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Fonterra Co-operative Group
Page 11
Table 7: Limits of detection and quantitation for vitamin D
3
Vitamin D
3
Sample
Powder (μg hg
-1
)
RTF (μg hg
-1
)
Mean
0.12
0.013
Standard Deviation (SD)
0.013
0.001
3 x SD
0.039
0.004
10 x SD
0.13
0.014
Limit of Detection
0.16
0.018
Limit of Quantitation
0.25
0.028
Recovery
In a recovery study, a sample of similar composition to a routine sample is analysed in its original state and
after being spiked with a known amount of analyte (equation 7).
Recovery (%) =
p
U S
C
C C
x 100
equation 7
where:
C
S
= concentration of spiked sample
C
U
= concentration of unspiked sample
C
P
= concentration of spiked standard
Recovery was evaluated using unfortified samples within the SPIFAN kit. Each matrix was spiked at two
levels: 50% (5 μg hg
-1
≈
0.6 μg hg
-1
RTF) and 100% (10 μg hg
-1
≈
1.1 μg hg
-1
RTF) of typical infant formula
concentrations. Spike samples were analysed on three separate days. Recoveries measured for vitamin D
2
were between 97
–
101% (Tables 8
–
11) and for vitamin D
3
were between 94
–
101%, which are within the
limits set in the SMPR of 90
–
110% [2].
Table 8: Vitamin D
2
recovery of spiked samples at 100% of typical concentrations
Sample
Mean
Recovery
(RSD%)
Child Formula Powder
101 (0.3)
Infant Elemental Powder
98 (1.1)
Adult Nutritional RTF High Protein
99 (0.7)
Adult Nutritional RTF High Fat
99 (2.5)
Infant Formula RTF, Milk-Based
97 (2.3)
VitD-18 (February 2016)
FOR ERP USE ONLY
DO NOT DISTRIBUTE