Dendrimer-functionalized hydrothermal nanosized carbonaceous spheres as superior anion exchangers for ion chromatographic separation.

Abstract

Polyamidamine (PAMAM) dendrimer-functionalized hydrothermal nanosized carbonaceous spheres (HNCSs) were prepared and utilized as latexes for agglomerated anion exchange chromatography (AEC) stationary phase. The high-concentration and scalable production of monodisperse HNCSs (73-98nm) was accomplished via the polyquaternium-7-assisted hydrothermal carbonization of fructose. The novel PAMAM-based quaternizations of HNCSs were designed by the amidation with PAMAM and epoxy-amine addition reaction with glycidol in aqueous solution. The mild functionalization condition leads to well-kept morphology of HNCSs, which forms one even latex layer on the sulfonated surface of polystyrene-divinylbenzene microbeads for the construction of AEC packing. Under isocratic elution, seven common inorganic anions and five organic acids were baseline separated in 9min on prepared packing with efficiencies of 54,000-79,800 plates m-1 and asymmetry factor (As) of 1.02-1.12. Theobtained separation efficiency, peak symmetry, and analysis time were superior to reported or typical commercial counterparts. The quick separation of polarizable anions in 7min and carbohydrates in 5min could also be carried out with symmetrical peaks (As: 1.00-1.18) and high efficiencies (49,700-62,100N/m). Favorable stability and reproducibility were proved by continuous flushing and injection. The constructed packings were further applied to the determination of thiosulfate and sulfate in water reducer, galacturonic acid in Angelica polysaccharide hydrolysate, and fluoride samples in 4min.