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Analysis of Vitamin D
2
and Vitamin D
3
by LC-MS/MS in Milk
Powders, Infant Formulas, and Adult Nutritionals
Page 10 of 10
PA
SILD3
= peak area of SIL d6-vitamin D
3
in sample (
units
: none)
SILIS
conc
= concentration of SIL d6-vitamin D
3
in
SILIS
(
units
: ng mL
-1
)
L = slope of calibration curve (
units
: none)
SILIS
alqt
= volume of
SILIS
aliquot spiked to sample (
units
: mL); [0.5 mL]
1000 = mass conversion factor (
units
: μg g
-1
to mg g
-1
)
100 = mass conversion factor (
units
: mg g
-1
to mg hg
-1
)
S
mass
= mass of sample (
units
: g)
The concentration of vitamin D
2
or D
3
as IU hg
-1
in the sample is calculated as:
40x ) hgg(
Result
) hg (IU
Result
-1
-1
P
where:
40 = dietary conversion factor (
units
: μg hg
-1
to IU hg
-1
)
Report:
Report result as μg hg
-1
to 1 decimal place or IU hg
-1
to 0 decimal places.
VitD-18 (February 2016)
FOR ERP USE ONLY
DO NOT DISTRIBUTE