AOAC OMA# 2011.06 Final Action Review-OMB

S zpylka et al .: J ournal of AOAC I nternational V ol . 95, N o . 6, 2012  1553

samples were spiked with folic acid at four levels each. The recovery percentages were calculated by using the slope of the regression lines compared to equivalent spikes. See Table 1 for the results of the spiking recovery study.

Table 1. Spiking recovery study results

No. spike levels

Recovery, %

R 2

Sample

Infant Formula (NIST 1846) Multigrain Cereal (RM20D)

4 4 4

0.99861 101.34 0.99293 95.77 0.97393 94.10

Precision

Protein Powder (contains ephedra) (NIST 3244)

An estimation of the precision was obtained by replicate analyses. The design of this testing included 12 different matrix samples run in triplicate over a 5 day span by one analyst. The results and the data analysis can be found in Tables 2 and 3, respectively.

Yogurt drink

4

0.99476 99.39

Table 2. Results from precision study

μg total folate/100g sample

Matrix

Day 1

Day 2

Day 3

Day 4

Day 5

NIST 1846 Infant Formula

139.62 142.17 127.37

129.19 125.36 134.03

121.02 124.32 131.99

129.14 116.71 132.26

125.40 112.29 134.51

NIST 2383 Baby Food Composite

14.82 15.41 15.08

13.95 15.83 16.94

13.96 13.74 12.15

15.82 14.80 14.58

12.88 16.05 14.10

NIST 3244 Protein Powder

495.22 514.91 512.16 1177.32 1212.65 1220.70

629.77 460.78 455.24 1284.04 1249.90 1223.99

527.19 528.61 508.25 1340.69 1270.90 1328.53

602.90 608.40 613.22 1303.88 1383.12 1242.78

587.82 571.07 565.26 1317.97 1104.39 1305.04

RM20D Multigrain Cereal

Yogurt beverage

36.63 31.34 32.95 15.01 13.98 14.85 71.53 70.03 76.86

30.00 37.41 32.54 15.63 11.24 11.50 64.47 67.18 70.19

38.45 36.18 37.90 16.17 16.33 15.56 65.73 68.53 57.19

39.62 38.54 42.23 13.24 14.54 15.94 64.46 62.96 62.25

37.45 30.73 35.91 15.14 11.74 12.89 68.43 60.98 56.71

Soy milk

Onion powder

Black-eyed peas

164.00 250.10 258.73

262.59 260.90 273.16

256.38 286.41 255.55

257.55 276.17 239.75

249.37 229.25 261.21

Eggs

89.45

83.28 73.05 72.12 39.38 44.38 46.35

94.73 99.54 88.29 53.45 48.07 50.35

82.82 96.20 93.89 48.39 49.27 43.68

95.99 80.77 74.73 42.72 43.27 43.34

101.61

95.96 41.76 49.68 46.14

Banana

Spinach

252.23 253.53 286.45 1573.61 1406.58 1406.58

268.99 266.90 242.69 1649.07 1620.79 1739.81

263.08 261.75 263.56 2140.31 2145.45 1868.55

256.68 241.34 242.15 1659.20 1849.02 1961.87

252.17 247.36 257.65 1699.81 2076.24 1539.78

Chicken liver