Which type of pipette is used to deliver a fixed volume?

A volumetric or transfer pipette is designed to deliver a specific, fixed volume of liquid with high accuracy and precision. This type of pipette has a bulb in the middle and a tapered end, ensuring that it can accurately measure and dispense the designated volume when filled to the marked line.

The volumetric pipette is particularly beneficial in analytical chemistry and other scientific applications where precise measurements are critical. It's generally calibrated to deliver only one specific volume, which makes it ideal for experiments requiring exact liquid measurements.

In contrast, measuring pipettes can hold varying amounts of liquid and are used for measuring different volumes based on the user’s needs. Gravimetric pipettes are less common and often used in specific scenarios that involve weighing substances, while disposable pipettes are typically used for transferring small amounts of liquid without precision. These alternatives do not deliver a fixed amount in the same precise manner as volumetric pipettes, which highlights why the latter is the preferred choice for delivering a fixed volume of liquid.