Often used in biological laboratories as well as in cosmetics and food production, a serological pipette typically helps transfer small amounts of liquid. It is generally a relatively narrow plastic tube with markings for volume measurements, which are usually labeled in milliliters. Liquid solutions can be transferred from one place to a different container, and a small manual pump is often used to get all of the fluid at the tip out of the device. Pipettes in which some fluid remains and is typically part of the total volume are called to contain, while to deliver variants have extra fluid at the tip that is usually discarded. Most serological pipettes are labeled according to what type they are.
Many pipettes are disposable and can be purchased as one component or a package of up to 50 or more units. The volume markings are usually derived during a temperature calibration, which can allow for accuracy in a 68° to 77°F (20° to 25°C) range. Inside the serological pipette, liquid typically forms a pattern called a meniscus in response to the interior shape. Researchers can get the correct reading by holding the device straight up and lining up the bottom of the meniscus with the nearest measurement line. Measurements can be done by emptying the entire pipette, or by draining a specific amount of fluid by noting the desired volume marking to change the level to.
Small, handheld pumps are often used to drain a serological pipette. These can feature a button to activate, a thumb roller, or a variety of other designs. Some pumps have a filter that may need to be changed periodically. Depending on the application, some pipettes are designed to be more accurate. Many are manufactured as one single part, often molded out of a plastic composite. They can also be designed without welds so there are no pieces inside the pipette that can trap liquid.
A serological pipette can have a plug, sometimes made of cotton, which helps to prevent researchers from overfilling it. In packages of many pipettes, the plug can be color-coded along with other labels to indicate specific sizes and types in the box. Serological pipettes and related scientific equipment are often used in laboratories where biological and chemical compounds are used. They are usually non-toxic, and are sometimes used in educational settings. Hospitals and even industrial facilities can make use of serological pipette products as part of their inventory.