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

stability but that required to use 90% methanol instead of 20% methanol. This experiment was performed to make sure higher methanol does not affect the analytical response of the analytes . It has established earlier that injections of analytes in 90% methanol provides a satisfactory chromatography. The response of analytes at 5 ppb and 500 ppb level was investigated with injection solvent low in methanol (20%) and high in methanol (90%). The results are presented in Table 10. It can be seen that higher methanol level provided a superior response in most cases or equivalent response. Thus the standard solutions and extract for the analysis can be prepared in solutions containing 90% methanol without any loss in the analytical response. Table 16 : Comparison of response (peak area) of folate compound at two different concentrations in different injection solvents differing in %MeOH

Injection Solvent*

Std Conc ng/mL

5-CH3- THF

STD

FA

5-CHO-THF

THF

10-CH3-F

10:90:1, Formic, MeOH, Ascorbic (v/v/Wt.) 80:20, 1%Acetic,MeOH, Ascorbic (v/v/Wt.) 10:90:1, Formic, MeOH, Ascorbic (v/v/Wt.) 80:20, 1%Acetic,MeOH, Ascorbic (v/v/Wt.)

5

90% MeOH

2.91E+03

9.28E+03

6.75E+03

2.19E+03

5.18E+03

5

20% MeOH

2.18E+03

5.97E+03

5.77E+03

2.34E+03

2.45E+03

500

90% MeOH

3.34E+05

9.77E+05

7.09E+05

3.62E+05

5.54E+05

500

20% MeOH

1.78E+05

7.56E+05

5.98E+05

2.94E+05

3.06E+05

*Injection Solvents: with 90% methanol is similar to the elution solvent of SPE; with 20% methanol some what similar to the mobile phase

Evaluation of Solvent Blanks: The solvent blank (methanol) did not provide any interference in the analysis of the targeted analytes (Figure 5).

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