AOAC SPIFAN Nutrients ERP-Final Review (Oct. 2018)

2011.06 (September 2017)-Fol-22 MLT Report

FOR ERP USE ONLY DO NOT DISTRIBUTE

Table 4-B: Preparation of a single Intermediate standard solution of folates

Concent of folate compd in mixture (µg/mL)

Stock std. soln. Volume (µL)

Stock std. soln. Concn (µg/mL)

Final Volume * (mL)

Folate compd #

Stock Standard

(6S)-5-Formyl-5,6,7,8- tetrahydrofolic acid (6R,S)-5-methyl-5,6,7,8- tetrahydrofolic acid

1

500

400

20

10

500

400

20

2

3

Folic acid

500

400

20

*Make up final volume to 10 mL with Folate Intermediate solvent. III - Preparation of Folate Internal standard solutions

6.) Folate Internal std. Stock Solutions (1mg/mL of each internal

std. folate)

a. 13 C 5

-Folic Acid Internal Standard Stock soln.

13 C 5 -Folic Acid supplied by IsoSciences, USA (1mg/mL solution):

•

The chemical is (usually) supplied in 1 mg amount. The entire 1 mg amount of labeled folic acid is dissolved in 1 mL of the folate stock solvent. Folic acid is difficult to dissolve. Addition of 10 μL of ammonium hydroxide solution (28-30%) aids in dissolution of folic acid. Dissolve the chemical completely. Sonication and vortex for as much as 3 minutes may be necessary. The solution is stored at - 20°C. b. 13 C 5 -(6S)-5-Methyl-5,6,7,8-Tetrahydrofolate Internal Standard Stock soln. • 13 C 5 -(6S)-5-Methyl-5,6,7,8-Tetrahydrofolate supplied by IsoSciences, USA (1mg/mL solution): The labeled methyl-THF, 13 C 5 -(6S)-5-Methyl-5,6,7,8-Tetrahydrofolate (IsoSciences). The chemical is usually bought in 1 mg amount. Entire 1 mg amount of labeled methyl-THF is dissolved in 1 mL of folate stock solvent. Dissolve the chemical completely with the aid of vortex

Collaborative Study Report: Method AOAC 2011.06 (Folate by LC-MS/MS) 30