MCPD-02 Reviewer Forms (July 19, 2018)

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Reviewer 4

Were the recommendations/comments completed as requested by the ERP?

- Recommendation 1 : Address system suitability Modification in method answer ERP recommendation

- Recommendation 2: Verify the purity of the labelled standard with every run/batch Note added in section C address the concern raised. Check of purity is enough for each new preparation of standard and not necessarily within each analytical run. - Recommendation 3: Verify the response factors over the analytical range to demonstrate linearity on every system The method still highlights a single point calibration. The note added at the end of section C answer partially the recommendation. Importance of the target ions is also highlighted in the note of section B to ensure similar response factors is obtained between labelled standards and analytes. However, the procedure that is described (end of Section C, check of mixed working solution of isotope-labelled internal standard) should be part of the mandatory control steps after each new preparation of working solution. It should be fully integrated in the section working solution preparation, to ensure same response of isotope labelled internal standard and analyte in the GC-MS. The procedure in the note can be indeed understood as an optional check for laboratories implementing the method. - Recommendation 4a: Written in AOAC format – check for missing steps and information details Typo errors highlighted have been corrected and document gained in clarity. Missing information on evaporation steps and centrifugation speed have been partially added, as well as tolerance on given temperatures. Not all steps have been detailed: e.g. centrifuge conditions are clearly mentioned in D(1)c and D(3)b, but not explicitly given for D(1)e, D(1)f, D(1)g, D(2)b, D(2)c, D(3)c, D(3)e and D(4)b. When not mentioned, condition may refer to Note at the end of D(1). It would be beneficial to either detail conditions, or to place the note adequately in the document. - Recommendation 4b: Written in AOAC format – Add safety Safety advise and risk evaluation has been added in the document (cover page for general handling of chemicals, D(1)b for extraction of sample under pressure in glassware). - Comments: Individual comments from ERP have been addressed and answered either by modification of the manuscript or by giving sound justifications. The reagent section should be expanded to include CAS numbers. Specifically for the target compounds. Although some reagents are common in a laboratory, it would be beneficial for method transfer to include them, especially with grade requirements (e.g. methanol, toluene, tBME).

Recommendation for First Action Official Methods SM status:

Method MCPD-02 described meets SMPR. To accept with additional updates.

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