AOAC SPIFAN ERP Meeting Book-March 16, 2016

2011.06 (Fol-22) w/SLV FOR ERP USE ONLY DO NOT DISTRIBUTE

Silliker Chem, Res. Center Crete, IL – Report of A Validation of LC-MS/MS Method for Folate Analysis

XICof +MRM(14pairs): 442.200/295.200DaID: FA-295fromSample17(Solvent ) of HSST3_121130_01.wiff (TurboSpray)

Max. 60.0cps.

10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 In te n sity, cp s

0 5

4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4 7.6 7.8 2 18 33 49 64 80 96 111 127 142 158 173 189 205 220 236 251 267 283 298 Time, min

Figure 3: Chromatograms of a solvent blank (methanol).

Sodium salt vs. Free Ascorbic acid In the original AOAC method, the sodium ascorbate rather than ascorbic acid was used. It will not make any difference in the extraction buffer because the pH was adjusted to 6.0 using sodium hydroxide. However, for the SPE elution solvent and final injection solvent, the pH was not adjusted. A small test of the elution solvent made from both sodium ascorbate and ascorbic acid (formic acid/methanol/ascorbate v/v/w 10:90:1) was carried out. The SPE eluates from the two elution solvent gave the same response and made no difference for both the peak shape and intensity. Actually, the formic acid concentrations in the solvent were so high that the minimum amount of sodium cannot affect the solvent acidity, which is the most important factor for a anion exchange procedure in the SPE. The chromatograms from both of the treatments are presented in Figures 8 and 9.

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