SECOND LECTURE ON BIOLOGICAL AND CHEMICAL INSTRUMENTATION GLT 303
The Centrifuge sediments particles (cells, bacteria, and
parasites), suspended in fluids by exerting a force greater than that of
gravity. The greater the outward pull due to rotation, i.e. due to centrifugal
force, the more rapid and effective the sedimentation. Heavy particles sediment
first followed by higher particles. Centrifugal force increases with the speed
of rotation i.e. revolution per minute (R.P.M) and radius of rotation. The
actual sedimentation achieved at a given speed depends on the radius of the
centrifuge. Most techniques requiring centrifugation will usually require or
will specify the required relative centrifugal force (R.C.F), expressed in
gravity. For example R.C.F of 200g refers to a force 200X force of gravity.
Most manufacturers specify both the required/maximum relative centrifugal force
and motor per minute (R.P.M).
TYPES
OF CENTRIFUGE
1.
General purpose bench
2.
Micro-hematocrit
1.
General
purpose bench:
i.
It sediment cell, bacterial and parasites in the
body fluids for microscopic examination of blood, urine and cerebrospinal
fluids.
ii.
It is used to obtain serum, red cells, and
perform emergency compatibility test of cross matching.
iii.
To perform parasite concentration techniques.
iv.
To obtain serum, or plasma to anti-body testing
and chemical chemistry test.
2.
Micro-hematocrit:
i.
It is needed in the laboratory to diagnose and
monitor anemia when a reliable measurement of hemoglobin is not possible.
ii.
To measure packed cell volume (P.C.V.).
iii.
To calculate mean, cell hemoglobin concentration
in the investigation of ion deficiency and other form of anemia.
iv.
To perform micro hematocrit concentration technique
v.
To detect motile trypanosome and micro-Philaria.
MODE
OF OPERATION/STEPS IINVOLVED IN USAGE
1.
Open the cover/lid of the centrifuge.
2.
Check that the bucket/the tube holders are
correctly positioned.
3.
Make sure the content of each side of the
centrifuge are balanced.
4.
Add water or weak disinfectant solution to the
empty bucker using wash bottle to balance the weight.
5.
Cover the lid and set the centrifuge to the
appropriate rotor per minute (R.P.M) of choice. Start timing and press the stop
button when the required cycle is complete.
6.
Wait for the instrument to stop
7.
Remove the sample
8.
Commence the analysis.
CARE
AND MAINTENANCE
1.
Clean the centrifuge and tube-holders regularly
based on usage.
2.
Do not use corrosive cleaning flit.
3.
When centrifuging corrosive or alkaline samples
in a metal bucket, make sure the bucket are cleaned immediately.
4.
Examine regularly the electrical flex for signs
of wear and tear.
5.
Check the plug for loosed connections.
6.
At least every three months, check the metal
part of the centrifuge for corrosion, damage, and cracks.
7.
Place the centrifuge on a firm desk and out of
direct sunlight.
8.
Read the manufacturers instruction manuals
before usage and when newly purchased.
9.
Must have a stock record that shows the usage
and maintenance of the equipment/instrument (centrifuge).
FACTORS TO CONSIDER WHEN
PURCHASING A CENTRIFUGE
1.
Cost of centrifuge.
2.
What you want to use it for.
Assignment
Draw
the structure of a centrifuge.
Tags
Assignment
Biological and chemical instrumentation GLT 303
bioloical and chemical instrumentation assignment