Laboratory glossary
Batch numbers and material traceability
An identifier linking units and documentation of a production batch, rather than the compound name or CAS number.
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The distinction that matters
Two variants with the same name may have different batches and documents.
What a batch is
A batch is material obtained under the same controlled conditions and processed as a homogeneous unit, including the relevant synthesis, purification and filling operations. Material within that batch is treated as equivalent for the stated controls. Two batches of the same compound are not automatically identical.
Each batch has a unique identifier printed on the vial and repeated in its documentation. That identifier is the traceability key connecting a particular physical vial with the analytical evidence describing its source material.
Analysis belongs to the batch
An analytical result describes the tested batch rather than the compound in the abstract. HPLC purity and ESI-MS identity results come from a sample of that batch. Declared vial content also relates to the applicable filling and content determination; a result or filling quantity should not be carried over to a different batch.
That is why certificates are batch-specific. Another batch’s certificate can be a valid document about different material. Before filing a certificate, compare its batch identifier with the vial label; if they differ, the certificate does not apply to that vial.
Handling decisions tied to batch identity
Treat the identifier as experimental information, not merely an administrative field.
- Changing batch partway through a series introduces a variable. Record it, and where the design permits reserve enough material from one batch for the full series.
- Do not merge aliquots from different batches into one bank without documenting their origins. The combined bank is no longer described by a single batch certificate.
- Reconstituted-container labels should identify compound, concentration, diluent, date and batch. Batch identity is difficult to reconstruct after the source vial is discarded, even if purchasing records remain.
- For unexpected dissolution or appearance, record the batch number so an investigation can distinguish a vial-specific observation from a production-wide issue.
Batch and specification are not interchangeable
Release depends on results meeting the applicable product specification. The criterion is shared across batches, while measured results vary within its allowed limits. Two batches can comply without having identical measured values.
Meets specification is therefore different from matches the previous batch. Comparative work may require the actual reported values and their methods, not only an acceptance limit. Review the relevant product and batch documentation.
Common confusion
A CAS number identifies a substance, and a catalog number or SKU identifies a supplier’s product presentation. Neither necessarily distinguishes one production from another. A batch number identifies a particular production and changes for subsequent material. Vials with the same SKU may have different batch certificates. Recording only a catalog number cannot reconstruct which batch was used.
How to record it
Batch exactly as printed, supplier, variant and associated document.