Selective and sensitive determination of Folic acid amidst interfering metal ions and biomolecules using N- doped carbon quantum dots (N-CQDs)

Abstract

Folic acid (FA), is an essential mineral required to form healthy cells and red blood cells. Inadequate FA can lead to kidney, liver and heart diseases. Therefore, developing sensitive sensors for the trace detection of FA is vital. In this study, we prepared nitrogen-doped carbon quantum dots (N-CQDs) hydrothermally using citric acid and Urea as the respective carbon and nitrogen source. The as-synthesized nanosensor was characterized using Fourier-Transform Infra-red Spectroscopy (FTIR), a High-resolution transmission electron microscope (HRTEM), and ultraviolet-visible spectroscopy (UV–vis). The as-prepared nanosensors are spherical with an average particle diameter of 3.554 ± 0.755 nm and displayed blue emission at 440 nm when excited at 370 nm. FTIR affirmed the presence of hydroxyl, carboxyl, and amino functional groups. The developed material was sensitive to pH changes, with pH 6 being the optimum. Fluorometric studies showed that the presence of FA resulted in quenching the fluorescent intensity of the as-prepared nanoprobe with high selectivity amid interfering metal ions and biomolecules. A calculated detection limit of 0.39 µM was obtained. The photoluminescence quenching mechanism reveals static quenching. The as-synthesized nanoprobe can be utilized as a fast, reliable nanosensor in actual samples.