197 / 363
500
] [
] [
MWS
MWS
WSx
Vit
Vol
Vit
×
=
Where,
[Vit]
WSx
:
Vitamin concentration in the working standard in ng/mL.
[Vit]
MWS
:
Concentration of vitamin in the Mixed Working Standard in ng/mL.
Vol
MWS
:
Volume of the Mixed Working Standard fortified in working standard in μL.
500:
This value is the dilution factor.
4.
Vitamin concentration calculated in product from analytical result:
PW SW
RW Vit
Vit
AS
sample
×
× ×
=
500
] [
] [
Where,
[Vit]
sample
:
Vitamin concentration in product, μg/kg
[Vit]
AS
:
Vitamin mass in the analytical sample as calculated from calibration curve,
ng/mL.
RW:
Reconstitution weight (total), g. For direct weight (liquid) samples RW = 1.
SW:
Analytical sample weight, g.
PW:
Powder weight (for reconstituted samples), g. For liquid samples, this value is 1.
500:
This value is the dilution factor.
5.
For vitamins B
3
and B
6
, the reported concentration of the individual forms is summed to report
total. For example, concentration of nicotinamide and nicotinic acid are summed to report
“Total B
3
” and concentration of pyridoxal, pyridoxamine, and pyridoxine are summed to report
“Total B
6
.” Thiamine and Riboflavin don’t require this step.
References
AOAC SMPR 2015.002 (2015)
J. AOAC Int.
98, 1094
AOAC SMPR 2015.003 (2015)
J. AOAC Int.
98, 1096
AOAC SMPR 2015.004 (2015)
J. AOAC Int.
98, 1098
AOAC SMPR 2015.005 (2015)
J. AOAC Int.
98, 1100
J. AOAC Int
. (future issue)
Posted: December 16, 2015
Candidates for 2016 Method of the Year
196