The disposable tip in a positive displacement micropipette is a microsyringe composed of a capillary and a piston (movable inner part) which directly displaces the liquid. In these micropipettes, the piston comes in direct contact of the sample. Instead, a disposable pipette tip is used to draw the liquid into and dispense from the pipette. The internal mechanism of the pipette does not come in direct contact of the sample/liquid. It consists of a piston which aspirates and dispenses liquid samples as the air pocket moves up and down, respectively. This type of micropipette works on the air displacement principle. Micropipettes can be classified depending upon:

While the single-channel micropipettes are used in labs that perform research related to molecular biology, microbiology, immunology, cell culture, analytical chemistry, biochemistry and genetics, the multichannel micropipettes are recommended for ELISA (diagnostic test), molecular screening, kinetic studies and DNA amplification. Micropipettes are available in single-channel and multi-channel variants. A micropipette is a common yet an essential laboratory instrument used to accurately and precisely transfer volumes of liquid in the microliter range.

Pipette 23.6.13 download