In this work, blue fluorescent silicon nanoparticles (SiNPs) were prepared by a simple one-step hydrothermal method using (3-aminopropyl) triethoxy silane (APTES) and eriochrome black T as raw materials. The SiNPs showed favorable water solubility, thermal stability, pH stability, salt tolerance, and photobleaching resistance. At an excitation wavelength of 376 nm, the SiNPs emitted bright blue fluorescence at 460 nm. In the presence of vitamin B2 (VB2), the fluorescence intensity (FL intensity) of the SiNPs at 460 nm decreased obviously, and a new peak appeared at 521 nm. Based on this, a novel ratiometric fluorescence method was established for VB2 detection. There was a good linear relationship between the fluorescence intensity ratio (F521/F460) and VB2 concentration from 0.5 to 60 μM with a detection limit of 135 nM. This method was successfully applied to detect VB2 content in the samples of vitamin B2 drugs and beverages. Additionally, a simple paper sensor based on the SiNPs was designed to visualize detection of VB2. With the support of color recognition software on a smartphone, the visual quantitative analysis of VB2 was realized, ranging from 40 to 800 μM.

Facial synthesis of nitrogen-doped graphene quantum dots and their application in the “on–off” fluorescent detection of Cr(vi) and folic acid.

A novel ratiometric fluorescence method based on a SiNPs/OPD/MnO₂ probe was developed for sensitive detection of vitamin C.