Background: Cucurbit[n]uril (CB[n], n=5, 6, 7, 8 and 10）is a type of macrocyclic compounds
formed by n glycerol units and 2n methylene. The different sizes of the cavity lead to the
different chemical characteristics of CB[n]. Therefore, it is very important to distinguish and detect
Methods: At room temperature, Rhodamine B was added to a gold nanoparticles solution. The above
mixture was respectively mixed with different concentrations of Cucurbituril[n] or β-cyclodextrin
solutions. The fluorescence spectra and ultraviolet-visible spectra of samples were determined.
Results: It was found that 1.2nM gold nanoparticles could quench the fluorescence of 1μM Rhodamine
B completely. After adding a certain amount of Cucurbituril, the fluorescence intensity of
Rhodamine B was restored. Compared with other macrocyclic compounds, such as Cucurbituril,
Cucurbituril and β-cyclodextrin, we found that this method had unique selectivity for Cucurbituril[
7]. Under the optimal conditions, the fluorescence recovery efficiency was linearly proportional
to the concentration of Cucurbituril in the range of 0.8-8 μg·mL-1. The detection limit was 0.21
Conclusion: The research established an effective and practical FRET-based detection method for
CB with RhB as a donor and the gold nanoparticles as the acceptor. The system had unique and
extensive selectivity for CB.