Rapid method for the determination of folic acid in wheat flour using high-performance liquid chromatography with diode array detection
Prado, Guilherme C.; Matos, Fábio S. de; Zanella, Renato
Palavras-chave: folic acid, vitamin B9, wheat flour, HPLC.
Resumo: In order to minimize problems related to deficient intake of the folate class of vitamins wheat flour has been enriched with folic acid (vitamin B9). Thus, it is of great importance the establishment of analytical methods for the quality control of this food. In this work a fast method using high-performance liquid chromatography with diode array detection (HPLC-DAD) was developed and validated for the determination of folic acid in wheat flour. Folic acid was extracted from the matrix with aqueous solutions of potassium hydroxide and of sodium tetraborate adjusted at pH 8.5. A clean-up step using solid phase extraction with a strong anion exchanger (SAX) as sorbent was used. HPLC using C8 column and a mobile phase consisting of water:acetonitrile at pH 2.8, in the gradient mode, was used for separation of the analyte that was detected at 285 nm. The proposed method was efficient, with good accuracy (recovery between 96 and 99%) and precision (RSD <3.8%). The method limits of detection and quantification were 0.3 and 0.9 mg kg-1, respectively. The analysis of real samples indicated that most have folic acid level below the concentration required by the Brazilian legislation.
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