A Simple and Sensitive Nanocatalytic Fluorescence Method for the Determination of Folic Acid in Foods Using Fe3O4 Nanoparticle-K2S2O8 System

In pH 2.72 HCl-NaAc buffer solution at room temperature and in the presence of a nanocatalyst of Fe3O4 nanoparticles, potassium persulfate rapidly oxidized folic acid (FA) to form a product with strong fluorescence at 446 nm. The analytical conditions were considered, and a simple, rapid, and accurate fluorescence method was proposed for the determination of 0.007-8.0 mg/L FA, with a detection limit of 2.0 ng/mL FA. This method was applied to the analysis of FA in a real sample with satisfactory results that agree with the HPLC results.