AOAC OMA# 2011.06 Final Action Review-OMB

1554  S zpylka et al . : J ournal of AOAC I nternational V ol . 95, N o . 6, 2012

Table 3. Data analysis of precision study Matrix

Average

SD

RSD, %

Certified level

Powdered Infant Formula (NIST 1846) Baby Food Composite (NIST 2383)

128.4

8.0 1.3

6.25 8.59

129

14.7

15

Protein Powder (NIST 3244)

545.4

55.9

10.24

540

1245 a

Multigrain ready-to-eat cereal

1264.4

71.0

5.62

Yogurt beverage

35.9

3.6

9.97

—

Soy milk

14.3

1.7

12.18

—

Onion powder

65.8

5.4

8.25

—

Black-eyed peas

252.1

28.1

11.13

—

Eggs

88.2

9.8

11.13

—

Bananas

46.0

3.8

8.29

—

Spinach

257.1

12.1

4.69

— —

Chicken liver

1755.8

243.8

13.89

a  Average result of internal reference material analyzed by microbiological method.

the performance was demonstrated to be at constant CV through the range tested with the CV estimation being 9.9% RSD.

The relationship between variation and analyte level was established by plotting the SD as a function of the average of each sample studied. The intercept was obtained by using weighted least squares regression (weight = 1/average). This intercept estimation was determined not to be significantly different from zero ( P <0.05) with a slope of 0.099. From this,

Reference

 (1) Sullivan, D. (2012) J. AOAC Int. 95 , 287–290. http://dx.doi. org/10.5740/jaoacint.Sullivan_Intro