AOAC Final Action Methods in 2017

552 P ACQUETTE & T HOMPSON : J OURNAL OF AOAC I NTERNATIONAL V OL . 101, N O . 2, 2018

Table 4. ( continued )

Sample

1 a

2 b

3 c

4 d

5 e

6 f

Parameter

No. of outliers (individual replicates)

2

0

2

0

0

0

No. of accepted results

14

16

12

16

16

16

Overall mean of all data (grand mean) g

0.00330 0.00019 0.00019

0.0115

0.0813 0.0011 0.0030

0.00370

0.00340

0.162

S r

0.00015 0.00040

0.000057 0.000081

0.000034

0.00251 0.00434

S R

0.00011

h

RSD r RSD R

5.69

1.33 3.46

1.34 3.63

1.54 2.20

0.99 3.37

1.55 2.68

5.69

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Repeatability limit r (r = 2.8 × s r ) Reproducibility limit R (R = 2.8 × s R )

0.00053 0.00053

0.00043

0.0031 0.0083

0.00016

0.00009

0.0070 0.0122

0.0011

0.0002

0.0003

HorRat value

0.21

0.16

0.22

0.080

0.13

0.18

Repeatability limit SMPR for products Reproducibility limit SMPR for products

5

5

5

5

5

5

15

15

15

15

15

15

Selenium

Year of interlab test

2016

2016

2016

2016

2016

2016

No. of labs submitting results

8 0

7 3

7 2

8 0

8 1

8 0

No. of outliers (individual replicates)

No. of accepted results

16

11

12

16

15

16

Overall mean of all data (grand mean) g

0.000700 0.00010 0.00022

0.00550 0.00022 0.00036

0.0150 0.0011 0.0014

0.00180 0.00011 0.00014

0.00130

0.0305 0.0020 0.0020

S r

0.000041 0.000071

S R

h

7.00 h

6.10 h

6.43 h

RSD r RSD R

14.10 31.30

3.96 6.54

3.16 5.44

h

9.59

7.79

6.43

Repeatability limit r (r = 2.8 × s r ) Reproducibility limit R (R = 2.8 × s R )

0.00028 0.00061

0.00061

0.0029 0.0040

0.00031 0.00039

0.00012 0.00020

0.0055 0.0055

0.0010

HorRat value

0.92

0.26

0.45

0.27

0.18

0.34

Repeatability limit SMPR for products Reproducibility limit SMPR for products

5

5

5

5

5

5

15

15

15

15

15

15

a

Butter.

b

Cheese.

c

Whey Powder.

d

Whole-Milk Liquid.

e

Whole-Milk Powder.

f Whey Protein Concentrate Powder. g

The results are expressed in milligrams per 100 grams as-is for whole-milk liquid, butter, cheese, whey powder, and whey protein concentrate. For whole-milk powder, results are milligrams per 100 grams of the reconstituted powders (25 g in 200 g water), as for the nutritional powders given in Table 3. h Parameters that failed the SPIFAN SMPR criteria for nutritional products.

Mn. — No failures above the new recommended analytical range (two placebos and butter failed). Cr. — No failures (only 5/18 samples were above the SMPR limit of 0.002 mg/100 g in Table 3, and they all passed SMPR criteria; none of the dairy products contained measurable Cr). Se. — Repeatability for whole liquid milk and WPC was approximately 6% (one placebo and butter failed; below SMPR range). The recommended analytical ranges for Cu, Fe, and Mn had to be adjusted upward from the SMPR minimums as described in ref. 5 and shown in Table 2015.06D . Table S1, in the supplemental information, contains the raw data for all the SPIFAN and ISO/IDF matrixes. Average and normal RSDs are calculated for the 10 laboratories for each

from this same matrix caused problems in an earlier MLT (3). Likewise, we exclude the whey powder dairy ingredient, which did not seem to be adequately homogeneous, at least at the sample size chosen (0.3 g). The failures relative to SMPR were then as follows: Ca. — Repeatability for infant milk-based RTF was 5.7%. Cu. — No failures above the new recommended analytical range (three placebos and butter failed). Fe. — No failures above the new recommended analytical range (three placebos, butter, and whole milk failed). K. — Repeatability for butter was 5.8%. Mg, Na, and/or P. — No failures. Mo. — Repeatability for butter was 5.7%. Zn. — No failures (butter was below the SMPR range).