Determination of folic acid with a novel biomass sourced carbon quantum dot–mesoporous silica fluorescent probe†

Abstract

Folic acid (FA) is a crucial vitamin for human health, and imbalanced levels of folate can result in various illnesses. A new fluorescent probe called CQD–MSN, made from biomass carbon quantum dots and mesoporous silica, was developed through hydrothermal and template techniques to detect FA concentrations. By studying the fluorescence response and linear correlation of the CQD–MSN with FA, the optimal conditions were determined by adjusting the reaction time and pH level. The findings indicated that the best fluorescence quenching effect occurred when the pH was 7.4, and the reaction time was 4 min. At λ_ex = 355 nm and λ_em = 427 nm, the fluorescence emission spectra of CQD–MSN were notably reduced due to the combined effects of static quenching and internal filtering effect when FA was present. Under optimal conditions, the detection concentration for FA ranged from 0 to 100.0 μM, with a limit of 0.18 μM. Furthermore, CQD–MSN were effectively utilized to measure FA in real samples, including urine and rabbit serum, achieving spiked recoveries between 98.7% and 102.3%. These results demonstrated that CQD–MSN is a suitable tool for analysing FA in biosensing applications.