Determination of fluorescence lifetimes of solvated ions using TRLFS

使用TRLFS测定荧光寿命

时间分辨激光诱导的荧光光谱（TRLF）是通过记录荧光发射光谱沿亚微常浓度的溶液中欧盟（III）和CM（III）的复杂形成来遵循非常敏感的通用光谱法。为了获得进一步的结构信息，确定荧光寿命。对于我们的研究，使用荧光寿命对配位配体的性质的依赖性。发现荧光寿命随着第一个协调球中的猝灭分子的数量减小而增加。因此，双方的水2,3和醇4分子都会导致荧光猝灭，主要通过电能通过OH功能的振动模式的激发来引起荧光猝灭。在本报告中，我们呈现溶剂化EU（III）和Cm（III）离子的荧光寿命。

Figure 1. Schematic view of the TRLFS setup.

Eu(ClO4)3 is purchased from Alfa-Aesar and used as received. A 2.1·10-5 molL-1 Cm(ClO4)3 solution in 0.1 molL-1 HClO4 which was obtained from a 252Cf source and diluted to 6.7·10-6 molL-1. The isotopic mass distribution of the Cm(ClO4)3 solution is 89.7 % 248Cm, 0.1% 247Cm, 9.4% 246Cm, 0.1% 245Cm, 0.3% 244Cm, and 0.4% 243Cm according to alpha spectroscopy and ICP-MS. The Eu(ClO4)3 solution is prepared by adding 20 µL of a 9.0·10-4 molL-1 aqueous stock solution of Eu(ClO4)3 in 0.01 molL-1 HClO4 into 980 µl 0.01 molL-1 HClO4 resulting in a 1.8·10-5 molL-1 solution of Eu(III). The Cm(ClO4)3 solution is prepared by adding 15 µL of a 6.7·10-6 molL-1 aqueous stock solution of Cm(ClO4)3 in 0.01 molL-1 HClO4 into 985 µL 0.01 molL-1 HClO4 resulting in 1.0·10-7 molL-1 solution of Cm(III). TRLFS measurements are performed using a Nd:YAG-pumped dye laser system [Surelite II laser (Continuum), NARROWscan D-R dye laser (Radiant Dyes Laser Accessories)].

对于EU（III）激发，使用394.0nm和Cm（iii）的波长396.6nm的波长。发射光谱以90°记录到励磁激光束。使用300,900和1200线/ mm光栅炮塔的三叶草SR-303i光谱仪（ANDOR）用于光谱分解。通过ICCD相机（Andor Istar Gen III，A-DH720-18F-O）检测荧光发射。

图2. EU（III FFLOORECENT

在记录荧光之前，有机配体的瑞利散射和有机配体的短期荧光是由1.0μs的延迟时间辨别。增强器的栅极宽度设定为1ms，因此在延迟之后积分荧光衰减的间隔。石英比色皿在T = 25℃下控制温度。图2中示出了实验装置的示意图。1。

溶剂的发射光谱ated Eu(III) species ([Eu(H2O)9]3+) in 0.01 mol L-1 HClO4 shows one broad band with an emission maximum at 593.4 nm for the 5D0?7F1 and a emission maximum at 617.4 nm for the broad 5D0?7F2 transition.5 An example of the orange coloured Eu(III) fluorescence is shown in fig.2.

图3.溶剂化EU（III）发射带作为延迟时间的函数的开发，[EU（III）] = 1.8·10-5mol L-1，在0.01mol L-1 HClO4中。

The fluorescence lifetime of the solvated Eu(III) is obtained by recording emission spectra at different delay times between the laser pulse and the beginning of the detection.

The development of the solvated Eu(III) emission band as function of the delay time is shown in fig. 3.

图4.根据延迟时间的函数，[cm（iii）] = 1.0·10-7mol l-1在0.01mol l-1 hclo4中的溶剂化cm（iii）发射带的开发。

The evolution of the Cm(III) fluorescence spectrum in 0.01 mol L-1 HClO4 resulting from the 6D’7/2?8S’7/2 transition is shown in Figure 4. The solvated metal ion species, [Cm(H2O)9]3+, displays a broad emission band at 593.8 nm.1,3 Fluorescence lifetime data of the solvated Cm(III) is obtained in an analogue procedure as for Eu(III).

对于金属离子，通过将对应于激光脉冲的延迟时间T的延迟时间T对应于I（α）= I0（-T / T）之后的延迟时间t，可以获得荧光寿命T.

Figure 5. Decay of the fluorescence intensity of solvated Eu(III) and Cm(III) ions in 0.01 mol L-1 HClO4.

For Eu(III) a fluorescence lifetime of t = 108.1 µs and for Cm(III) a fluorescence lifetime of t = 66.5 µs is determined. Figure 5 shows the monoexponential decay of the fluorescence intensity for [Eu(H2O)9]3+ and [Cm(H2O)9]3+.

The new ICCD camera time-resolved spectroscopy setup allows very easy change between different gratings and a much lower detection limit, allowing a significant saving of the applied Eu(III) and Cm(III) material. The standard concentration of Eu(III) solutions used for our research is decreased from 2.0·10-5 mol L-1 to 1.0·10-6 mol L-1 and the concentration of applied Cm(III) solutions from 2.0·10-7 mol L-1 to 1.0·10-8 mol L-1 respectively. Furthermore the program interface is significantly more user friendly. These improvements result in an entirely happy user (see fig. 6).

Figure 6. A happy user.

致谢

We thank Nicole Bauer, Christian Adam and Janina Kasperidus for artwork used in this report.

接触

BjörnB.Beele博士，Chem。Chem。克里斯蒂安M. Ruff，
Karlsruhe Institute of Technology,
Institute for Nuclear Waste Disposal (INE),
P. O. Box 3640,76021 Karlsruhe，德国

邮件：：bjoern.beele@partner.kit.edu
christian.ruff@kit.edu.
Web: www.ine.kit.edu

文学

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Radiochim. Acta 1996, 72, 61-64.

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