Pipette - Piston-driven Air Displacement Pipettes

Piston-driven Air Displacement Pipettes

These pipettes operate by piston-driven air displacement. A vacuum is generated by the vertical travel of a metal or ceramic piston within an airtight sleeve. As the piston moves upward, driven by the depression of the plunger, a vacuum is created in the space left vacant by the piston. The liquid around the tip moves into this vacuum (along with the air in the tip) and can then be transported and released as necessary. These pipettes are capable of being very precise and accurate. However, since they rely on air displacement, they are subject to inaccuracies caused by the changing environment, particularly temperature and user technique. For these reasons this equipment must be carefully maintained and calibrated, and users must be trained to exercise correct and consistent technique.

The micropipette was invented and patented in 1960 by Dr. Hanns Schmitz of Marburg, Germany. Afterwards, the co-founder of the biotechnology company Eppendorf, Dr. Heinrich Netheler, inherited the rights and initiated the global and general use of micropipettes in labs. In 1972, the adjustable micropipette was invented at the University of Wisconsin-Madison by several people, primarily Warren Gilson and Henry Lardy.

Several different type of air displacement pipettes exist:

• adjustable or fixed
• volume handled
• Single-channel, multi-channel or repeater
• conical tips or cylindrical tips
• standard or locking
• manual or electronic
• manufacturer