Aliquotting

Aliquotting is the process of separating a homogeneous sample into one or more smaller portions, called aliquots, that are of known volume and composition. Aliquots are intended to be representative of the original sample and can be analyzed separately or stored for later use. The practice is common across chemistry, biology, medicine, and environmental testing to enable parallel analyses, preserve samples, or manage variability.

In practice, aliquotting typically involves ensuring sample homogeneity, determining the desired aliquot volume, and using calibrated instruments such as micropipettes, volumetric flasks, or graduated cylinders. Steps include mixing if needed, dispensing precise volumes into properly labeled containers, avoiding cross-contamination, and maintaining appropriate conditions (temperature, light, and exposure) to preserve the sample. For biological or sterile samples, aseptic technique is essential. Documentation, including container labeling, lot numbers, and storage instructions, supports traceability.

Common applications include analytical chemistry and clinical assays, where aliquots allow multiple measurements or methods to be run on the same material; microbiology and molecular biology, where aliquots enable parallel experiments or plate preparations; and long-term storage, where aliquots reduce the need for repeated freeze–thaw cycles. Aliquotting also supports quality control by providing replicates and enabling stability testing.

Key considerations include container compatibility and surface interactions, potential adsorption of analytes to container walls, and sample stability under storage conditions. Contamination risk, pipetting accuracy, and proper record-keeping are important for ensuring that aliquots remain representative and reliable for future use.