Draft standard CEI-MS-02: Confirmation of peptide identity by… — submissions
The 6 submissions received, published in full with declared interests and secretariat responses.
§2Submissions and responses
6 submissions were received. Each is published in full below with its declared interest, the secretariat response and the disposition. The Institute publishes submissions it did not accept in the same form as those it did.
A determination does not record the version of the standard it was made under
The respondent notes that CEI-MS-02, Confirmation of peptide identity by liquid chromatography–tandem mass… will be relied on to distinguish a deletion sequence from the intended peptide, and submits with that in view.
The respondent states that the standard will be revised and that results reported under different versions will circulate together, indistinguishable from one another.
The respondent proposes that the standard identifier and version be carried on the face of every determination.
The secretariat accepts this submission. A conformance claim against an unspecified version is not a conformance claim.
Every determination reported under this standard now carries the standard identifier and version on its face, and a claim of conformance that does not identify the version is recorded by the Institute as not conformant.
Nothing requires a laboratory to demonstrate ongoing performance
This submission addresses the draft of CEI-MS-02, Confirmation of peptide identity by liquid chromatography–tandem mass… and is made from an analytical rather than a regulatory standpoint.
The respondent states that suitability criteria assessed within a run demonstrate that the run worked and not that the laboratory performs consistently over time.
The respondent proposes participation in a proficiency scheme as a condition of conformance.
The secretariat accepts this submission in part. A trend requirement on system suitability data is added. Proficiency scheme participation is not made a condition of conformance, for the same reason competence requirements are not.
The standard now requires that system suitability results be trended across runs and that a determination report whether the trend was within the laboratory's stated limits, which places the demonstration inside the document the Institute can read.
The standard does not state that a determination on one unit says nothing about the batch
The respondent read the draft of CEI-MS-02, Confirmation of peptide identity by liquid chromatography–tandem mass… and has confined this submission to a single requirement.
The respondent states that determinations under this standard are generally performed on a single unit and that certificates then travel with every unit of a batch, so that a single-unit result is routinely read as a batch result.
The respondent proposes that the standard require a sampling statement on the face of every determination.
The secretariat accepts this submission. The inference from unit to batch is the most consequential unstated assumption in supply documentation.
Every determination made under this standard now carries a sampling statement recording how many units were sampled, from what population and by what plan, and the standard states that a determination on a single unit supports no inference about any other unit.
Results are reported without an estimate of measurement uncertainty
The respondent submits on the draft of CEI-MS-02, Confirmation of peptide identity by liquid chromatography–tandem mass…. An identity determination either distinguishes the compound from its near neighbours or it does not, and a standard should be explicit about which it achieves.
The respondent, an analytical chemist, states that a figure reported to one decimal place implies an uncertainty the standard nowhere estimates, and that two determinations differing within the uncertainty will be read as a difference.
The respondent proposes that an uncertainty budget be required for every determination.
The respondent has read submission 002 above and makes this submission independently of it.
The secretariat accepts this submission in part. A repeatability figure and a stated reporting precision are required. A full uncertainty budget is not, because the standard is written to be usable by laboratories that do not maintain one and the requirement would exclude them without improving the reading.
Every determination now reports the repeatability observed in the run, the reporting precision, and a statement that two results differing by less than the stated repeatability are not distinguishable by this method.
The document set should be published in translation
The respondent’s comment on the draft of CEI-MS-02, Confirmation of peptide identity by liquid chromatography–tandem mass… arises from what is achievable on instrumentation in general use.
The respondent notes that the assessments concern compounds supplied internationally and that publishing only in English restricts access to the assessment to readers who work in it.
The respondent proposes machine translation of the document set as an interim measure, with human review of the certainty language.
The secretariat does not accept this submission, and records that the underlying point is sound and that the proposed remedy is the difficulty.
A translation whose certainty language has drifted is a different assessment carrying the Institute's name, and the Institute cannot review translations it does not have the capacity to review. The documents remain in English. The submission is published in full because the access problem it identifies is real and unresolved.
Nothing addresses the container the material was held in
Having read the draft of CEI-MS-02, Confirmation of peptide identity by liquid chromatography–tandem mass…, the respondent puts one point to the secretariat.
Adsorption to the container and oxidation in the headspace both change what is measured, and both depend on the container rather than on the material. The standard treats the vial as neutral.
The respondent proposes that container type and headspace atmosphere be reported where they are known.
The secretariat accepts the reporting requirement where the information is held and declines to require it where it is not.
Container type and headspace atmosphere are now reported where known, and recorded as not held where they are not, rather than omitted.
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.