CoFe2O4/GO nanocomposite as a reusable magnetic sorbent for determination trace amounts of vitamin B9 in food samples

Abstract

Vitamin B9 (folic acid) is one of the B vitamins that is naturally present in many food sources. The presence of vitamin B9 and its derivatives is necessary in important biochemical processes such as amino acid metabolism, nucleic acid synthesis and cell division. The deficiency of vitamin B9 may cause several diseases including anemia, cancer, hypertension, diabetes, psychiatric disorders, etc. Therefore, it is considered necessary to investigate and determine this vitamin, especially in food samples. In this work, magnetic cobalt ferrite/graphene oxide (CoFe2O4/GO) sorbent was synthesized and characterized by Fourier transform infrared (FT-IR) spectroscopy, vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM) and X-Ray diffraction (XRD). Magnetic dispersive micro-solid phase extraction (MD-μ-SPE) consisting of CoFe2O4/GO nanocomposite coupled with a green, precise, accurate, and robust spectrofluorometric approach was used for preconcentration, separation and determination of vitamin B9. Four parameters of pH, sorbent dose, temperature and sonication time were selected as effective variables on the process and optimized by central composite design (CCD). Under optimized conditions, the linear range, limit of detection, RSDintra-day, RSDinter-day were obtained 15-750 ng mL-1 , 3.96 ng mL-1 , 13.07 ng mL-1 , 3.35% and 4.5%, respectively. Finally, the proposed method was successfully applied for preconcentration and determination of vitamin B9 in mint, broccoli and lettuce food samples. In addition, antibacterial activity of the CoFe2O4/GO nanocomposite was evaluated on Escherichia coli and Staphylococcus aureus bacteria.