2018-10-142018-10-142005http://hdl.handle.net/20.500.12091/482Mechanical micropipettes (Fig. 2.22) can only be recommended where a reliable supply of new disposable tips is readily available. They are used for the delivery and/or dilution of biological samples in the volume range 5-1000 |al. They are usually of air displacement (indirect) or direct displacement design. To avoid contamination between consecutive samples, most pipettes have a disposable tip that is discarded after each delivery. This greatly increases the cost per test. The practice of washing and reusing disposable tips is not recommended, as any cleaning procedures will change the "wettability" of the plastic. In addition, drying at only slightly elevated temperatures may distort the tip, and prevent a good pneumatic seal with the pipette body.en-USPipettesArticle