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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