AOAC OMA# 2011.06 Final Action Review-OMB

2011.06 (September 2017)-Fol-22 MLT Report

FOR ERP USE ONLY DO NOT DISTRIBUTE

Ca-salt form of folate compounds and their respective salt free forms. j. All folate stock standard solutions may be stored at -20°C or lower temperature. These std. stock solutions may have a longer stability if stored at lower temperature like -80 o C.

Table 4-A: Preparation of Stock standards solns. of different folate compounds

Standard

Final Vol* (mL)

Folate compd #

Mass (mg)

Concen (µg/mL)

Neat standard powders available from Shircks (6S)-5-Formyl-5,6,7,8- tetrahydrofolic acid (Calcium salt) S(6R,S)-5-methyl-5,6,7,8- tetrahydrofolic acid (Calcium salt)

25

1

50

500

25

500

2

50

3

Folic acid

25

50

500

4**

pteroyltri-y-L-glutamic acid

5

10

500

* make up volume with folate stock solution solvent. **used only for checking conjugase activity in rat plasma

5.) Folate Intermediate Standard Solution (20ug/mL): a.) Add approximately 5mL of Folate Intermediate Solvent into a 10 mL volumetric flask b.) Pipette 400 µL of folic acid, formyl-THF as well as CH3-THF stock standard solutions (as specified in Table 4-B) in a 10 mL volumetric flask. Make up volume to 10 mL with the Folate Intermediate solvent. Mix contents in flask by gentle swirl. The concentration of each of the folate compound is about 20 µg/mL, (see examples in Table 4-B). c.) Sonicate in water bath for about 30 seconds. Mix the contents thoroughly by 5x inversion of the flask. d.) Store at approximately -20 o C.

Collaborative Study Report: Method AOAC 2011.06 (Folate by LC-MS/MS) 29