Molecular imprinted material prepared by novel surface imprinting technique for selective adsorption of pirimicarb

In this paper, a molecular imprinted material with high performance for recognizing pirimicarb, which is a kind of carbamate pesticide, was prepared by adopting the novel surface molecular imprinting technique put forward by us previously. Firstly, the functional macromolecule poly(methacrylic acid) (PMAA) was grafted on the surface of silica gel particles in the manner of “grafting from” using 3-methacryloxypropyl trimethoxysilane (MPS) as an intermediate, and the grafted particle PMAA/SiO2 was formed. Afterwards, the molecular imprinting was carried out towards the macromolecule PMAA grafted on the surface of silica gel particles using pirimicarb as template and ethylene glycol diglycidyl ether (EGGE) as crosslinking agent via the intermolecular hydrogen bond and electrostatic interaction, and pirimicarb imprinted material MIP-PMAA/SiO2 was obtained. The combining characteristic of MIP-PMAA/SiO2 for pirimicarb was studied profoundly with static method. The experimental results show that the surface-imprinted material MIP-PEI/SiO2 has excellent combining affinity and recognition selectivity for the template molecules of pirimicarb. Before imprinting, PMAA/SiO2 has greater adsorption capacities for pirimicarb as well as for the contrast substances, atrazine and propoxur, whose structures are similar to pirimicarb, and the selectivity coefficients of PMAA/SiO2 for pirimicarb with respect to atrazine and propoxur are only 1.523 and 0.612, respectively. However, after imprinting, the combining capacities of MIP-PMAA/SiO2 towards atrazine and propoxur decrease remarkably, whereas that of MIP-PMAA/SiO2 for pirimicarb still remains higher. The coefficients of MIP-PMAA/SiO2 for pirimicarb with respect to atrazine and propoxur were enhanced greatly, and they are 12.20 and 14.15, respectively. Besides, MIP-PMAA/SiO2 adsorbing pirimicarb in a saturated state has fine elution and reuse properties.