Transfer pipettes: moving drops or measuring accurately?

1 min read

In short

Simple transfer pipettes move small quantities where high accuracy is unnecessary. Printed graduations do not automatically make them precision devices. Defined volumes need suitable equipment and technique.

Material and measurement: Chemical and temperature; Product-specific approval; A scale ≠ precision.

Contents

Transferring versus dosing
Plastic or glass?
Prevent carryover
Questions

Transferring versus dosing

A suitable drop may suffice for a fresh slide; the same uncertainty may seriously affect analysis. Decide whether you need wetting, a subsample or a measured volume.

Drop count is not universal: liquid properties, outlet and angle affect size. “Twenty drops always equal one millilitre” is unreliable across products and liquids.

Plastic or glass?

Plastic versions often include an integral bulb. Glass Pasteur pipettes require an appropriate aid and can break. Choose for chemical and method compatibility. Never mouth-pipette.

Prevent carryover

Use separate pipettes where needed, avoid touching tips or dirty surfaces, do not return used tools to clean stock unless the method permits it, observe single-use restrictions and dispose according to material and contamination.

Read slides, pH subsampling and materials. Browse supplies.

Questions

Is a 3 ml pipette accurate up to 3 ml?: Nominal capacity does not establish adequate measurement uncertainty; check specification and task.
Why are there bubbles?: Air may have been aspirated, handling may be unsuitable or the liquid may foam. Use the demonstrated method.
Do first-year students need their own micropipette?: Normally only if expressly required. Universities usually provide these maintained instruments for practicals.