Controlled synthesis of hollow porous carbon spheres for enrichment and simultaneous determination of nine bisphenols from real samples

An extended one-step Stober method was utilized for the preparation of core@shell spheres, which was made up of a thin layer of resorcinol-formaldehyde (RF) and a silica core. After the carbonization and template-removal process, hollow porous carbon spheres (HPCSs) were synthesized. The structure of HPCSs was characterized by scanning/transmission electron microscopy and N-2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, energy dispersive X-ray spectrometer and Raman spectroscopy. The results showed that the silica cores were removed successfully and the HPCSs were in good sphere shape with uniform size, high surface areas as well as pores hollow framework structure. Compared with MWCNTs and 3D-graphene, HPCSs exhibited superior extraction ability for nine bisphenols (BPs). HPCSs showed extremely outstanding extraction efficiency for BPs as well as high adsorption capacity due to its hollow porous structure. It was applied as sorbent for the enrichment of nine BPs from environmental water samples and soft drinks prior to high performance liquid chromatographic (HPLC) analysis, obtaining recoveries ranged from 89.6% to 111.5% and the relative standard deviations (RSD) from 0.8% to 6.3%, and the limits of quantification (LOQs) were in the range of 0.183-1.763 mu g L-1.