Design and preparation of magnetic mesoporous melamine-formaldehyde resin: A novel material for pre-concentration and determination of silver

Using commercially available melamine and formaldehyde as the starting materials, a magnetic mesoporous melamine-formaldehyde resin (MMF@Fe3O4) possessing large surface area was prepared via a simple method and could be used as an efficient adsorbent for magnetic solid-phase extraction. Compared with the traditional synthetic methods of MMF@Fe3O4, this approach is easily operated under mild conditions, is time-saving and environmentally friendly, and can produce the material in high yields. The as-prepared MMF@Fe3O4 possesses good adsorption capacity and selectivity for silver ions. The affecting factors such as pH, amount of MMF@Fe3O4, extraction time, desorption solvent, eluent concentration and sample volume were systematically investigated and optimized. Under the optimized conditions, the material exhibited a good response to silver ions at concentrations in the range 2.0-200 mu g l(-1) with good linearity (r(2) = 0.9982), while the limit of detection was found to be 0.12 mu g l(-1). The material was successfully applied to the determination of silver in a variety of water samples.