Fabrication of Eu3+-dipicolinic acid complex functionalized nanoSiO2 composites and their Langmuir-Blodgett films as visual fluorescence probe for tetracycline and oxytetracycline

Luminescent lanthanide complexes have attracted growing attention in the visual probe for detection of toxic and dangerous materials. Here, we report an interfacial self-assembly of Eu 3+ -dipicolinic acid complex functionalized nanoSiO 2 composites (nanoSiO 2 PyTAEu) and their Langmuir-Blodgett (LB) films as well as the luminescent probes to tetracycline (TC) and oxytetracycline (OTC). Organic linkers and Eu 3+ ions are anchored on the hydrophilic nanoSiO 2 particles’ surface via the surface silanization, substitution and coordination reactions, so they exhibit high stability and well distribution in the solutions and LB films. Both the nanocomposites of nanoSiO 2 PyTAEu and their LB films show strong and enhanced red fluorescence emissions of Eu 3+ ions when they are immersed in the aqueous TC solution, with the detection limit to 3.3 and 0.91 nmol/L, respectively. The present nanocomposites and LB films have the advantages of high sensitivity and stability.