Which micropipettor uses suction to draw liquid into the tip?

• A. Air displacement micropipettor
• B. Positive displacement micropipettor
• C. Dispenser/Dilutor Pipet
• D. Manual pipette

Answer: (A)

The mechanism uses suction created in an air-filled chamber to pull liquid into the tip. In an air-displacement micropipettor, pressing and then releasing the plunger lowers the pressure inside the air pocket above the liquid, so the liquid is drawn up into the disposable tip until the set volume is achieved. This is the conventional way most micropipettes aspirate samples.

A positive-displacement micropipettor works differently: the liquid is drawn into a bore that directly contacts a piston, without relying on an air cushion, so it doesn’t use the same suction through a tip. A dispenser/dilutor is meant for delivering liquids in larger-scale tasks rather than precise aspiration into a tip, and a manual pipette is a broad term that doesn’t specify the suction-based air cushion mechanism.