AOACSPIFANMethods-2017Awards

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208 E llingson et al .: J ournal of AOAC I nternational V ol . 99, N o . 1, 2016 Table 3. Carnitine precision summary a Free carnitine

Total carnitine

, % RSD INT

, % Mean concn, mg/100 g RSD r

, % RSD INT

, %

Sample

Mean concn, mg/100 g RSD r

SRM 1849a b

13.4

2.0

2.2 NA 2.1 3.0 NA 3.2 4.1 2.1 3.6 3.5 f 3.9 3.8 NA NA NA NA 3.4 3.3

15.3

2.1 NA 4.4 1.6 NA 2.5 2.0 2.7 4.6 2.3 1.9 1.3 NA NA NA NA 1.9 2.7

1.8 NA 4.8 2.2 NA 2.2 2.5 4.7 5.0 2.9 1.7 1.5 NA NA NA NA 1.8

<0.05 c 0.909

NA d 1.8 1.8 NA 3.0 3.8 2.1 3.9 3.6 3.3 NA NA NA NA 2.3 2.9 2.7 e

AN powder milk protein-based IF hydrolyzed milk-based IF hydrolyzed soy-based AN powder low fat Child formula powder IF elemental powder IF powder milk-based IF powder soy-based IF RTF milk-based AN RTF high protein Child formula powder placebo IF elemental powder placebo AN RTF high protein placebo AN RTF high fat placebo IF RTF milk-based placebo AN RTF high fat

<0.05

1.21 1.04

1.05

<0.05 5.64 1.62 1.59 2.68 15.5 21.9 0.942 <0.05 <0.05 <0.05 <0.05

<0.05 5.76 1.63 1.82 2.78 15.7 22.3 0.948 <0.05 <0.05 <0.05 <0.05

2.67

2.67

Overall 3.1 a  Samples were run in triplicate across 4 days, n = 12. Deviation is footnoted due to outliers by Grubbs’ test at a 95% confidence interval, loss of

sample during preparation, or failure to prepare in triplicate. Twelve data points were still obtained for all samples. b  Free carnitine certified mass fraction mean and range of 13.6 mg/100 g and 12.2–15.0 mg/100 g, respectively. c  Results below the SMPR-required LOQ of 0.16 mg/100 g and not included in the calculations. d  NA = Not applicable. e  One day of duplicates used for calculation. f  Calculated across 5 days.

Table 4. Recovery analysis for choline a

Free choline

Total choline

50% Overspike, % 100% Overspike, %

50% Overspike, %

100% Overspike, %

Sample

IF powder soy-based AN RTF high protein

97.6

97.0 98.3 98.0 c 99.9

98.4 98.3

99.6 98.6

100.1

99.9 c , d

NA b

NA

AN RTF high fat

IF RTF milk-based placebo IF elemental powder placebo

101.7 95.9 e

98.8

96.8

99.3 e

NA

NA

a  Samples were run in duplicate over three days at each level, n = 6. b  NA = Not applicable. c  Samples were spiked at an amount that would achieve the upper range (250 mg/100 g) of the SMPR for choline. d n = 5, due to loss of sample during a day of analysis. e  Samples were spiked at an amount that would achieve the LOQ (2 mg/100 g) of the SMPR for choline.

Table 5. Recovery analysis for carnitine a

Free carnitine

Total carnitine

Sample

50% Overspike, %

100% Overspike, %

50% Overspike, % 100% Overspike, %

IF powder soy-based AN RTF high protein

99.3

100.2 103.6

98.7

99.7

102.4

101.5 101.4 101.6 b

102.7

IF RTF milk-based placebo IF elemental powder placebo

99.2

99.8 NA c

99.9

102.5 b

NA

a  Samples were run in duplicate over 3 days at each level, n = 6. b  Samples were spiked at an amount that would achieve the LOQ (0.16 mg/100 g) of the SMPR for carnitine. c  NA = Not applicable.