Covalent triazine-based framework for micro solid-phase extraction of parabens.

Herein, nano-sized covalent triazine-based framework grafted magnetic particles were synthesized by a facile Friedel-Crafts reaction between cyanuric chloride as node and biphenyl as linker. The formation of the material has been confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, field emission-scanning electron microscopy, thermogravimetric analysis, and N2 adsorption-desorption measurement. With respect to the material structure, the large number of aromatic rings in the molecular framework provided a bed for extracting aromatic ring-containing compounds through π-π stacking interactions. The applicability of the prepared material as a new sorbent for micro solid-phase extraction of parabens was investigated. The effect of key experimental parameters affecting the extraction efficiency of the analytes including sorbent amount, sample pH, extraction time and desorption conditions were investigated. High-performance liquid chromatography with UV detection was used for determining the enriched analytes. The method was successfully applied for determining parabens in human urine, breast milk, personal care products, and shower wastewater. After optimization, the linearity range of 0.1-500 µg L-1 and detection limit of 0.02 µg L-1 were obtained for all the selected parabens. The relative standard deviations and recoveries for the real sample analysis were in the range of 2.3-5.0% and 86-102%, respectively.