W1,2 laboratory equipment Flashcards
thermal equipment
carefully monitored and frequent temperature checks cleaning and drefrosting are required
fridges 4 degrees
lab freezers0 -70 or -20
water bath
used to warm samples and reagents to a particular temp water baths provide a constant temperature that is thermostatically controlled. heating coil heats water to temp
they need to be changed frequently and washed a certain way
metal heating block
warms samples and reagents less constant than water bath but easier to clean
incubators
anhydric or waterjacketed
waterjacketed-allow more even heated distribution and rapid temp recovery after door has been opened
convection also used or a fan to circulate air
ovens
same as incubators but hot
biological safety cabinets
prevents exposure to infectious aerosols it also may be airborne bacteira they have special filters called HEPA high efficiency particulate air filters dense and have a standard efficieny of removing particles 0.3 micro meters in size
uv light and bsc
light bar of uv light and it disinfects the air and contaminated surfaces. it will cause damage to eyes and must be turned off if using bsc and it should only be used when no one is in the room
laminar flow safety cabinet bsc
common for handling infectious material
sash opening-moves up down
exhaust air goes through hepa filter and is recylced
how laminar flow bsc safety cabinet works
sheets of air created by air flow protect the work surface from airborne microorganisms by preventing escape but gowns and gloves must be worn
use of bsc safety rules
keep in low traffic area uv lamp off no centrifuge disrupt airflow no burners clean certification procedures re
chemical fume hood
draw away gases fumes
have a sash a duct fan and stack filters
use negative pressure vacuum
air drawn from cabinet into duct then outside
turn of for 15 mins before and leave on 15 min after use
what does a centrifuge do
accelerate gravitational separation of substances
red cells forced to bottom plasma floats on top– separates mixtures with different density components
rcf
relative centrifugal force - force required to separate two phases
rcf=krn(squared)
k=1.118 (10^-5)
r= radius in cm from center of rotation to bottom of test tube
n =speed of rotar
max rcf is the force at the bottom of the tube
decrease the time needed to centrifuge a specimen if?
you increase the rpm
small centrifuge
increased time is needed to centrifuge a specimen since raidus is smaller and a high rcf cannot be achieved
serum or plasma sample for chemical analysis being centrifuged
will be spun using a high rcf for a longer time to ensure all cells have been spun to the bottom of the test tube
urine sample centrifuge
centrifugation at a lower rcf for less time to ensure the cellular meterial is still intact for microscopic analysis
centrifuge components
timer-times speed-set by potentiometer trachometer-indicates speed of rotor brake-reverse polarity causing to slow sealed bearings-dont require lubrication brushes-electrical contact to commutator rotor head-mounted on central spindle and spinds specimen cups or buckets trunnion rings- hold buckets in head cups or buckets-hold test tubes
high speed centrifuge
airfuge spins 90,000 rpm and used to clear serum of chylomicrons
how to balance centrifuge
must be balanced in opposition across central rotor when loading centrifuge
imbalance cause vibration
1. 2 similar tubes opposite eachother
2. if you have a tube that does no have a matching tube based on size shape and make you can make a water balance by finding a tube of similar size and shape and filling it with water
3. load tubes so that opposing buvkets have equal number of tubes and are balanced across the rotation axis
safety precautions for centrifuge
dont use break turn off let come to complete stop dispersion of aerosols wait 30 minutes use sealed dome shields safety trunnion cups auto lock
top load balances
weigh to 2 decimal places
analytical balances
weight to 4 decimal places
vortex
mixes sample or reagent
quick whirling motion
