118 / 129
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
Weigh 14.0
±
0.1 mg into a tarred weighing vessel. Quantitatively transfer to a 25-mL
volumetric flask with laboratory water and dilute to volume with laboratory water. Mix well
and transfer to a 50-mL amber bottle and Store refrigerated (2˚-8˚C).
Expiration: Until exhausted or evidence of contamination.
f)
Stable-Isotope Labeled Compounds – Internal Standard Stock Mixture (ISSM)
i)
Combine the stable-isotope labeled internal standard stock solutions in a 5:1:1:1:1:1 volume ratio
of Lab Water:
2
H
3
-Pyridoxal:
13
C
4
-Pyridoxine:
2
H
3
-Pyridoxamine:
13
C
3
-Thiamine Chloride:
13
C
4
,
15
N
2
-Riboflavin Stock Solution
For example, a sample set containing 18 samples and two
sets of 6 working standards, a minimum ISSM volume of approx. 1.5 mL is required. A 2.0
mL (allowing for excess) volume of ISSM is prepared by mixing 1250
m
L Lab Water with 250
m
L of
2
H
3
-Pyridoxal, 250
m
L of
13
C
4
-Pyridoxine, and 250
m
L of
2
H
3
-Pyridoxamine Labeled
Internal Standard Stock Solutions. Mix solution well prior to use.
Expiration: Prepare fresh daily.
NOTE: Prepare a sufficient volume of this mixture on each day of analysis to allow
for all sample preparations and standard solutions to be inoculated with 50
m
L from one ISSM solution.
g)
Native Compounds – Stock Standard Solutions
i)
Pyridoxine Stock Solution; Approximate Concentration: 1.2 mg/mL
Weigh approximately 15 mg (
±
0.50mg) of Pyridoxine Hydrochloride into a weighing funnel
or other appropriate weighing vessel. Quantitatively transfer to a 100-mL volumetric flask
with laboratory water. After mixing thoroughly, QS to volume with laboratory water.
Store refrigerated (2˚-8˚C).
Expiration: 3 months.
ii)
Pyridoxal Stock Solution; Approximate Concentration: 1.2 mg/mL
Weigh approximately 15 mg (
±
0.50mg) of Pyridoxal Hydrochloride 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.
34
BVIT-02
FOR ERP/WORKING GROUP USE ONLY
DO NOT DISTRIBUTE