Polystyrene-divinylbenzene stationary phases agglomerated with quaternized multi-walled carbon nanotubes for anion exchange chromatography

This work explores the potential of multi-walled carbon nanotubes as an agglomerated material for ion chromatography stationary phases for the separation of inorganic anions. Polyelectrolytes with quaternary ammonium groups were introduced onto the carbon nanotube surface, based on condensation polymerization of 1,4-butanediol diglycidyl ether (BDDE) and methylamine (MA). Quaternized multi-walled carbon nanotubes (Q-MWCNTs) were electrostatically adsorbed onto the surface of sulfonated polystyrene-divinylbenzene (PS-DVB) beads to generate the anion exchanger, which were confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A 100 mm × 4.0 mm i.d. column was packed with Q-MWCNTs agglomerated PS-DVB particles, with a capacity of 56 μequiv./column. Separation of inorganic anions, such as F−, Cl−, NO2−, Br−, NO3−, SO42− and PO43− were performed. The stationary phase was rigid, chemically stable and showed good ion-exchange characteristics.