Highly-Sensitive Ion Selective Electrode Based on Molecularly Imprinted Polymer Particles for Determination of Tetracycline in Aqueous Samples

In this work, a highly-sensitive polymeric membrane ion selective electrode for determination of tetracycline was constructed by using molecularly imprinted polymer (MIP) particles as quasi-ionophore. The water-compatible MIP particles targeting tetracycline were synthesized with tetracycline as a template molecule, methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, 2,2'-azobisisobutyronitrile as an initiator and lanthanum ion as a mediator. Benefited from the distinctive performance of the quasi-ionophore and the optimized composition of the membrane and the inner filling solution, the lower detection limit of the electrode was decreased to about 1 x 10 (8) mol/l. It exhibited a good electrode slope 59.8 mV/decade near the theoretical Nernstian one, with a wide linear working range from 2.0 x 10(-8) to 1.0 x 10(-3) mol/l. Due to the specific recognition of tetracycline by the MIP particles, the selectivity coefficients for routine interferences were less than 10(-4). The fabricated electrode should be used in pH 2-4, response time of which was less than 200 s when the concentration of tetracycline was higher than 1.0 x 10(-6) mol/l and no more than 30 min at the concentration of 1.0 x 10(-8) mol/l. Finally, the proposed highly-sensitive ion selective electrode has been successfully applied to the determination of tetracycline in aqueous samples.