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1402
Jing
et al.
: J
ournal of
AOAC I
nternational
Vol. 98, No. 5, 2015
Table 6. Total Choline (as ion, mg/100g as RTF) method comparison
6 days
×
2
2 days
×
2
3 days
×
2
Product name
2014.04
RSD, %
2012.20
IC
a
IC RSD, % AOAC
999.14
Abbott IMER
b
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
2.1
20.1
2.5
18.0
21.0
Adult RTF high protein
47.2
1.5
46.6
2.4
44.8
46.1
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Abbott Nutrition unpublished method employing digestion at 90°C for 3 h, immobilized enzyme reactor (IMER) column using choline oxidase to con-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.
Table 5. LOQ verification in SPIFAN sample 11750017V3 for carnitine at the SMPR limit of 0.16 mg/100 g RTF
Sample name
Concn (OH-), mg/kg Measured spike
a
, mg/kg
Theoretical spike,
mg/kg
Recovery, %
Spike level,
mg/100 g RTF
Adult powder-1
0
Adult powder-2
0
Adult powder-3
0
Adult powder-4
1.1
Adult powder-5
0
Adult powder-6
1.3
Adult powder-7
0
Unspiked
0
RSD, %
NA
b
Adult powder-LOQ-1
15.22
15.22
14.33
106.2
0.169
Adult powder-LOQ-2
14.95
14.95
14.31
104.5
0.166
Adult powder-LOQ-3
14.90
14.90
14.14
105.4
0.166
Adult powder-LOQ-4
15.30
15.30
14.37
106.4
0.170
Adult powder-LOQ-5
15.00
15.00
14.48
103.6
0.167
Adult powder-LOQ-6
15.48
15.48
14.34
108.0
0.172
Adult powder-LOQ-7
15.36
15.36
14.34
107.1
0.171
Spiked
15.17
105.9
RSD, %
1.5
1.4
a
The mean unspiked value is subtracted from the individual spiked result.
b
NA = Not applicable.
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