Pressurized liquid extraction and HPLC quantification of folic acid in fortified wheat flours.

A pressurized liquid extraction (PLE) method using phosphate buffer as solvent was applied for folic acid (FA) extraction from fortified wheat flours and was compared to a standard solid liquid extraction (SLE) method. Extracted FA was quantified by reverse phase high-performance liquid chromatography (RP-HPLC) hyphenated with a phenyl column and an absorption photometric detector (lambda = 280 nm). Detection and quantification limits were 0.12 and 0.4 ng, respectively, corresponding to 0.06 and 0.2 mu g g(-1) of analyzed wheat flour. Equivalent FA contents were found by both extraction methods, but a single PLE allowed a total recovery of FA content, whereas at least three successive SLEs were needed to achieve a total recovery of FA. The obtained results indicated that PLE is a rapid and efficient technique for FA extraction from fortified wheat flour.