Pipette bulbs (also known as or pipet bulbs, pipetting balls or pipettor bulbs) are manual pipetting devices used to fill serological pipettes, volumetric pipettes or transfer pipettes.

What sort of pipette bulbs are available?

• Simple suction rubber bulbs or teats for use with small Pasteur pipettes or transfer pipettes that operate on a simple ‘suck-in and blow-out’ principle
• Larger, heavier-duty simple suction bulbs with thicker walls for larger pipettes
• Safety pipette bulbs for use with serological or volumetric pipettes that avoid the traditional practice of using mouth suction. Safety pipette bulbs are typically made of silicone, natural or synthetic rubber. They have a tight-fitting nozzle into which the top end of the pipette is inserted, and also three ‘pinch-and-release’ ball-valved openings operated in sequence to control (1) the expulsion of air from the bulb; (2) the suction of liquid into the pipette and (3) the discharge and dispense of the liquid. So called ‘flip’ pipette fillers have just two operating valves to facilitate one-handed usage. Most safety bulbs are of a universal ‘one-size-fits-all’ design, and generally accommodate a range of pipette capacities from 1mL up to 100mL or more.

What are pipette bulbs used for in the lab?

• Pipetting of hazardous reagents and chemicals
• Routine and repetitive dispense of sample aliquots
• Controlled drop-by-drop transfer of reagents or histological stains

Bulbs are generally washable for repeated use, but care must be taken to avoid ingress of aggressive fluid into the interior of the bulb which could contaminate, damage or malfunction.