AOAC OMA# 2011.14 (Final Action Review)-OMB

Table 2011.14H. Interlaboratory study results for phosphorus Matrix Mean, mg/kg Rec., % S r a

RSD r

b , % S

R c , ng/g RSD R

d , % HorRat

No. of labs e Outlier labs f

Chocolate milk powder Dietetic milk powder 2

4138.12 3729.50 4341.81

101 84.53 100 46.37 101 60.56 102 98.10

2.04 1.24 1.39 2.85

115.22 101.72 111.79 111.97

2.78 2.73 2.57 3.25

0.61 0.59 0.57 0.69

9 9 9 9

NS g

NS NS NS

Infant cereal

Peanut butter NIST SRM 2387 3444.06 (3378) h

Wheat gluten NIST RM 8418

2050.02 (2190) h

94

37.86

1.85

67.15

3.28

0.65

9

NS

salted food raw materials (e.g., culinary products or tastemakers) and a minimum of 500 mg/kg cesium (for main food samples); 20 mg/kg indium and 5 mg/kg strontium, yttrium, and chromium; less than half of each element concentration of the higher working standard Std6 and less than 0.5 g/kg total dissolved minerals. Power settings and nebulizer gas flowmust be optimized to ensure that the Mg280.271:Mg285.213 ratio (Mermet principle of robust plasma) demonstrates robust operating conditions in accordance with the ratio established by the instrument manufacturer. At least three replicate readings of the same sample are performed, with relatively long integration times to minimize noise. ( b ) ICP wavelengths . ____ A number of recommended and alternative wavelengths may be used for the nine elements to be determined and internal standards. As a minimum, select one recommended and one alternative wavelength for each element 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.

corrected by one recommended wavelength for appropriate internal standard. All responses for both recommended and alternative wavelengths for each element are corrected using only one internal standard line. The following is a list of wavelengths for each element (and its appropriate internal standard) in priority order that have been found acceptable for main foodstuffs: Wavelength (nm): Ca: 317.933 (In: 303.936); Cu: 324.754 (In: 303.936); Fe: 259.94 (Sr: 338.071); K: 766.491 (Sr: 460.733); Mg: 285.213 (In: 303.936); Mn: 257.610 (Sr: 338.071); Na: 589.592 (Sr: 460.733); P: 213.618 (In: 303.936); Zn: 213.857 (Sr: 338.071). Other wavelengths that are acceptable for both elements and internal standards could be used as confirmatory analytical lines or alternative wavelengths as certain recommended lines may not be available on some ICP-OES systems: Wavelength (nm): Ca: 317.933 (Y: 371.028); Cu: 324.754 (Y: 371.028), 327.395 (In:

Table 2011.14I. Interlaboratory study results for zinc Matrix Mean, mg/kg Rec., % S r a

RSD r

b , % S

R c , ng/g RSD R

d , % HorRat

No. of labs e Outlier labs f

Chocolate milk powder Dietetic milk powder 2

18.06 53.65 36.51

NA h 105

0.396

2.19 2.66 2.25 3.96

0.95 2.36 1.27 1.78

5.24 4.40 3.44 6.69

0.51 0.50 0.37 0.69

8 9 9 9

5SG

1.43

NS NS NS

Infant cereal

NA 0.92

Peanut butter NIST SRM 2387 26.64 (26.3) i

101

1.06

Wheat gluten NIST RM 8418

49.30 (53.8) i

92

0.96

1.95

3.19

6.46

0.73

9

NS

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.

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