Facile preparation and potential application of water-soluble polymeric temperature/pH probes bearing fluorescein

摘要

An unsaturated monomer bearing xanthene groups and allyloxyfluorescein (Al-Flu), was synthesized from fluorescein and allyl bromide by etherification. The structure of the monomer was confirmed by IR and mass spectroscopy and ~1H-NMR, and ~(13)C-NMR spectroscopy. With azobisisobutyronitrile as a thermal initiator in tetrahydrofuran under 65-70°C, a copolymer of allyloxyfluorescein and acrylamide [poly(Al-Flu-co-AM)] was obtained and was characterized by the methods of IR spectroscopy, ultraviolet-visible spectroscopy, and differential scanning calorimetry. The experimental results show that the fluorescence spectra of water-soluble poly(Al-Flu-co-AM) was dependent on the pH and temperature in the solution. Moreover, poly(Al-Flu-co-AM) had an excellent linear response between the relative fluorescence intensity and temperature in the range 0-60°C and had a nonlinear response from pH 0.00 to 12.85 between the relative fluorescence intensity and pH. The pH and temperature sensitivities of the fluorescence could be advantageous for it as a multifunctional material to probe pH and temperature.