AOAC OMA# 2011.06 Final Action Review-OMB

2011.06 (September 2017)-Fol-22 MLT Report

FOR ERP USE ONLY DO NOT DISTRIBUTE

a) Take 12 mL of Solvent for SPE Elution in a scintillation vial or a 50 mL plastic centrifuge tube. Add 600 µL of ammonium hydroxide (28-30%) (Neutralized Solvent for SPE Elution). Mix. Prepare fresh before use. b) Pipette about 5 mL of neutralized solvent for SPE elution into a 10 mL low actinic volumetric flask. c) Pipette 20 µL, (conc. about 20 µg/mL of each of internal std. folate compound) of the internal intermediate standard solution into the 10 mL volumetric flask. Mix the contents by gentle swirling. d) Make up volume to 10 mL with the Neutralized Solvent for SPE Elution and sonicate in a water bath for about 30 sec. 5x inversion of the flask for a thorough mix of contents in the flask. e) Store at -20 o C. IV - Preparation of Calibration solutions: 10.) Folate Calibration Std. solutions: a) Prepare fresh before the analysis. Store at 4°C if necessary but not over 5 hours. b) Take 12 mL of Solvent for SPE Elution in a scintillation vial or a 50 mL plastic centrifuge tube. Add 600 µL of ammonium hydroxide (Neutralized Solvent for SPE Elution). Mix. Prepare fresh before use. c) The calibration standard solutions are prepared as detailed in the following table 4-C. Set up microfuge tubes labeled calibration std. A through G separately. d) Add intermediate std. solution as specified in the Table 4-C in the corresponding calibration tube A and B. Add 20 µl of the 2 ppm internal std solution in tubes A and B. Add Neutralized Elution Solvent in Tubes A and B as specified in Table 4-C. Close the tubes and mix thoroughly by brief vortex for about 20 seconds. e) Calibration standards C through G are prepared by dilutions of the Table 4- C specified calibration standards. Pipette the specified calibration std. in specified volume. Make up volume to 1 mL with the 40 ppb internal std solution as specified in Table 4-C. Close the tubes and mix thoroughly by brief vortex for about 20 seconds. f) Calculate exact concentration of each folate compound including internal std. in each calibration std.

Collaborative Study Report: Method AOAC 2011.06 (Folate by LC-MS/MS) 32