AOAC SPIFAN Nutrients ERP (December 7, 2022)

For ERP/Working Group Use Only DO NOT DISTRIBUTE Fluor-04 (SLV) Resubmission FOR ERP USE ONLY DO NOT DISTRIBUTE

Table I: Repeatability (r) and Intermediate Precision (ip) Metrics for the Determination of Fluoride

s r

s ip

Sample Description

Sample Code Overall Fluoride Average (µg/100 g recon. product)

RSD r (%)

RSD ip (%)

Infant Formula Sample 1 or 2, 01517RF00 Infant/Adult Nutritional Formula II, (Milk/whey/soy-based) Infant Nutritional Formula, (Hydrolyzed milk-based) 921457651Z Adult Nutritional Formula (High protein) 01434RF00 Infant Formula Powder (Partially hydrolyzed soy based) 410457651Z

Infant Formula A

16.33

0.11

0.66

0.10

0.62

SRM 1869

14.81

0.48

3.08

0.16

1.10

RM 8260

3.48

0.43

11.87

0.27

7.68

RM 8261

10.28

0.44

4.04

0.14

1.36

Infant Formula C or F

4.74

0.47

9.44

0.17

3.61

Milli-Q Water

Blank

1.72

0.23

13.02

0.07

3.87

Red text = below LOD

Electrode potentials are affected by changes in temperature. Samples and standards must be within ± 1 o C of each other for accurate measurements. The average temperatures of the samples and standards in the SLV differed by less than 0.6 o C each day for either electrode (data not shown) . Accuracy All samples in the SPIFAN kit were spiked with three levels of NIST-traceable standard solution. The results from the overspike studies can be found in Table II . The spike recoveries (accuracy) range from 101.6 – 108.8%, meeting the SMPR requirements. The precision of the overspike samples was 1.0 – 1.6% RSD. Linearity Two calibration curves were required to measure the fluoride concentration in the SPIFAN samples. Both curves demonstrated good linearity over the standard range of 2 – 10 µg/ 100 g (low curve) and 10 – 200 µg/ 100 g (high curve). The average correlation coefficient for both electrodes were 0.9967 and 0.9997 (low curve, high curve) over 6 days (see Fluoride calibration

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