Abbott Nutrition Division
Simultaneous Determination of Total Vitamin B
6,
B
2,
B
3
and B
1
in Infant
Formula Products by LC-MS/MS Using Enzymatic Digestion
iii)
Pyridoxamine Stock Solution; Approximate Concentration: 1.2 mg/mL
Weigh approximately 18 mg (
±
0.50mg) of Pyridoxamine dihydrochloride into a weighing
funnel or other appropriate weighing vessel. Quantitatively transfer to a 100-mL volumetric
flask with laboratory water. Mix thoroughly, then QS to volume with laboratory water.
Store refrigerated (2˚-8˚C).
Expiration: 3 months.
iv)
Riboflavin Stock Standard Solution: 30 mg/L
Dry an appropriate amount of the USP riboflavin reference standard at 105 (
±
1)
°C
for 2 hours
(
±
10 minutes) prior to making the stock standard. All work with riboflavin standards must be
conducted under yellow lighting as specified in Apparatus section. Accurately weigh 0.033000
(± 0.00010) g of the reference standard and quantitatively transfer to a 1000-mL volumetric
flask. Add approx. 800 mL water and 1.2 (
±
0.1) mL acetic acid, glacial. Mix to dissolve. Bring
to volume with water. Mix well and store under yellow lights.
Store refrigerated (2˚-8˚C).
Expiration: 3 months.
v)
Thiamine Stock Standard Solution: 100 mg/L
Determine the moisture of the USP thiamine HCL reference standard as directed on the
container just prior to making the stock standard. Using the percent moisture of the reference
standard, determine the amount of reference standard to accurately weigh out to equal
0.025000g (± 0.0010) g per 500250mL. Quantitatively transfer to a 500250-mL volumetric
flask. Add approximately 300150 mL 0.15 M HCl. Mix to dissolve and bring to volume with
0.15 M HCl. Mix well and Store under yellow lights.
Store refrigerated (2˚-8˚C).
Expiration: 3 months.
h)
Intermediate Working Standard Solution (IWSS)
Combine the following volumes of the stock standard solutions in a 10-mL volumetric flask
containing approximately 5 mL of laboratory water.
Table 4. Stock Standard solutions volumes needed to make IWSS.
Vitamin Stock Standard Solution
Volume (µL)
Pyridoxine
250
Pyridoxal
50
Pyridoxamine
50
35
BVit-02
FOR ERP USE ONLY
DO NOT DISTRIBUTE