Dendritic mesoporous silica nanospheres@porous carbon for in-tube solid-phase microextraction to detect polycyclic aromatic hydrocarbons in tea beverages.

It is pretty necessary to detect effectively polycyclic aromatic hydrocarbons (PAHs, including naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene) in foods due to their widespread distribution, trace concentration, and harmful risk to humans beings. Herein, dendritic mesoporous silica nanospheres@porous carbon was developed for solid-phase microextraction of PAHs. Firstly, three-dimensional dendritic mesoporous silica nanospheres (DMSNs) with high surface area and large pore volume were synthesized via an oil-water biphase stratification approach, then porous carbon was further prepared by utilizing DMSNs and asphalt as the template and carbon source, respectively. A core-shell DMSNs@porous carbon material was successfully developed and characterized by Raman spectroscopy, elemental analysis, Brunauer-Emmett-Teller test, scanning electron microscopy, and transmission electron microscopy. DMSNs@porous carbon was proved to be a potential extraction material based on large surface area (442 m2 g-1), suitable pore sizes (about 45 nm), and high carbon content (17.36%). Subsequently, it was developed as an extraction coating and applied to online in-tube solid-phase microextraction of PAHs from tea beverages. Through coupling with high-performance liquid chromatography, an analytical method was established under optimal extraction conditions and desorption, low limits of detection (0.010-0.070 μg L-1), wide linear ranges in 0.033-10 μg L-1, and excellent correlation coefficients (most of the r reach 0.999) were received. The relative standard deviations (RSDs, n = 3) of intra-day test and inter-day test were obtained corresponding to the ranges of 0.1-2.5% and 1.0-4.1%. Finally, the method was used for detecting trace PAHs in different tea beverages from the market.