AOAC OMA# 2011.14 (Final Action Review)-OMB

2011.14 (MTE-01) MLT FOR ERP USE ONLY DO NOT DISTRIBUTE

P oitevin : J ournal of AOAC I nternational V ol . 95, N o . 1, 2012  179

Table 2011.14A. Interlaboratory study results for calcium Matrix Mean, mg/kg Rec., % S r , mg/kg a RSD r , % b S R

, mg/kg c RSD R

, % d HorRat No. of labs e Outlier labs f

NS g

Chocolate milk powder Dietetic milk powder 2

9732.17 5678.58

99 152.10 1.56 264.03 98 75.93 1.34 184.11

2.71 3.24 4.21 6.88

0.68 0.74 0.97 1.06

9 9 9 9

NS NS NS

Infant cereal

5983.54 100 210.58 3.52 251.67

409.90 (411) h

Peanut butter NIST SRM 2387 Wheat gluten NIST RM 8418

100 13.37 3.26

28.20

367.56 (369) h

100

3.51

0.95

12.90

3.51

0.53

7

2, 4 C

a  S r

= SD for repeatability (within laboratory).

b RSD r

= RSD for repeatability.

c  S R

= SD for reproducibility (among laboratories).

d  RSD R = RSD for reproducibility. e Reporting laboratories minus outliers.

f C = Cochran outlier. g  NS = Not significant. h  Certified or reference values.

200°C for 25 min. Note: Yellow vapors will be emitted during the hydrolysis in MDO vessels. Carefully remove the MDO vessels, and allow them to cool to room temperature. Add 5 mL HCl 35% (w/v) into MDO vessels and heat at 200 ± 20°C for 20 min. Cool vessels to room temperature before venting (MDC vessels). Transfer the MDC digests to 50 mL (100 mL for MDO) volumetric flasks. Dilute to volume with H 2 O, and mix. Note : A digestion is judged complete when clear to yellow analytical solutions are produced. Filter the digested solution using an ashless filter paper for turbid samples containing fat. Discard the first 20 mL of filtrate

when using glassware and preparing standards or samples with acid solutions. Follow manufacturer’s directions for safety risk and safety environment of microwave systems. Never remove hot vessels from microwave; wait until they are near room temperature. Keep microwave door closed while vessels are hot. The door is the primary safety device if a vessel vents. ( 1 )  Sample digestion .—With power setting appropriate to MDC (maximum power of 1600 W) and MDO models (maximum power of 600 W), and number of vessels used, heat MDO vessels at 200 ± 20°C for 20 min or ramp MDC temperature from ambient to 200 ± 20°C in 15 min and hold at

Table 2011.14B. Interlaboratory study results for copper Matrix Mean, mg/kg Rec., % S r , mg/kg a RSD r , % b S R

, mg/kg c RSD R

, % d

No. of labs e Outlier labs

HorRat

NA f 101

NS g

Chocolate milk powder Dietetic milk powder 2

5.92 6.19 2.01

0.09 1.57 0.19 3.06

0.29 0.38 0.24 0.35

4.97 6.12

0.41 0.50 0.81 0.56

9 9 9 9

NS NS NS

Infant cereal

NA 0.10 4.98

11.72

4.98 (4.93) h

Peanut butter NIST SRM 2387 Wheat gluten NIST RM 8418

101

0.19 3.84

7.08

5.64 (5.94) h

95

0.13

2.27

0.27

4.77

0.39

9

NS

a  S r

= SD for repeatability (within laboratory).

b RSD r

= RSD for repeatability.

c  S R

= SD for reproducibility (among laboratories).

d  RSD R = RSD for reproducibility. e  Reporting laboratories minus outliers.

f  NA = Not available. g  NS = Not significant. h  Certified or reference values.