2. Basic Laboratory Equipment Flashcards
What is RCF?
RCF - Relative Centrifugal Force
Is the force required to separate two phases. Units expressed at g (number of times greater than the force of gravity)
What is the formula for RCF?
RCF = Krn^2
K is 1.118 X 10^-5
r is radius in cm
n is speed of rotation
How is the time required to separate the particles determined?
Rotor speed, radius of the rotor, effective path length travelled by the particles (how much liquid in a tube)
Can decrease the time by: increasing speed, increasing radius, decrease the amount of liquid
What are the different components of a centrifuge?
Timer Speed control Tachometer (speed of rotor revolutions per min rpms) Brake Sealed bearings Brushes Trunnion rings Cups or buckets
What are the different types of centrifuges?
Bench-top
Floor
Refrigerated or heated
High speed (airfuge)
How do you balance a centrifuge?
Balance opposite of each other, similar tubes with similar volumes
Can use water balances
Imbalance causes dangerous vibration
What is the purpose of centrifuges?
To separate mixtures (solid/liquid or liquid/liquids with different densities)
Accelerated gravitational separation
What are balances used for?
Used to measure amounts of a substance
Tare button stabilizes the balance to zero
Use face shield when working with a balance
What are the purpose of incubators?
Water jacketed incubators provide even heat distribution and rapid temperature recovery through convection air flow.
Ovens - higher temp
Water baths
What is the purpose of fridges/freezers?
To preserve specimens if ever needed in the future
Refrigerators - 4 degrees
Freezers - -70 and -20 degrees
What do you do when using or hooking up compressed gas tanks?
Strap it securely to counter
Be sure the regulator is correct
Make sure all connections are tight
Never oil or grease valves
What do you do when transporting gas tanks?
Remove regulator and put on protection cap
Use a trolley with safety strap
Do not allow tanks to hit each other
