The synthesis, spectroscopic characterization and complexing properties of calixarene-based fluorescent
sensors are reported. The calixarene bearing four dansyl fluorophores (Calix-DANS4) exhibits a very high affinity for
the detection of lead. A fluorimetric micro-device based on the use of a Y-shape microchannel was developed and
allows lead detection with a 5 ppb detection limit. For mercury detection, a fluorescent molecular sensor containing a
calixarene anchored with four 8-quinolinoloxy groups (Calix-Q) has been synthesized. The absorption and fluorescence
spectra of this sensor are sensitive to the presence of metal cations. An efficient fluorescence quenching is observed
upon mercury complexation because of a photoinduced electron transfer from the fluorophore to the bound mercury.
Calix-Q shows a high selectivity towards Hg2+ over interfering cations (Na+, K+, Ca2+, Cu2+, Zn2+, Cd2+ and Pb2+) and a
70 ppb sensitivity.
|