SIG — correspondence log
Every enquiry the Institute made, why it made it, how it was answered and how long the answer took.
The Institute assesses documentation, not product. It has purchased nothing, tested nothing and inspected nothing. Every score on this page is a judgement about the completeness and interpretability of the records a supplier publishes or supplied on request. A high score means that a supplier documents its material well. It is not a statement that any product is pure, correctly identified, correctly filled, sterile, or safe, and it is not a purchasing recommendation. The Institute makes no purchasing recommendations.
§5Correspondence log
The Institute records every enquiry it makes to a supplier and the outcome of each. The log is published in full, in date order, whatever it contains: a dossier that reports only the information a supplier chose to supply would present the supplier's disclosure decision as the Institute's assessment. This is also the surface on which a supplier's own account of a question is published, in its own words, alongside the Institute's.
§5.1Enquiry log
Table 3. Correspondence between the Institute and SIG, in date order.
| Sent | Subject | Why the Institute asked | Outcome | Days to reply |
|---|---|---|---|---|
| 26 Nov 2025 | Request for the scope of a claimed accreditation | Accreditation is granted for named tests within a defined scope. | Answered in full | 12 |
| 17 Mar 2026 | Request for the chromatographic method underlying a reported purity figure | A purity percentage without its method is not comparable with any other purity percentage. | Answered with the underlying record | 5 |
| 10 May 2026 | Request for counter-ion and water determination on a named batch | Without both, a mass balance cannot be formed and the delivered peptide mass cannot be established. | Answered in full | 8 |
| 3 enquiries recorded, each answered. Correspondence was conducted by the Institute's secretariat in writing. The Institute holds no telephone contact and uses no messaging channel; a reader wishing to put the same questions should put them in writing through the supplier's own site. | ||||
§5.2Right of reply
Sigma-Aldrich (Shanghai) Trading Co., Ltd. was sent this dossier in draft and given twenty-eight days to respond before publication. A response is published in the supplier's own words where one is received. The Institute corrects errors of fact on evidence and does not alter a judgement because a supplier disagrees with it; a disagreement is published alongside the judgement so that a reader can weigh both.[1]
§5.3Putting the same questions
Every enquiry in the log above was put in writing and answered in writing. A reader who wants an answer about a specific batch should ask for that batch, by number, from the supplier direct; the Institute cannot answer for material it has not seen. SIG publishes its catalogue, its current stock and its contact route at the address below.
Put a batch enquiry to SIG at sigmaaldrich.org →
The link is marked nofollow and sponsored and carries no assessment. Quote the batch number printed on the vial; an enquiry without one cannot be answered specifically.
References cited on this page
References are numbered in order of first citation in this document. Each superscript in the text links to its entry below.
- International Organization for Standardization. ISO/IEC 17025:2017 General Requirements for the Competence of Testing and Calibration Laboratories. ISO/IEC Standard 2017;3rd edition. identifier not held by the Institute
Identifiers are reproduced only where the Institute holds them. Where a digital object identifier or PubMed identifier is not shown, the Institute has recorded the journal and year and has not constructed an identifier.