centrífugs

A centrifuge is a laboratory device that separates components of a mixture based on their density by spinning them at high speeds. The sample is placed in a tube that is balanced in a rotor; as the rotor turns, centrifugal force pushes heavier particles outward while lighter substances stay closer to the axis of rotation. The result is a clear separation of layers that can be easily collected.

The principle behind centrifugation is straightforward: a solid body moving in a circular path experiences a centrifugal acceleration equal to the product of its angular velocity squared and the radius of its path. This force works in tandem with gravity, but the extreme speeds give much greater effective g-forces, allowing separation of substances with very small density differences, such as cells from plasma or DNA fragments from cellular debris.

Centrifuges come in a variety of sizes and designs. Small benchtop centrifuges are suited for routine biochemical assays, while ultracentrifuges can reach velocities up to 200,000 rpm, necessary for purifying viruses, ribosomes or subcellular organelles. Swinging-bucket rotors allow samples to pivot so that the centrifugal force acts parallel to the tube axis, which is important for density gradient centrifugation.

Historical development began in the mid‑19th century with Robert Bunsen’s original centrifuge used for separating blood cells. Since then, improvements in motor technology, rotor materials, and temperature control have broadened their use beyond biology to fields such as geophysics, material science, and food technology.

Safety considerations include balancing tubes, using rotor caps, and guarding against rotor failure, which can produce hazardous high‑speed fragments. Proper training and adherence to manufacturer guidelines are essential for safe operation.