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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 8 of 10

1000

10

1.0 x

SS SILD

SILIS

D3conc

3

D3conc

u

where:

SILIS

D3conc

= concentration of SIL d6-vitamin D

3

in internal standard (

units

: ng mL

-1

)

SILD

3

SS

D3conc

= concentration of SIL d6-vitamin D

3

in stock standard (

units

: μg mL

-1

)

1000 = concentration conversion factor (

units

: μg mL

-1

to ng mL

-1

)

Concentration of non-labelled vitamin D

2

in purity standard

NLD

2

PS

:

10000

x

1%

1cm

max)

abs(

λ

2

D2conc

2

E

PS NLD

PS NLD

where:

NLD

2

PS

D2conc

= concentration of vitamin D

2

in purity standard (

units

: μg mL

-1

)

NLD

2

PS

abs(

λ

max)

= UV absorbance of purity standard at 265 nm (

units

: none)

= extinction coefficient for vitamin D

2

in ethanol [461] (

units

: dL g

-1

cm

-1

)

10000 = concentration conversion factor (

units

: g dL

-1

to μg mL

-1

)

Concentration of non-labelled vitamin D

3

in purity standard

NLD

3

PS

:

10000

x

1%

1cm

max)

abs(

λ

3

D3conc

3

E

PS NLD

PS NLD

where:

NLD

3

PS

D3conc

= concentration of vitamin D

3

in purity standard (

units

: μg mL

-1

)

NLD

3

PS

abs(

λ

max)

= UV absorbance of purity standard at 265 nm (

units

: none)

= extinction coefficient for vitamin D

3

in ethanol [485] (

units

: dL g

-1

cm

-1

)

10000 = concentration conversion factor (

units

: g dL

-1

to μg mL

-1

)

Concentration of non-labelled vitamin D

2

in working standard

NLWS

:

1000

10

1.0 x

PS NLD

NLWS

D2conc

2

D2conc

u

where:

NLWS

D2conc

= concentration of vitamin D

2

in working standard (

units

: ng mL

-1

)

NLD

2

PS

D2conc

= concentration of vitamin D

2

in purity standard (

units

: μg mL

-1

)

1000 = concentration conversion factor (

units

: μg mL

-1

to ng mL

-1

)

Concentration of non-labelled vitamin D

3

in working standard

NLWS

:

1000

10

1.0 x

PS NLD

NLWS

D3conc

3

D3conc

u

where:

NLWS

D3conc

= concentration of vitamin D

3

in working standard (

units

: ng mL

-1

)

NLD

3

PS

D3conc

= concentration of vitamin D

3

in purity standard (

units

: μg mL

-1

)

1000 = concentration conversion factor (

units

: μg mL

-1

to ng mL

-1

)

Concentration of vitamin D

2

and vitamin D

3

in calibration standards

CS1–5

:

25

0.01 x

NLWS

CS1

D2conc

D2conc

25

0.01 x

NLWS

CS1

D3conc

D3conc

25

0.05 x

NLWS

CS2

D2conc

D2conc

25

0.05 x

NLWS

CS2

D3conc

D3conc

1%

1cm

E

1%

1cm

E

VitD-18 (February 2016)

FOR ERP USE ONLY

DO NOT DISTRIBUTE