AOAC Final Action Methods in 2018

Table 2011.14C. Interlaboratory study results for iron (Fe)

Original validation (2011)

Matrix

Mean, mg/kg Rec., % s r a

RSD r

b , % s

R c , mg/kg RSD R

d , % HorRat

No. of labs e Outlier labs f

Chocolate milk powder Dietetic milk powder 2

164.77

97

6.72 2.51 1.36 0.65 0.93

4.08 3.02 1.81 4.17 1.89

11.25

6.83 5.56 4.42

0.92 0.68 0.53 1.18 0.35

9 9 9 8 8

NS g

83.11 75.18

102

4.62 3.32 1.95 1.54

NS NS 6C 2C

Infant cereal

94 95 91

Peanut butter NIST SRM 2387 Wheat gluten NIST RM 8418

15.65 (16.4) h 49.29 (54.3) h

12.45

3.12

Matrix extension (2017)

Mean, mg/100 g i

SRM 1849a Whole milk

17.4 (17.6)

99

0.227 0.000

1.3

0.755

4.34

0.59 1.69 2.58

12

0 2 0 0 2 1 3 1 0 1 0 2 3 1 1 2 2 1 1 0 1 1 0 3 1

0.016 0.033 0.338 0.662

ND j

16 21 37

0.01 0.02

35 49 59

5 7 9 7 4 5

Whole milk powder

ND 0.01 ND 0.13 ND 0.021 ND 0.02 ND 0.015 ND 0.19 ND 0.074 ND 0.126 ND 0.04 ND 0.001 ND 0.048 ND 0.026 ND 0.053 ND 0.001 ND 0.015 ND 0.035 ND 0.014 ND 0.042 ND 0.048 ND 0.027 ND 0.002 ND 0.019 ND ND

Whey powder

0.2

4.4

Whey protein concentrate

3.13

0.11

16.3

1.35

Butter

0.03

ND

ND

ND

ND

Cheese

0.174 0.615

10

0.030 0.058 0.312 0.141 0.169 0.075 0.006 0.093 0.104 0.066 0.003 0.101 0.081 0.082 0.084 0.081 0.107 0.003 0.096

20

1.34 0.78

Adult powder, low fat

2.41 7.81

9.44 12.8

11 12 11 12 10 11 11 10 10 11 12 11 11 12 6 6

Adult RTF, high fat

2.43

1.3

Adult RTF, high fat placebo

0.454

16

31

2.44 0.81 1.22 0.81 0.72 1.21 0.52

Adult RTF, high protein

2.05

6.14

8.26 15.4

Adult RTF, high protein placebo

0.489 0.044

8.2 3.3

Child milk powder placebo

15

Child milk powder

1.17

4.11 3.61

8

Child elemental powder Infant elemental powder

0.724 1.132 0.028 1.008

14.3

4.7

5.8

Infant elemental powder placebo

2.836

11.791

0.608

Infant PH powder milk Infant PH powder soy Infant powder FOS-GOS

1.45 2.88 2.58 3.42 3.81

9.97

0.88

1.23

6.6

0.6

0.543

15

1.21 0.62 0.59 0.73 0.82 1.02

Infant powder milk Infant powder soy

0.24 1.26 1.35

6.81 6.48

Infant RTF milk

2

7.9

Infant RTF placebo

0.018 0.808

12

17

5

Toddler powder

2.38

11.9

11

a  s r = Standard deviation for repeatability (within laboratory). b  RSD r = Relative standard deviation for repeatability. c  s R = Standard deviation for reproducibility (among laboratories). d  RSD R = Relative standard deviation for reproducibility. e  Reporting laboratories minus outliers. f  C = Cochran outlier; SG = Single Grubbs outlier; DG = Double Grubbs outlier. g  NS = Not significant. h  Value in parentheses = Certified or reference values. i  Results expressed as mg/100 g for ready-to-feed liquids as-is or reconstituted powders (25 g in 200 g water) or liquid concentrates (1:1 dilution by weight). j  ND = Not determined.

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