A novel GO based nanocomposite for electrochemical determination of folic acid (vitamin B9) in corn, rice and wheat samples

Accurate determination of folic acid (FA) levels in food sources is essential for nutritional assessment and quality control. In this work, magnetically graphene oxide/iron oxide (GO/γ-Fe₂O₃) nanocomposite was prepared via a simple precipitation method, characterized with different characterization tools (including X-ray diffraction, Fourier-transform infrared spectroscopy, vibrating sample magnetometer, transmission electron microscopy and scanning electron microscopy) and then used for fabrication of FA sensor. The electrochemical sensing potential of the GO/γ-Fe₂O₃ composite towards FA was achieved by modifying a portable screen-printed carbon electrode. Cyclic voltammetry was employed to study the experimental factors, including pH, scan rate, and the concentration of the modifier. The optimized values were then employed for quantitative determination of FA with square wave voltammetry (SWV). The results demonstrated a clear linear relationship between the SWV response and the concentration of FA, ranging from 0.04 to 70 µM. The limit of detection achieved in this study was 8 nM, which is consistent with the values reported in recent literature. The selectivity of the suggested assay was also investigated for common interference species. This research illustrates a simple, accurate, and rapid sensing platform for the quantification of FA in food samples, highlighting its potential for practical applications.