Ratiometric Detection of Rifampin by Using Self‐Assembled Nanocomposites with Dual Fluorescence Emissions and Analysis of Two‐Dimensional Correlation Spectroscopy

A new ratiometric fluorescence probe is constructed for the detection of rifampin (RIF). Amino‐modified silicon nanoparticles (SiNPs) and mercaptoundecanoic acid capped gold nanoclusters (MUA‐AuNCs) are self‐assembled into nanocomposites, showing dual fluorescence emissions, respectively, at 440 and 615 nm under a single excitation of 300 nm. The morphology, surface chemistry and optical properties of the nanocomposites are finely investigated through transmission electron microscopy (TEM), Fourier transforms infrared spectroscopy (FT‐IR), UV–vis absorbance, dynamic and steady state fluorescence spectroscopy. Owning to rich hydroxyl groups, RIF can bind with MUA‐AuNCs though hydrogen bonds resulting in the red fluorescence quenching. But the SiNPs keep their own blue fluorescence stable, which can act as an internal reference for ratiometric detection. By means of the ratio I 615 / I 440 , the linear relationship is established in the range from 0.1 to 5 μM with the detection limit of 0.04 μM. In addition, the synchronous and asynchronous fluorescence 2D correlation maps have been created to in‐depth study the relative detecting mechanism.