Pipettes are portable devices typically smaller than burettes.
Although laboratory analysts use burette and pipette tools to make precise measurements of fluids, they are used for different purposes. A burette is normally a fixed piece of equipment, while a pipette is mobile. Pipettes can collect and deliver fluids, while a burette only delivers fluids. Typically, an analyst fills a burette from the top down, while a pipette fills from the bottom up. Both instruments have graduations to measure precise volumes of liquid, but pipettes tend to be more suitable for smaller volumes than burettes.
Pipettes and micropipettes are chemical droppers used to measure and dispense exact amounts of liquids.
One of the main differences between a burette and a pipettor is that the pipettor is portable and the burette is normally fixed to a stand on the laboratory bench. Both are long, thin hollow tubes designed to hold liquids. A burette is often made of glass, while a pipette often comes in both plastic and glass versions.
As hollow tubes are primarily measuring devices, both the burette and pipette have markings along the side to signal when a certain volume of liquid is present within the tube. Because lab analysts hold pipettes in their hands, pipettes tend to have smaller volume capacities than a burette, which can be larger because it remains stationary on the lab bench. The way a burette is filled with liquid is another difference between a burette and a pipette.
Pipettes can be used to collect and administer fluids.
Burettes have an open top for the tube and a small exit point at the other end of the tube, which is closed with a stopcock. Therefore, an analyst pours the liquid into the burette at the top, until the required volume marker is reached. A pipette, on the other hand, does not have a tap locking mechanism, but is instead an open, hollow tube with a tapered end.
Pipettes require a suction device at the top end, which changes the pressure inside the tube to draw liquid through the tapered end of a liquid container. As long as the suction pressure remains on the pipette, the liquid will remain inside the tube. When the suction is removed, the liquid flows out, since the lower end of the tube does not have a mechanical locking system like the burette.
A burette and a pipette are generally used for different purposes in laboratory procedures. The burette delivers precise volumes of liquid to another container, as in a titration. When an analyst tests two substances, he analyzes how much of one substance is needed to make a visually recognizable change in the other substance.
The changes in appearance relative to the volume of the liquid can be used to calculate the concentrations of certain components in the sampled substance. Pipettes can also be used in titrations, but since they contain less liquid and may require refills, the burette is more time efficient. On the other hand, since burettes are difficult to use, pipettes are the preferred way of measuring liquids and dispensing them into other containers.