| Recently, the substrates which can induce room temperature phosphorescence(RTP) of phosphor attract more and more attention. Supramolecular gels formed by non-covalent interaction with unique structures and properties, such as ordered 3D network structure, controlled morphology and stimulative response, is expected to be a potential new substrate to induce RTP.In this paper, firstly, it was found that the supramolecular gels formed by 1,3(R):2,4(S)-di-O-benz ylidene-D-sorbitol(DBS) can induce strong RTP of 3-bromoquinoline(3-Br Q). Secondly, the temperature-response of 3-Br Q/DBS and the mechanism of induction RTP of 3-Br Q by DBS gel were investigated. Finally, The method for detection rutin was developed based on 3-Br Q/DBS and Rutin-Al(?) complex energy transfer room temperature phosphorescence(ET-RTP). The results are as follows:1. Among the tested different gels, the gel formed by 0.25wt%DBS in DMF/H2O(1/4, V/V) can induce stronger RTP of 3-Br Q. In comparison with the sodium deoxycholate(Na DC) solution reported in the literature, RTP of 3-Br Q/DBS shows shorter standing time and wider suitable p H range from weak acid to strong alkali. The concentration of 3-Br Q can be determined quantitatively by RTP of 3-Br Q/DBS with two linear ranges of 3.0×10-7- 1.0×10-5mol/L and 1.0×10-5- 7.0×10-5mol/L, a detection limit of 4.7×10-8mol/L and an average recovery of 99.0- 104.7%.2. The phosphorescence intensity of 3-Br Q/DBS gels decreased with an increase of temperature,it shows a good linear relationship between phosphorescence intensity and temperature in the range of 15- 65?. The RTP of 3-Br Q/DBS gels showed an excellent “on-off” effect at 10 and 80? and the “on-off” effect remained stable after 10 cycles. It indicates that 3-Br Q/DBS gel is beneficial for the preparation of highly stable and “on-off” reversible RTP sensor devices.3. The phosphorescence lifetime of 3-Br Q in DBS gels was 2.05 ms calculated from the plot of RTP intensity versus decay time. It was found that RTP intensity has not been affected by the presence of oxygen. UV spectrum implied the interaction between imino groups of 3-Br Q and hydroxyl groups of DBS. The hydrophilic quenching reagent potassium iodide was almost unable to quench RTP of 3-Br Q/DBS gels while the hydrophobic quenching reagent benzophenone could quench ?84% of RTP of 3-Br Q/DBS gels; moreover, the RTP intensity was not affected by cationic and anionic ions. The above results revealed that 3-Br Q was entrapped in the hydrophobic ordered supramolecular structure of DBS gels, leading to restricting the thermal motion of 3-Br Q itself and collision with other molecules and minimizing the probability of inactivation of radiation excitation triplet. Therefore, the 3-Br Q/DBS gels exhibit a strong ion-unquenchable RTP.4. The method for detection rutin was developed by using 3-Br Q/DBS gel formed in DMSO/H2 O as an energy donor and Rutin-Al(?) complex as an energy acceptor based on energy transfer(ET-RTP). This method owns two linear ranges which are 0.5 to 40?g/m L and 40 to 100?g/m L, respectively, with a detection limit of 0.44?g/m L, and an average recovery of 98.6%- 104.4%. Compared with UV-Vis spectrophotometry for rutin determination, ET-RTP method shows wider linear range and higher sensitivity. |
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