Conductimetric sensor for atrazine detection based on molecularly imprinted polymer membranes

Atrazine-sensitive conductimetric sensors were designed using molecularly i mprinted polymer membranes. Membranes containing artificial recognition sit es for atrazine were prepared by copolymerization of methacrylic acid and a cross-linker, tri(ethylene glycol) dimethacrylate, in the presence of atra zine as a template. in order to improve the flexibility and mechanical stab ility of the membranes, oligourethane acrylate was added to the mixture of monomers. The recognition sites complementary to atrazine were formed in th e membranes after extraction of the template molecules with ethanol. Altern atively, reference polymer membranes were prepared with the same monomers b ut without the template. The responses of the membranes prepared with and w ithout the template were monitored conductimetrically. The membranes prepar ed in the presence of atrazine showed significantly stronger responses to a trazine than to analogous compounds (triazine, simazine, prometryn). The re sponse time was 6-15 min depending on the membrane thickness. The effect of the membrane composition and the porogen concentration on the magnitude of the conductimetric responses was also investigated. With the sensor design ed here, the detection of the atrazine at concentrations down to 5 nmol dm( -3) was demonstrated. During a 6 month period, the sensitivity of the molec ularly imprinted membranes to atrazine was found to remain constant.