What is the function of a blow-out feature on a pipette?

The blow-out feature on a pipette is designed to ensure that the last drop of liquid is expelled from the pipette tip. This is particularly important in quantitative analyses where the volume delivered must be precise. When a pipette has a blow-out feature, it typically involves a slightly larger tip or a specific design that allows for a complete release of liquid. After the initial aspiration and dispensing process, pressing the blow-out feature forces out any residual liquid remaining in the tip, ensuring accurate measurement of the intended volume. This is especially critical for experiments and procedures where every drop counts, such as in reagent preparation or when transferring samples in laboratory settings. Thus, this feature enhances the accuracy of volume transfer in a laboratory environment.