Definition
An aliquot is a measured fraction of a larger sample. In peptide work, aliquoting usually means dividing a freshly reconstituted stock solution into several small, single-use tubes that are frozen separately. Each experiment then thaws only the portion it needs, while the remainder stays undisturbed. This limits freeze-thaw damage, reduces contamination from repeated opening, and keeps concentration consistent across experiments. Low-binding polypropylene tubes reduce losses of hydrophobic peptides to plastic surfaces. Each aliquot should be labelled with the peptide, concentration, diluent, batch number and date. Dividing the dry powder is harder, because weighing small masses of hygroscopic lyophilised material accurately requires a controlled environment and a microbalance.