1.1 lab techniques Flashcards
Hazard definition
Anything which can cause harm to a person
Hazards examples
Corrosive chemicals
Heat or flammable substances
pathogenic organisms
Mechanical equipment
COSSH
Control of substances hazardous to health
CLEAPSS
consortium of local educational authority for the provision of science services
Risk definition
The likelihood of a hazard occurring
What is in COSHH
chemicals
Nanotechnology
Biological agents
Standard PPE
Safety goggles
Lab coat
Gloves
Long trousers
Closed toe shoes
Linear dilutions
A series of solutions which differ in concentration by an equal interval
Log Dilutions
A series of solutions which differin concentration by a constant proportion
Making up linear dilutions
Add equal intervals of solution into each test tube and make up to the same volume with water
making up log dilutions
add 1cm of solution from sample into test tube and make up to 10cm3, then use 1cm3 of test tube 1 and make up to 10cm3 in test tube 2 and repeat
Semi log graphs
A graph with a linear axis and a log axis
Advantages of linear dilution
Each concentration is made up individually so errors only affect one solution.
Application of log dilution
Log dilution down the concentration of a bacteria solution
Then count her number of colonies on an agar plate.
Multiply up and you can find the concentration of the original solution
Buffer solution definition
A solution which remains at a constant pH when small quantities of acid or base are added
colourimetry uses
percentage transmission used to measure turbidity
absorbtion to measure colour and concentration
What is a centrifuge used for
Separation of substances of different density
more dense substance in centrifuge
will form a pellet at the bottom of the tube.
What happens to the less dense substance in a centrifuge
It remains in the supernatant
Supernatant
The solvent in a centrifuge
Types of chromatography
Paper
Thin layer
Affinity
Paper chromatography
Uses a special type of paper as the chromatogram, since paper contains cellulose which is polar it will allow for non polar molecules to travel further up the paper.
Thin layer chromatography
Uses silica gel, cellulose or an absorbent material.
Affinity chromatography
Used to separate one specific protein from a mixture by sending the mixture through a column with specific antibodies which will bind to the specific protein. This will mean the specific protein remains in the column whilst other proteins pass through.