AOAC Final Action Methods in 2018

Table 2011.14E. Interlaboratory study results for magnesium (Mg)

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

1746.74 439.31 859.48 1714.02 (1680) h

98 99 98

38.46

2.20 1.27 3.91 3.32

51.03 13.37 35.38 73.68

2.92 3.04 4.12 4.30

0.56 0.48 0.71 0.82

8 9 7 8

2SG NS g

5.57

Infant cereal

33.62 56.83

2, 6DG

Peanut butter NIST SRM 2387

102

2SG

Wheat gluten NIST RM 8418

482.05 (510) h

95

8.52

1.77

16.53

3.43

0.54

9

NS

Matrix extension (2017)

Mean, mg/100 g i

SRM 1849a Whole milk

163 (165)

99

2.95

1.81

5.68

3.48

0.66 1.08 1.17 0.88 0.83 2.71 1.20 1.00 0.70 1.66 0.64 0.80 1.29 1.16 0.60 1.37 0.59 0.57 1.17 0.64 0.62 1.10 0.84 0.79 1.13

12 11 11

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

10.2 9.24

ND j

0.300

2

0.9

9

Whole milk powder

ND 0.352 ND 3.13 ND 0.815 ND 0.164 ND 0.511 ND 0.218 ND 0.515 ND 0.05 ND 0.67 ND 0.019 ND 0.033 ND 0.347 ND 0.107 ND 0.19 ND 0.08 ND 0.052 ND 0.087 ND 0.105 ND 0.115 ND 0.24 ND 0.177 ND 0.062 ND 0.064

3.81 1.55 1.11

0.873

9.44

Whey powder

202

9.1

4.5

9

Whey protein concentrate

73.4 1.94 19.9 13.1 39.5 1.97 32.8 1.68 1.86 9.34 5.37 5.13 5.07 6.54 4.54 5.01 8.07 6.25 3.33 5.96 4.3

3.61

4.92 27.7

11

Butter

8.5

0.537 1.720 1.001

9 9

Cheese

2.57 1.67

8.7

Adult powder, low fat

7.65 4.56 16.9 4.26

12 12 11 12 11 12 10 11 10 11 10 10 12 11 10 12 9 8

Adult RTF, high fat

1.3 2.8

1.8

Adult RTF, high fat placebo

0.33

Adult RTF, high protein

2.03

1.4

Adult RTF, high protein placebo

1.1

0.141 0.247 0.875 0.283 0.623 0.264 0.221 0.651 0.263 0.277 0.732 0.453 0.249

8.4

Child milk powder placebo

1.75 3.72 1.99

13.29

Child milk powder

9.37 5.27 12.1 5.22 5.14 9.95 5.54 9.07 7.24 5.8

Child elemental powder Infant elemental powder

3.6

Infant elemental powder placebo

1.58

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

1.2

1.34 2.32

Infant powder milk Infant powder soy

2.3

2.98 2.84 1.86 1.07

Infant RTF milk

Infant RTF placebo

7.5

Toddler powder

0.58

9.74

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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