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Silliker
Chem, Res. Center Crete, IL – Report of A Validation of LC-MS/MS Method for Folate Analysis
7
stable for only 90 days stored in the freezer at -70
o
C.
f.)
Pteroyltri-y-glutamate (FA-glu
3
) is stable for 12 months stored in the freezer at -70
o
C.
Preparation of Stock standards of different folate compounds
Table 2: Preparation of Stock standard solns. (examples) of different folate compounds
Folate
compd
#
Standard
Mass (g)
Final
Vol*
(mL)
Concen
(mcg/mL)
1
Shircks (6S)-5-Formyl-5,6,7,8-
tetrahydrofolic acid
0.00607
10
607
2
10-Formylfolic acid
0.00597
10
597
3
Shircks (6R,S)-5-methyl-5,6,7,8-
etrahydrofolic acid
0.00584
10
584
4
10-methylfolic acid
0.00529
10
529
5
Shircks (6R,S)-5,10-methenyl-
5,6,7,8-tetrahydrofolic acid
0.00587
10
587
6**
pteroyltri-y-L-glutamic acid
0.00911
10
911
7
Shircks (6S)-5,6,7,8-tetrahydrofolic
acid
0.00542
10
542
8
Shircks Folic acid
0.00555
10
555
* make up volume to 10 mL with stock solution solvent.
**used only for checking conjugase activity in rat plasma
5). Folate Internal std.Stock solutions:
a.
13
C-Folic Acid Internal Standard Stock soln. (2000
ug/mL)
- The labeled
Folic acid,
13
C-Folic Acid Millipore / Merck CH2QC-900824. The chemical is
usually bought in 20 mg amount. The entire 20 mg amount of labeled folic
acid is dissolved in 10 mL of folate stock std. solvent. Dissolve the
chemical completely with the aid of vortex and brief (15 second) sonication.
The solution is anticipated to be stable for up to 5 months at -70
o
C.
Stability to be checked during and after this period before use.
b.
13
C5-(6S)-5-Methyl-5,6,7,8-Tetrahydrofolate Internal Standard Stock soln.
(2000
ug/mL)
: The labeled methyl-THF ,
13
C5-(6S)-5-Methyl-5,6,7,8-
Tetrahydrofolate (Millipore / Merck CH2QA-900827). The chemical is
usually bought in 20 mg amount. The entire 20 mg amount of labeled
methyl-THF is dissolved in 10 mL of folate stock std. solvent. Dissolve the
chemical completely with the aid of vortex and brief (15 second) sonication.
The solution is anticipated to be stable for up to 3 months at -70
o
C.
Stability to be checked during and after this period before use
6.
Folate Intermediate Standard Solution (20ug/mL):
2011.06 (Fol-22) w/SLV
FOR ERP USE ONLY
DO NOT DISTRIBUTE