AOAC OMA# 2011.14 (Final Action Review)-OMB

2011.14 (Oct. 2018) – MTE-03 Final Action Review FOR ERP USE ONLY DO NOT DISTRIBUTE

various concentrations (one of these below the lowest working standard and near the SMPR lower limit) as unknown samples. The linearity experiments were performed on three independent days for each laboratory. On each of 5 independent days, the reagent blank (not microwave digested) was analyzed as a sample and the limit of quantitation (LOQ) determined as the mean of blanks plus 10*s r . The LOQ was adjusted for dilution for RTF samples to obtain the corresponding LOQ in product. Finally, NIST SRM 1849a was analyzed in duplicate on one or more days. Laboratories were evaluated on linearity, LOQ, and accuracy with NIST 1849a using predetermined criteria. 1) The 3-day mean recovery for the standards analyzed as unknown samples must be 95-105%, or ≤5% residual error. The lowest point in the calibration curve at which the residual error did not exceed 5% was considered the practical limit of quantitation (PLOQ), below which the method may not be used. Each participating lab determined their PLOQ and sample dilutions could be adjusted if needed to comply with the PLOQ. 2) LOQ values for all 9 elements must be at or below the SMPR criteria. Exceptions may be made for Mn, Cu, and Fe LOQ values, which are more difficult to achieve at the low levels required. 3) Results from analysis of the NIST SRM should target the certified range with RSD r of ≤2%. Study materials .-Samples analyzed in the study included the AOAC INTERNATIONAL SPIFAN II Single Laboratory Validation Test Materials Kit (5; including 13 fortified nutritional products, 5 nutritional product placebos, and NIST SRM 1849a) provided by Covance Laboratories (Greenfield, IN) and the IDF matrix kit (salted