6. AOACSPIFANMethods-2018Awards

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1402  Jing et al. : J ournal of AOAC I nternational Vol. 98, No. 5, 2015

Table 5. LOQ verification in SPIFAN sample 11750017V3 for carnitine at the SMPR limit of 0.16 mg/100 g RTF

Theoretical spike, mg/kg

Spike level, mg/100 g RTF

Concn (OH-), mg/kg Measured spike a , mg/kg

Sample name

Recovery, %

Adult powder-1 Adult powder-2 Adult powder-3 Adult powder-4 Adult powder-5 Adult powder-6 Adult powder-7

0 0 0

1.1

0

1.3

0 0

Unspiked

NA b

RSD, %

15.22 14.95 14.90 15.30 15.00 15.48 15.36 15.17

15.22 14.95 14.90 15.30 15.00 15.48 15.36

14.33 14.31 14.14 14.37 14.48 14.34 14.34

106.2 104.5 105.4 106.4 103.6 108.0 107.1 105.9

0.169 0.166 0.166 0.170 0.167 0.172 0.171

Adult powder-LOQ-1 Adult powder-LOQ-2 Adult powder-LOQ-3 Adult powder-LOQ-4 Adult powder-LOQ-5 Adult powder-LOQ-6 Adult powder-LOQ-7

Spiked RSD, %

1.5

1.4

a  The mean unspiked value is subtracted from the individual spiked result. b NA = Not applicable.

Table 6. Total Choline (as ion, mg/100g as RTF) method comparison 6 days × 2

2 days × 2

3 days × 2

2012.20 IC a

Abbott IMER b

2014.04

IC RSD, % AOAC 999.14

Product name

RSD, %

SRM1849a (certified 12.1) c

11.4

1.2

10.2

1.8

11.3

10.7

Infant powder milk

16.9

1.8

15.8

2.3

14.7

16.2

Infant powder soy

19.2

2.0

17.8

2.5

18.0

19.3

Infant powder milk part hydrolyzed

17.9

1.8

17.1

2.0

14.9

17.6

Infant powder soy part hydrolyzed

17.0

1.7

16.4

2.1

13.4

17.1

Adult powder low fat

17.4

2.3

16.6

2.1

16.6

16.4

Adult powder milk

4.03

3.2

3.00

3.0

3.00

3.90

Child formula powder

5.45

2.1

4.96

2.7

4.79

5.20

Infant elemental powder

8.16

1.9

7.70

2.1

3.78

7.95

Infant RTF milk

20.9 47.2

2.1 1.5

20.1 46.6

2.5 2.4

18.0 44.8

21.0 46.1

Adult RTF high protein

Adult RTF high fat

51.5

1.3

51.1

2.5

50.9

51.9

a  Thermo Fisher Scientific ion chromatography 2012.20 SLV, 6 days in duplicate, from published Application Note (5). b  Abbott Nutrition unpublished method employing digestion at 90°C for 3 h, immobilized enzyme reactor (IMER) column using choline oxidase to con- vert choline to betaine and peroxide, followed by electrochemical detection of peroxide. c  The certified value for SRM 1849a is 1090 mg/kg as powder, or 12.1 mg/100 g RTF as total choline ion.