Modification of hollow microporous organic network with polyethyleneimine for efficient enrichment of phenolic acids from fruit juice samples

Owning to the hydrophobic characteristics of microporous organic networks (MONs), their utilizations still largely limited in non- and weak-polar analytes. To expend their applications, here we reported the synthesis of a novel hollowed H-MON-PEI₁₈₀₀–2 composite via sacrifice template method and subsequent modification with polyethyleneimine (PEI) for efficient solid phase extraction of polar and ionic phenolic acid (PAs) from fruit juice samples. H-MON-PEI₁₈₀₀–2 exhibits large surface area, rapid extraction kinetics, remarkable chemical and thermal stabilities, and provides synergistic electrostatic, π-π, hydrogen bonding, and hydrophobic interaction sites for PAs. The developed method owns low limit of detection, wide linear range, large enrichment factors, and good reusability. The recoveries of H-MON-PEI₁₈₀₀–2 for PAs are 1–3 orders of magnitude higher than those of commercial adsorbents like activated carbon, C18 and Oasis HLB. This work highlights the prospects of functional H-MONs for enriching polar and ionic targets from complex sample matrices.