Silicon Nanoparticle-Based Ratiometric Fluorescence Probes for Highly Sensitive and Visual Detection of VB 2 .

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 B 2 (VB 2 ), 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 VB 2 detection. There was a good linear relationship between the fluorescence intensity ratio ( F 521 / F 460 ) and VB 2 concentration from 0.5 to 60 μM with a detection limit of 135 nM. This method was successfully applied to detect VB 2 content in the samples of vitamin B 2 drugs and beverages. Additionally, a simple paper sensor based on the SiNPs was designed to visualize detection of VB 2 . With the support of color recognition software on a smartphone, the visual quantitative analysis of VB 2 was realized, ranging from 40 to 800 μM.