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

摘要

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 NO _2 ~-, Br ~-, NO _3 ~-, and I - in the isocratic mode. Under the conditions optimized using a mobile phase of 50% ACN containing 100mM of NaCl, the theoretical plate heights of the anions were within the range of 12.2-15.6μm (N, 64,000-82,000m ~(-1); k, 0.2-1.6); and a value of 9.4μm (N, 110,000m ~(-1)) was achieved for t _0. The flow resistance of the column was acceptably low with a permeability of 2.7×10 ~(-13)m ~2. Fast gradient elution at a flow rate of 32mm/s resulted in rapid and precise separation of the inorganic anions of IO _3 ~-, NO _2 ~-, Br ~-, NO _3 ~-, and I - within 20s.