Centrifugálszivattyúknál

Centrifugálás, also known as centrifugation in English, is a laboratory technique that uses centrifugal force to separate components of a mixture according to density. A sample is placed in a rotor and spun at high speed, causing heavier or denser particles to move outward and settle at the bottom or along a gradient, depending on the method.

The technique has roots in the late 19th and early 20th centuries, with significant advances by Theodor Svedberg, whose work on ultracentrifugation led to the development of sedimentation theory and the use of the Svedberg unit to describe particle size and density. Since then, centrifugation has become a routine tool in chemistry, biology, medicine, and environmental science.

Key principles include the relative centrifugal force (RCF), which depends on rotor radius and rotational speed. RCF is calculated as approximately 1.118 x 10^-5 x r (in centimeters) x (rpm)^2. The choice of rotor type (fixed-angle or swing-bucket), tube format, and temperature control influence separation efficiency and sample integrity. Different protocols aim for pelleting, banding, or equilibrium in a density gradient.

Common techniques include differential centrifugation, which separates by size and density through sequential spins, and density gradient centrifugation, which uses media such as sucrose or cesium chloride to separate components by buoyant density. Applications span purification of nucleic acids, proteins, organelles, lipoproteins, and viruses, as well as clinical plasma separation and wastewater treatment.

Safety and quality considerations are important: proper rotor balancing, adherence to maximum speeds, appropriate tubes, and careful handling to prevent sample damage and rotor failure.