Graduated pipette

From Sciencemadness Wiki
Jump to: navigation, search

Graduated pipettes are pipettes with various volumes marked along the tube. They are used to measure and transfer an accurate volume of liquid from one container to another, and they're more accurate than graduated cylinders.

General

Graduated pipettes consist of a glass tube, with one end getting narrow, while the other end has a narrow neck. There are graduation marks on the pipette. Typical volumes for graduated pipettes are 1, 2, 5, 10, 20 and 25 ml. Larger volume pipettes aren't used, burettes are employed instead.

Types

Mohr pipette

The Mohr pipette does not have its first (lowest) graduation mark until the end of the tip. Error can occur because of improper use by the person using the pipette or if there is a brake or crack in the pipette. This type is designed for use as a drain-out pipette.

Serological pipette

The Serological pipette has the graduation marks reach to the end of the tip. Any remaining solution that stays in the pipette instead of being transferred can affect an experiment by allowing an incorrect amount of solution to be transferred. This type is designed for use as a blow-out pipette.

Availability

Graduated pipettes are sold by lab suppliers.

See also

References

Relevant Sciencemadness threads