AOAC Final Action Methods in 2018

Table 2011.14B. Interlaboratory study results for copper (Cu)

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

5.92 6.19 2.01

NA h 101

0.09 0.19 0.10 0.19 0.13

1.57 3.06 4.98 3.84 2.27

0.29 0.38 0.24 0.35 0.27

4.97 6.12

0.41 0.50 0.81 0.56 0.39

9 9 9 9 9

NS g

NS NS NS NS

Infant cereal

NA

11.72

Peanut butter NIST SRM 2387 Wheat gluten NIST RM 8418

4.98 (4.93) i 5.64 (5.94) i

101

7.08 4.77

95

Matrix extension (2017)

Mean, mg/100 g i

SRM 1849a Whole milk

1.95 (1.98)

98

0.053 0.000

2.71

0.099 0.005 0.004 0.024 0.025 0.030 0.007 0.018 0.004 0.016 0.005 0.002 0.005 0.007 0.004 0.005 0.006 0.004 0.008 0.006 0.004 0.003 0.003 ND 0.01

5.09 78.2 71.3 48.5 20.7 56.1 9.97 7.51 ND

0.50 3.27 2.91 2.72 1.33 3.20 0.59 0.54 1.71 2.23 1.13 0.57 0.56 0.49 3.66 0.47 0.53 0.51 0.71 0.48 0.51 2.68 0.59 ND 0.6

12

0 2 0 0 0 0 1 0 0 0 0 0 1 0 0 1 0 1 0 0 1 0 1 2 0

0.007 0.006 0.049 0.122 0.023 0.054 0.071 0.239 0.009 0.184 0.011 0.006 0.111 0.046 0.082 0.004 0.056 0.063 0.047 0.061 0.068 0.046 0.004 0.029

ND j

4.1

7

Whole milk powder

ND 0.001 ND 0.004 ND 0.008 ND 0.004 ND 0.002 ND 0.004 ND 0.002 ND 0.006 ND 0.001 ND 0.001 ND 0.005 ND 0.003 ND 0.003 ND 0.001 ND 0.001 ND 0.004 ND 0.002 ND 0.002 ND 0.004 ND 0.001 ND 0.001 ND 0.002 ND ND

20.7

10

Whey powder

8.4

9

Whey protein concentrate

6.24

11

Butter

ND 7.6

6 9

Cheese

Adult powder, low fat

2.57 1.82

12 12 12 12 12 11 12 12 11 10 12 12 11 12 11 10 12 8

Adult RTF, high fat

Adult RTF, high fat placebo

20

39

Adult RTF, high protein

3.37 6.39

8.7

Adult RTF, high protein placebo

50

Child milk powder placebo

10.37

27.4

Child milk powder

4.21 7.52 3.84 25.9 1.73 5.82 4.07 2.71 5.16 2.34 32.9 5.25

9.0

Child elemental powder Infant elemental powder

10.1

8.2

Infant elemental powder placebo

95

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

8.1 9.1

9.18 12.3 8.12

Infant powder milk Infant powder soy

Infant RTF milk

9.1

Infant RTF placebo

71

Toddler powder

11.3

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  NA = Not available. i  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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