Development and evaluation of a micropipette tip washing system

A tip washing system has been developed for use with disposable polypropylene micropipette tips of different sizes. The primary hardware components of the system are constructed from polyvinyl chloride (PVC) and Plexiglas. The system relies on a low concentration of detergent, gravity or aspirator-assisted feed and flush of minimal volumes of distilled/deionized water, and air or oven drying of the tips. Comparative analyses of new versus washed tips in FAO/IAEA radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA) protocols indicated that disposable polypropylene micropipette tips of various sizes (e.g. 5-300 and 50-1000 microl) can be washed and reused at least ten times without introducing detectable variability into the results of either assay, if the tips are properly washed and dried using this system. Recovery cost of the system can be achieved after approximately eight reuses of 1000 tips, excluding technician time.