A porous graphitized carbon derived from silica@asphalt for online SPE of tetrabromobisphenol A derivatives and estrogens in water and milk

The synthesis of porous carbon materials often suffers from complex and costly processes. Hence, this work developed a facile template-oriented strategy using porous silica microspheres as the model substrate and inexpensive asphalt as the precursor. Asphalt was physically coated onto silica (SiO 2 @A) and then pyrolyzed to obtain porous graphitized carbon (SiO 2 @CA). After pyrolysis, the carbon content decreased from 18.80% to 7.31%, while the surface area increased from 107.0 to 308.0 m 2 g −1 . Meanwhile, SiO 2 @CA exhibited enhanced graphitization and a higher pore volume. Therefore, SiO 2 @CA was employed as a sorbent for online solid-phase extraction (SPE) of hydrophobic analytes. By optimizing the SiO 2 @CA amount in SPE columns, efficient extraction was achieved for analytes with different hydrophobicities. In an SPE column, 45 mg of SiO 2 @CA gave enrichment factors of 1990-3427 for estrogens, while 22.5 mg gave 2221-2962 for tetrabromobisphenol A derivatives. The online SPE-HPLC-DAD methods showed low detection limits (0.03-0.13 μg L −1 ), wide linear ranges, and acceptable recoveries (75.1-116% in water, 72.2-125.0% in milk). This work demonstrated a cost-effective template-assisted pyrolysis approach for developing porous carbon sorbents to enrich hydrophobic pollutants in food and environmental samples, with potential for broader applications.