Separation of small inorganic anions using methacrylate-based anion-exchange monolithic column prepared by low temperature UV photo-polymerization

A methacrylate-based anion-exchange monolithic column was prepared by a single-step UV photo-copolymerization of [2-(methacryloyloxy)ethyl]-trimethyl ammonium chloride, butylmethacrylate, and ethylene dimethacrylate at a low temperature of −15 °C. The anion-exchange column exhibited good separation efficiency for the small inorganic anions of NO2−, Br−, NO3−, and I− in the isocratic mode. Under the conditions optimized using a mobile phase of 50% ACN containing 100 mM of NaCl, the theoretical plate heights of the anions were within the range of 12.2–15.6 μm (N, 64,000–82,000 m−1; k, 0.2–1.6); and a value of 9.4 μm (N, 110,000 m−1) was achieved for t0. The flow resistance of the column was acceptably low with a permeability of 2.7 × 10−13 m2. Fast gradient elution at a flow rate of 32 mm/s resulted in rapid and precise separation of the inorganic anions of IO3−, NO2−, Br−, NO3−, and I− within 20 s.