An order number identifies a transaction, while a certificate usually describes a product, lot or submitted sample. Linking the two requires the supplied material’s identifiers. Saving a certificate beside an invoice does not by itself establish that the document belongs to that delivery.
Begin with the material received
Sigma-Aldrich’s document-search interface provides a certificate search using the lot or batch number, with a product-number field available as additional context. This illustrates the importance of material identifiers when retrieving the applicable document.Sigma-Aldrich — Document search: Certificates of Analysis (opens in a new tab)
Read the identifiers on the received material and the receipt record before attaching a certificate to the purchase. A planned lot on a quotation may differ from the lot actually delivered.
Record the product identifier, lot and supplier exactly, retaining meaningful prefixes and punctuation. If two documents use different codes, obtain or preserve the mapping instead of selecting whichever looks most familiar.
A website search result is a candidate document until its contents have been checked. Similar filenames and adjacent catalogue entries can still lead to the wrong certificate.
Allow one purchase to connect to several lots
| Purchase line and receipt | Received material | Document link |
|---|---|---|
| Order Q12, line 1, receipt A | Product P4, lot L1, two vials | Certificate C-L1 |
| Order Q12, line 1, receipt B | Product P4, lot L2, one vial | Certificate C-L2 |
| Order Q12, line 2, receipt A | Product P8, lot L7, one vial | Certificate C-L7 |
The example shows why one certificate per order is often an inadequate data structure. A single purchase line can be fulfilled in more than one receipt and from more than one lot.
The reverse is also possible: several orders may supply the same lot and share the same applicable certificate. Retain the distinct receipts while linking to the same document where appropriate.
If the certificate identifies only a laboratory sample code, the purchase record needs the additional sample-to-lot connection. The transaction reference cannot supply that missing relationship by itself.
Preserve the document and its retrieval context
Save the certificate with its original issuer, document identifier and version where present. Record where and when it was obtained so that a later reader can distinguish the saved evidence from a changing webpage.
Use a descriptive local filename as an aid, but retain the original identifiers inside the document record. Renaming a PDF does not correct an incorrect lot number printed within it.
When a revised certificate is issued, preserve the earlier copy and mark which version supersedes it. Check whether the correction affects material already used in experiments.
Check the link at the point of use
Make the applicable certificate reachable from the inventory entry used in the study. Researchers should not have to infer which attachment belongs to their vial from a long purchase-email chain.
Periodically test a few paths from experiment to container, receipt and certificate. This checks whether the record design works in practice without requiring repeated interpretation of every analytical result.
The resulting link supports traceability and document retrieval. It does not independently authenticate the report or prove that the physical contents match its description; those remain separate evidential questions.
Sources and further detail
- Sigma-Aldrich — Document search: Certificates of Analysis (opens in a new tab)
Current interface inspected: lot/batch search and optional product context. No certificate was submitted, altered or represented as independently authenticated.
Sources checked 20 September 2026. Inventory examples are hypothetical research records, not Novum stock, fulfilment procedures or validated laboratory systems. This article has not undergone independent scientific peer review.