AOAC SPIFAN Nutrients ERP Review (March 14, 2019)

Fluor-03 (Feb. 2019) FOR ERP USE ONLY DO NOT DISTRIBUTE

Table 9 Determination of the instrument detection limit determined in spiked UPW

No. UPW 0.5

F- (µg/kg)

1 2 3 4 5 6 7 8 9

0.5171 0.5189 0.5443 0.5598

0.562

0.5624

0.566

0.5725 0.5845 0.5957

10

AVG (μg/kg) SD (μg/kg)

0.56

0.025

LOD (µg/kg) LOQ (µg/kg)

0.64 0.81 1.27 1.63

LOD FIN LOQ FIN

(µg/100g) (µg/100g)

(f) Reproducibility RSD R . —To determine the method precision all samples were analyzed in duplicate on six different days (day-to-day reproducibility). Thereby the sample preparation and analyzes were performed by two different analysts and with the IC instrument using two different columns (see Table 10 and Annex C). The RSD R was calculated from the determined average concentrations and the standard deviation. Additionally from two examples (SRM 1849a and Hipp) representing each matrix type, i.e. solid infant formula and ready-to-feed liquid, the with-in day variability was determined, i.e. repeatability. Thereby 5 (SRM 1849a) and 8 (Hipp) samples, respectively, were freshly prepared and analyzed within a short timeframe (see Table Table 11 ) and the RSD calculated. The reproducibility (RSD R ) span a range of 5 to 12% and meets the SMPR criteria of ≤15%. The repeatability (RSD r ) for the solid infant formula determined for the SRM 1849a is 3.8% and for the ready-to-feed liquid 2%, meeting the SMPR requirements (≤8%) [4] . Definition of reproducibility and repeatability according to AOAC SMPR®2014.016 [4] : Reproducibility RSD R : The standard deviation or relative standard deviation calculated from among-laboratory data. Expressed as the % reproducibility relative standard deviation (%RSD R ). In our method related to the data collected from analyzes of the different samples on six different days using two different columns and resulting from preparation by two different analysts = day-to-day reproducibility. Repeatability RSD r : Variation arising when all efforts are made to keep conditions constant by using the same instrument and operator, and repeating during a short time period. Expressed as the % repeatability relative standard deviation (%RSD r ). Refers to the analyzed examples for each sample matrix prepared freshly and analyzed within a short time period = with-in day variability. /repeatability RSD r

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