Which type of centrifuge is used when rapid centrifugation of solutions containing small particles is needed?

• A. Horizontal-head centrifuge
• B. Swinging-bucket centrifuge
• C. Fixed-angle centrifuge
• D. Cytocentrifuge

Answer: (C)

A fixed-angle centrifuge is particularly effective for rapid centrifugation of solutions containing small particles. This type of centrifuge holds the tubes at a constant angle relative to the axis of rotation, allowing substances to quickly settle towards the bottom of the tube due to the centrifugal force created during spinning.

The design facilitates efficient separation because the particles experience maximum gravitational force in a shorter amount of time compared to other types of centrifuges. This results in a rapid accumulation of sediment at the bottom, which is crucial when dealing with samples that may contain small particles, such as cellular components, particulates in serum, or small latex beads.

In contrast, a horizontal-head centrifuge takes longer to achieve separation as it allows for a more gradual settling process due to its bucket design, while a swinging-bucket centrifuge moves the buckets outward during rotation, which can lead to longer run times for particle separation. A cytocentrifuge is specialized for cell samples and prepares slides for microscopic examination, especially for cytology. Thus, while all these centrifuge types have their unique applications, the fixed-angle centrifuge is especially suited for situations requiring rapid and effective separation of small particles in a solution.