Micropipettes Why they are useful How they work How to care for them

Micropipettes

Why they are usefulHow they work

How to care for them

Micropipettes are essential equipment in a modern biology lab

• For moving liquids from container to container

• Can measure tiny volumes, very precisely

• Come in a variety of sizes

• All require special disposable tips

• They are fragile and expensive

Micropipettes have different volumes

• P20: 20 microliters (=20 uL) max vol.• P200: 200 uL max.• P1000: ____uL max vol = ______

Volumes adjustable with dial

Micropipettes have different volumes

• P20: 20 microliters (=20 uL) max vol.• P200: 200 uL max.• P1000: __20uL max vol = _1mL__

Volumes adjustable with dial

Parts of a mircopipette

1. Volume adjustment2. Tip ejector button3. Plunger4. Adjustment threads5. Volume indicator

window6. Tip ejector bracket7. Shaft8. Disposable tip

Pipette tips

• Different tips for different kinds of pipettes

• Micropipettes are never used without an appropriate tip

How micropipettors workPipettes have

two springs“First stop”:

calibrated volume

“Second stop”: maximum volume of pipette

What is the volume indicated?

What is the volume indicated?

6.84 uL 132.5 uL 264 uL=____mL

How to use the pipette

A: Press plunger down to FIRST STOP BEFORE putting in liquid (make sure you adjusted to the right volume!)

B: Release plunger slowly, taking up correct volumeC: Put tip into new tube and press plunger to SECOND

STOP, expelling liquidD: Remove tip from liquid BEFORE releasing plungerE: Release plunger and eject tip

How to take care of the pipettes

• Never use a pipette without a tip• Never adjust a pipettor beyond its maximum (or

minimum) volume range• Never place a pipet on its side with liquid in the tip

What is wrong with this picture?

Pressing the tip ejector button

• Note: tip ejector doesn’t always work with certain tips