Pipetting Skills Practical

Question 1

Why is correct use of a pipette important ?

Answer 1

Help reduce test result variation
Reduce waste of expensive reagents

Question 2

Outline the steps to using a micropipette:

Answer 2

Set the required volume on the correct pipette

Attach the correct tip

Press plunger to ‘first stop’ outside of liquid to dispel air

Lower pipette tip vertically into liquid (slightly below surface) without touching container

Release plunger slowly to aspirate

Dispense liquid back into container to the first stop

Repeat aspiration 2-3 times to ‘wet tip’

Dispel into target container holding pipette at a 10°- 45° angle whilst tip is touching vessel wall

Press plunger slowly to ‘First stop’ to expel fluid, then carry on to ‘second stop’ to blow out

Eject tip safely into waste container

Question 3

How do you pipette viscous solutions ?

Answer 3

Reverse pipetting

Question 4

When should you work with a dilution series ?

Answer 4

When it is too difficult/ inaccurate to measure small amounts, and/or when using expensive chemicals such as antibodies, a series of dilutions is used instead

Question 5

How is liquid dispensed from a pipette ?

Answer 5

Liquid is confined to a disposable plastic tip and is dispensed by air displacement

Question 6

Why do you always work within the pipette volume ?

Answer 6

Going outside of range may damage internal mechanics

Question 7

What is a dilution series ?

Answer 7

A method used to systematically decrease the concentration of a substance by adding it to a series of solvent volumes

Helps create a range of concentrations that can be used for various experiments