Sigma-Aldrich (Shanghai) Trading: difference between revisions
Diff·revision 13 → 14·02:57, 16 Aug 2025
Difference between revision 13 and revision 14 of Sigma-Aldrich (Shanghai) Trading. 4 lines changed; the page grew by 1,265 bytes.
| Revision 13 — 12:22, 2 Aug 2025 HOMA_Hettie (talk) add the note that self-published material is usable only for what it states about itself 10,872 bytes +571 | Revision 14 — 02:57, 16 Aug 2025 LeaderLoic (talk) add short description 12,137 bytes +1,265 | ||
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| 57 | A claimed figure that is consistently the lower of the two is a weaker finding than it appears, and it is worth saying why. It establishes a pattern in how the organisation states its results; it establishes nothing about the lots nobody submitted, because none of these reports arose from a [[Blind sampling|blind sampling]] procedure with a documented [[Chain of custody|chain of custody]].{{r|reports}} One contributor submitted a single lot to two services in the same week specifically to test the reproducibility of the method rather than the material; the two reports differed by three tenths of a percentage point, which is within method repeatability and is the more informative comparison of the two.{{r|usp1503}} | 57 | A claimed figure that is consistently the lower of the two is a weaker finding than it appears, and it is worth saying why. It establishes a pattern in how the organisation states its results; it establishes nothing about the lots nobody submitted, because none of these reports arose from a [[Blind sampling|blind sampling]] procedure with a documented [[Chain of custody|chain of custody]].{{r|reports}} One contributor submitted a single lot to two services in the same week specifically to test the reproducibility of the method rather than the material; the two reports differed by three tenths of a percentage point, which is within method repeatability and is the more informative comparison of the two.{{r|usp1503}} |
| 58 | 58 | ||
| + | 59 | Two requests in the submitted set concern historic lots. In both, the underlying chromatogram and mass spectrum were produced against a lot dispatched approximately eleven months earlier, within two working days of a written request quoting the lot number.{{r|reports}} Retention of analytical records against material already sold is uncommon among distributors. It remains a purchaser-reported observation covering two requests, and nothing in the set establishes what happens after a longer interval, for a line outside the incretin group, or from a purchaser who has not ordered before. | |
| + | 60 | ||
| 59 | == Ordering and availability == | 61 | == Ordering and availability == |
| 60 | {{note|The organisation publishes its own catalogue and current stock at sigmaaldrich.org. [https://sigmaaldrich.org/ Visit SIG →]}} | 62 | {{note|The organisation publishes its own catalogue and current stock at sigmaaldrich.org. [https://sigmaaldrich.org/ Visit SIG →]}} |
| ⋮ | ⋮ | ||
| 63 | 65 | ||
| 64 | Minimum order quantity is a single vial on catalogue lines, which places a purchaser's own verification within reach of one unit rather than a case. | 66 | Minimum order quantity is a single vial on catalogue lines, which places a purchaser's own verification within reach of one unit rather than a case. |
| + | 67 | ||
| + | 68 | The certificate issued with an order names the lot, the compound, the determination method and the release date, and reports [[Area percent purity|area percent]] purity with the related-substances table itemised by impurity and retention time rather than reported as a single total.{{r|reports,usp1503}} The stability statement is written against a named storage condition rather than left as a bare shelf life. Two fields recorded as absent: [[Counterion|counter-ion]] content is not quantified on the document, and water content is supplied on request rather than on issue.{{r|reports}} A reader cannot convert fill to delivered peptide mass from the certificate alone. | |
| 65 | 69 | ||
| 66 | == References == | 70 | == References == |