Centrifugate

Centrifugate is a term used to refer to the product of centrifugation or to the act of subjecting a sample to centrifugal force. As a process, centrifugation separates components by density; as a noun, a centrifugate can denote the material obtained after spinning, typically a pellet at the bottom and a clarified supernatant above, depending on rotor type and conditions.

Centrifugation relies on rotational acceleration to generate a relative centrifugal force measured in g. The main variables are speed (rpm), time, rotor geometry, and temperature. Different rotor configurations influence sedimentation patterns: fixed-angle rotors keep samples at a fixed angle, while swinging-bucket rotors allow fluids to move to a horizontal orientation during spin.

Techniques include differential centrifugation, which separates components based on size and density, and density gradient centrifugation, which uses a density gradient to resolve components by buoyant density. Ultracentrifugation employs very high speeds to separate small particles such as viruses or macromolecules.

Applications span biology, medicine, and biotechnology. Centrifugation is used to isolate cells and subcellular organelles, purify proteins and nucleic acids, clarify biological fluids, and prepare plasma components or microbial cultures. In clinical laboratories, it enables plasma or serum separation, platelet-rich plasma preparation, and removal of unwanted particulates from samples.

In practice, the term centrifugate appears more often in older or broader literature; modern protocols frequently refer to the centrifuged sample, the pellet, or the supernatant rather than to centrifugate. The concept remains a core technique in laboratory separation and purification.