elements in the suction head or designed a closing mechanism (when the liquid contacts the filter element, the filter element is automatically closed so that the liquid cannot be discharged). Still cannot change the fact that precious samples are lost. The choice at this time is to buy a tip with enough space in the tip to ensure that even in special applications, the possibility of liquid contact with the filter element can still be prevented. Please remember its name is “safety space”