Sustainable hydrophilic ultrasmall carbonaceous spheres modified by click reaction for high-performance polymeric ion chromatographic stationary phase

Novel poly(ethylvinylbenzene-divinylbenzene) (EVB-DVB) agglomerated with ultrasmall carbonaceous spheres (UCSs) anion-exchange packings for ion chromatography (IC) were constructed. Hydrophilic UCSs with mean sizes of 62-98 nm were synthesized in quantity by the polydiallyl dimethyl ammonium chloride aided hydrothermal carbonization of fructose. The green strategy based on the thiol-ene click reaction with cysteamine in aqueous system was first designed for the hyperbranched polyquaternary amine (HPA) grafting of UCSs with negligible damage on their monodispersity. The HPA modified UCSs were evenly distributed on sulfonated EVB-DVB substrate to form one uniform layer of functional nanospheres without observable coagulum. Seven typical anions (F^-, Cl^-, NO₂^-, Br^-, NO₃^-, SO₄^2- and PO₄^3-) were baseline separated on constructed packing in 5 min with high efficiencies in the range of 44,800-71,100 plates m ^- 1. The rapid separation of polarizable anions, small organic acids and saccharides could be also accomplished under isocratic elution with competitive peak symmetry and efficiency. Good reproducibility was demonstrated by consecutive injection. Thiosulfate in water reducer was further detected on prepared packing in 4 min with detection limit of 0.04 mg L ^- 1 (S/N = 3) and good repeatability.