Application of neutral hydrophobic hypercrosslinked polystyrene to the separation of inorganic anlons by ion chromatography

Neutral hydrophobic hypercrosslinked polystyrene was shown to exhibit anion -exchange properties in the pH range 2.6-4.3 that can be attributed to the presence of protonated carbonyls in the framework of the polymer. This resi n does not contain any other heteroatoms, except oxygen, responsible for th e occurrence of positive charge at the surface. The anion-exchange selectiv ity of MN-200 and monosized spherical hypercrosslinked polystyrene to inorg anic anions with diluted perchloric, nitric and sulfuric acid solutions as eluent was studied and the selectivity was found to be different from that observed for the common anion-exchangers. The main features of hypercrossli nked polystyrene are weak retention of sulphate and comparatively strong re tention of nitrite that can be useful in practical ion chromatography. The influence of column temperature on the retention was investigated. Calculat ed adsorption heats are in the range from -2 to 19 kJ/mol. The retention me chanism of inorganic anions on neutral hypercrosslinked polystyrene include s both ion-exchange and hydrophobic interactions. (C) 2000 Elsevier Science B.V. All rights reserved.