AOAC SPIFAN Nutrients ERP (December 7, 2022)

Fluor-06 (SLV) 10-2022 FOR ERP USE ONLY DO NOT DISTRIBUTE

Table 10. Repeatability data of five different unspiked reference materials. Replicate SRM1869 SRM1849a NIST10175

RM8260

RM8261

1 2 3 4 5 6

1.25 1.24 1.24 1.22 1.25 1.22

1.39 1.44 1.42 1.44 1.44 1.44

0.345 0.348 0.344 0.345 0.333 0.346

0.189 0.179 0.186 0.181 0.193 0.189 < 0.2

0.923 0.910 0.921 0.900 0.906 0.915

Average (mg/kg)

1.2 0.9

1.4 1.4

0.3 1.5

0.9 1.0

RSD (%)

2.9

5.7 Reproducibility For determination of the reproducibility five different unspiked samples containing fluoride at levels of 0.2–1.5 mg/kg were analysed in duplicate on six days by one technician on the same instrument. The results are shown in Table 11.

Table 11. Reproducibility over 6 days by one technician in duplicate. Day SRM1869 SRM1849a NIST10175

RM8260

RM8261

1 2 3 4 5 6

1.260 1.287 1.245 1.255 1.254 1.216

1.475 1.509 1.473 1.484 1.423 1.479

0.340 0.360 0.320 0.340 0.308 0.342

0.222 0.196 0.154 0.193 0.169 0.179

1.013 1.006 0.906 0.983 0.821 0.906

Average (mg/kg)

1.3 1.8

1.5 1.9

0.3 5.5

<0.2

0.9 8.0

RSD (%)

12.8*

* Outlier influences the value of the sample according to the Grubbs outlier test

The relative standard deviation (RSD) is ≤ 8% for all samples except for one sample (RM8260). However, a Grubbs outlier test showed that this serie contained an outlier and the value was also below LOQ range.