Amorphous colloidal photonic crystals assembled by mesoporous silica particles for thin layer chromatography with high separation efficiency and colorimetric recognition

Abstract

Amorphous photonic crystals (APCs) assembled by mesoporous SiO₂ particles were first used to develop thin layer chromatography (TLC) with high separation efficiency and convenient colorimetric recognition. The m-SiO₂ APC film has a large number of micron-scale pores, which significantly accelerate the solvent diffusion and address the problem of the short-distance development. Meanwhile, the abundant mesopores in m-SiO₂ particles intensify the adsorption–desorption between analytes and APC film. Although the critical micron-scale pores were introduced by the sacrifice of long-range ordered structure, the APC film still has uniform structural colors due to its short-range ordered structure. Therefore, the APC film retains the advantage of colorimetric recognition, where the loaded chemicals cause an increased refractive index and a structural-color change. Compared to traditional SiO₂ gel TLC, the sample recognition in APC TLC was simplified because chemical compounds, which must be dyed, can be directly recognized now. Meanwhile, the separation resolution achieved by m-SiO₂ APC TLC was also improved due to the enhancement of adsorption–desorption.