Handling
Aliquot
Research use only. For in vitro research use only. Not for human or animal consumption. Not for human consumption, medical use, or personal application.
An aliquot is a measured portion divided out of a larger parent sample. In peptide work the parent is usually a vial that has just been reconstituted, and the aliquots are single-use volumes sealed into separate tubes before anything goes back to the freezer. Splitting trades one container that will be opened many times for many containers each opened once. The division is made while the material is at its most intact.
Why one early split beats repeated access
A stock vial reopened ten times puts all of its contents through ten warming and refreezing events; ten aliquots put each tube through one. Damage from freeze-thaw cycling accumulates, so confining it to a single early step limits how much of the lot is exposed at all.
The trade is not free. Every transfer invites volumetric error, contamination and loss on tube walls, and more tubes mean more labels to get wrong. Aliquoting earns its keep when a stock is drawn on over weeks, rarely when it is consumed in an afternoon.
Labelling that keeps a divided stock traceable
An aliquot inherits its parent lot number and is traceable only if that number travels with it. Record the lot, the diluent and the fill date on the tube, so material found months later can still be tied back to its certificate of analysis.
Volumes, concentrations and how long a divided stock may be held belong to your own written procedure, not to a general rule. Laboratory handling basics covers which of those variables need deciding before a vial is opened.
Frequently asked questions
- When is aliquoting not worth doing?
When the reconstituted volume will be used promptly, or when it is small enough that transfer losses and pipetting error cost more than the stability gained. Every split adds a handling step, and handling steps carry their own risk.
- Does an aliquot get its own certificate of analysis?
No. An aliquot is a portion of a lot, not a new one, so it carries the parent lot's documentation. That is why the lot identifier has to appear on the tube and not only on the original vial.
- Can dry material be divided instead of a solution?
Dividing a dry cake means weighing rather than pipetting, and it exposes the powder to ambient moisture each time. Bulk presentations such as raw powder are built around weighing; a fixed-mass lyophilised vial is not.
Updated 2026-06-01