engineer Benjamin Robins (1707–
1751) invented a whirling arm
apparatus to determine drag.
In 1864, the first dairy
centrifuge in order to separate
cream from milk.
In first continuous
separator, making its
“THE DEVICE USE TO SEPARATE HEAVIER PARTICLES FROM
THE LIGHTER ONE BY THE ACTION OF CENTRIFUGAL FORCE.”
●The principle component of a centrifuge is the rotor,
which is the moving part that spins at high speeds.
●Rotors can be fixed in position, or a centrifuge can use
multiple rotors fixed atop part called the spindle.
5. ● The centrifuge works on the principle of increasing
effective gravity to enhance the rate of settling of
suspended particles more dense than the buffer.
● we need to double the force on samples, increase the
rotation speed by 41%.
● After centrifuging, the liquid is called "supernatant“
and the solids at the bottom of tube are called
6. ● Centrifugal force :-
“a force, arising from the body's inertia, which to act on
a body moving in a circular path and is directed away
from the centre around which the body is moving.”
9. ●Fixed-angle :-
Fixed angle rotor centrifuges are probably the most
common type of this instrument encounter in the lab.
These centrifuges, in which tubes sit in a fixed and
angled position, are used in differential centrifugation
protocols. In these protocols, a series of centrifugations
at different speeds can be used to purify biological
specimens like animal cells.
● Ultracentrifuges :-
It can spin in excess of 70,000 rpm, which makes it well
suited for the isolation of small particles, like DNA or
10. MLI-mde 210, 311
• Glass centrifuge tubes can be used with most
solvents, but tend to be more expensive. They can
be cleaned like other laboratory glassware, and can
be sterilized by autoclaving.
• Plastic centrifuge tubes, especially micro-centrifuge
tubes tend to be less expensive. Water is preferred
when plastic centrifuge tubes are used. They are
more difficult to clean thoroughly, and are usually
inexpensive enough to be considered disposable
Centrifugation is a process by which a centrifuge is used
to separate components of a complex mixture.
By spinning laboratory samples at very high speeds, the
components of a given mixture are subjected to
centrifugal force, which causes more dense.
particles to migrate away from the axis of rotation and
lighter ones to move toward it. These particles can
sediment at the bottom of the tube into what’s known
as a pellet or the remaining solution, the supernatant,
can be further process.
13. Centrifugation of blood
●A centrifuge separates out blood components by their various
●The red blood cells (RBCs) are denser and move to the bottom
of the tube
●The plasma fraction is the least dense and will float as the top
14. ●The plasma fraction is the
least dense and will float as
the top layer.
●The "buffy coat“ which
contains the majority of
platelets will be sandwiched
between the plasma and
above the RBCs.
15. ●Removing fat from milk to produce skimmed milk.
● Removing water from lettuce after washing
it in a salad spinner.
● Separating particles from an air-flow.
● For clarification and stabilization.
● Separation of water particles from clothes while
spin-drying in washing machines.
● Separation of urine components and blood
components in forensic and research labs.
16. ● Ensure that centrifuge bowls and tubes are dry.
● Ensure that the spindle is clean
● Ensure that the rotor is properly seated on the drive shaft.
● Make sure that tubes or containers are properly balanced
in the rotor.
● Do not exceed the rotor’s maximum run speed.
● Close the centrifuge lid during operation.
● Make sure that the centrifuge is operating normally before
leaving the area.
● Make sure that the rotor has come to a complete stop
before opening the lid.