AOAC SPIFAN Nutrients ERP Review (March 14, 2019)

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

Figure 7 Chromatogram for the standard reference material SRM 1849a with horizontal baseline and peak height determination

K. Method validation (a) Selectivity and specificity. —The selectivity of the method was proved by comparing the retention time of fluoride in the samples with that from the certified fluoride standards as well as with spiked samples. The peaks of fluoride in the standards, the spikes, and the samples match with retention times of 7.5±0.5 min. Figure 8 shows an overlay of the SMPR 1849a, a spike, and two calibration standards.

Figure 8 Overlay of the chromatograms from the SMPR 1849a (black, 62.8 μg/kg/125.7 µg/100g) and a spiked SMPR 1849a (green, 115.6 μg/kg/230.7µg/100 g, spike concentration 158.7 µg/100g) with the standards 50 μg/kg (blue, 100 μg/100g) and 100 μg/kg (pink, 200 μg/100g)

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