AOAC SPIFAN Nutrients ERP Reviewer Forms (December 7, 2022)

FOR EXPERT REVIEW PANEL USE ONLY NOT FOR DISTRIBUTION

• Spiked Precision. Nominal spiking levels of 5 mg/100g, 50 mg/100g, and 100 mg/100g were completed in triplicate on three days using the following matrices: NIST 8261 (adult nutritional), NIST 10175 (infant formula, partially hydrolyzed soy), and NIST 1869 (infant formula, milk/whey/soy). This is the same data used for accuracy assessment (point #2 in Accuracy/Recovery section above). All RSD r met SMPR target (≤5%), with the range of 0.7% - 1.7%.

Reproducibility (RSD R ):

RSD R was not assessed, although intermediate precision (RSD iR ) from two different labs was presented for 6 of the 7 matrices with innate repeatability data. Sample SPIFAN DOMY545 (AN, RTF) was omitted from the RSD iR evaluation. The range of RSD iR for the tested samples is 1.3% - 6.7%, which is below the SMPR RSD R target. These data indicate the MLT RSD R will likely be within the SMPR target. Questions for authors: The between day precision for sample SPIFAN DOMY545 (calculated by reviewer) is 8.4 %RSD. This %RSD is higher than the other presented intermediate precision data. The higher %RSD for SPIFAN DOMY545 is driven by the lower results for Day 2, compared with the other precision days. The values for SPIFAN DOMY545 Day 2 replicated within day, which is why the repeatability was not impacted by the lower Day 2 results. What was the suspected cause for the lower Day 2 results for sample SPIFAN DOMY545? Why was sample SPIFAN DOMY545 eliminated from the inter-lab study?

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