Tb-L 配合物， Eu-L配合物中荧光寿命检测方案(分子荧光光谱)

Time-Gated Separation of Lanthanide Luminescence Introduction The distinctive luminescence of lanthanide ions haslong been a challenge for the spectroscopist. Meth-ods to counter the extremely low absorption coeffi-cients and luminescence quantum yields have con-centrated on Protective ligandsto jreduce vibrationalquenching effects by X-H moieties (X=O，N，...). Deuterated solvents (also to reduce quench-ing effects of X-H). ● Antenna chromophores for enhanced absorp-tion (with later energy-transfer to， and lumi-nescence by， the lanthanide). Luminescence from these systems comprisesa number of sharp and well-resolved bands withcharacteristically long lifetimes， roughly 10-10’s， depending upon the degree of quenching.With an integrated phosphorimeter， the SpexFluoroMax-Pallows cconvenient time-gatedmeasurement of lanthanide systems. In this Ap-plication Note， two lanthanide complexes com-prising an encapsulating complex with benzo-phenone antenna chromophore (L， see Fig. 1)and europium (Eu) or terbium (Tb) ions are in-vestigated using time-gated spectroscopy withthe FluoroMax -P. Figure 1. Benzophenone antenna chromo-phore， designated L in the text， complexedwith Eu and Tb. Experiment & Results An excitation source (xenon lamp) flashes (~3 us pulse-width). Detection of the sample’s lu-minescence occurs within a time-window afterthe flash， according to a chosen delay time anddetection-window size. Acquisition of a spec-trum corresponding to any desired time-sliceduring the luminescence decay is possible. Lu-minescence lifetime measurements are made by recording the intensity of a specific wavelengthwith a chosen detection-window size and incre-mented delay time (Fig.2). Figure 2. Schematic showing how time-gatedmeasurements are performed. The individual spectra of Tb-L and Eu-Lcomplexes are shown in Figs. 3 and 4. The re-sulting luminescence spectrum from a mixture ofTb-L and Eu-L (Fig. 5) combines features fromboth Tb-L and Eu-L， acquired with a delay timeof 0.01 ms， and sample window of 10 ms. Thusresults from detection of all the luminescencefrom both species appear in Fig. 5. Time-gatingallows a mixture of the two species to be spec-trally separated， based on their different lifetimes(~0.60 ms for Eu-L，and~1.1 ms for Tb-L). Figure 3. Luminescence spectrum and decayfor Tb-L(aq). Aex= 295 nm； Aem =545 nm. Careful choice of gating parameters allowsspectra from this mixture to be obtained selec-tively from an early time (to minimize Tb-L andmaximize Eu-L) and a late time (with negligibleEu-L， approximating pure Tb-L)， as shown inFig. 6. A time-gated matrix scan (Fig. 7) shows the dependence of the spectral profile with time.A number of complete emission spectra wererecorded while automatically incrementing thedelay time between each run. The result is a 3-Darray， with intensity， wavelength， and time in-formation. Conclusions The Spex FluoroMax-P spectrofluorometer withintegral flash-lamp can perform time-gated spectro-scopic separation of mixtures of chemical species. Acknowledgements We thank Drs. Andrew Beeby and Gareth Wil-liams of the Chemistry Department， Universityof Durham， UK， for useful discussion and prepa-ration of the compounds studied herein. Figure 4. Luminescence spectrum and decayfor Eu-L(aq). Aex=295 nm；Aem=614 nm. Figure 5. Luminescence spectrum for mixedaqueous Tb-L and Eu-L. Aex= 295 nm， delay=0.010 ms， and sample window = 10 ms. Figure 7. Time-gated matrix scan showingwavelength- and time-dependence of mixedaqueous Tb-L and Eu-L luminescence. >c Figure 6. The principle of time-gated spectral separation for the mixture of Tb-L and Eu-L. Thecontribution from Eu-L is negligible in the spectrum recorded with the late time window. In the USA： Copyright C Jobin Yvon Inc.Printed in USA EMISSION·FLUORESCENGE·FORENSICS·GRATINGS E OEM·RAMAN·SPECTROSCOPIC SYSTEMS· THIN FILMS The Spex ® FluoroMax ®-P spectrofluorometer with integral flash-lamp can perform time-gated spectroscopic separation of mixtures of chemical species.