Suppr超能文献

使用皮秒门控增强型电荷耦合器件相机的共振拉曼光谱中的荧光抑制

Fluorescence rejection in resonance Raman spectroscopy using a picosecond-gated intensified charge-coupled device camera.

作者信息

Efremov Evtim V, Buijs Joost B, Gooijer Cees, Ariese Freek

机构信息

Department of Analytical Chemistry and Applied Spectroscopy, Laser Centre Vrije Universiteit Amsterdam, the Netherlands.

出版信息

Appl Spectrosc. 2007 Jun;61(6):571-8. doi: 10.1366/000370207781269873.

Abstract

A Raman instrument was assembled and tested that rejects typically 98-99% of background fluorescence. Use is made of short (picosecond) laser pulses and time-gated detection in order to record the Raman signals during the pulse while blocking most of the fluorescence. Our approach uses an ultrafast-gated intensified charge-coupled device (ICCD) camera as a simple and straightforward alternative to ps Kerr gating. The fluorescence rejection efficiency depends mainly on the fluorescence lifetime and on the closing speed of the gate (which is about 80 ps in our setup). A formula to calculate this rejection factor is presented. The gated intensifier can be operated at 80 MHz, so high repetition rates and low pulse energies can be used, thus minimizing photodegradation. For excitation we use a frequency-tripled or -doubled Ti : sapphire laser with a pulse width of 3 ps; it should not be shorter in view of the required spectral resolution. Other critical aspects tested include intensifier efficiency as a function of gate width, uniformity of the gate pulse across the spectrum, and spectral resolution in comparison with ungated detection. The total instrumental resolution is 7 cm(-1) in the blue and 15 cm(-1) in the ultraviolet (UV) region. The setup allows one to use resonance Raman spectroscopy (RRS) for extra sensitivity and selectivity, even in the case of strong background fluorescence. Excitation wavelengths in the visible or UV range no longer have to be avoided. The effectiveness of this setup is demonstrated on a test system: pyrene in the presence of toluene fluorescence (lambda(exc) = 257 nm). Furthermore, good time-gated RRS spectra are shown for a strongly fluorescent flavoprotein (lambda(exc) = 405 nm). Advantages and disadvantages of this approach for RRS are discussed.

摘要

组装并测试了一台拉曼仪器,该仪器通常能去除98% - 99%的背景荧光。利用短(皮秒)激光脉冲和时间选通检测来在脉冲期间记录拉曼信号,同时阻挡大部分荧光。我们的方法使用超快选通增强型电荷耦合器件(ICCD)相机,作为皮秒克尔选通的一种简单直接的替代方案。荧光去除效率主要取决于荧光寿命和选通门的关闭速度(在我们的装置中约为80皮秒)。给出了计算该去除因子的公式。选通增强器可在80兆赫兹下运行,因此可以使用高重复率和低脉冲能量,从而将光降解降至最低。对于激发,我们使用脉冲宽度为3皮秒的三倍频或倍频钛宝石激光器;考虑到所需的光谱分辨率,脉冲宽度不应更短。测试的其他关键方面包括增强器效率与选通宽度的函数关系、选通脉冲在整个光谱上的均匀性以及与非选通检测相比的光谱分辨率。仪器的总分辨率在蓝光区域为7厘米⁻¹,在紫外(UV)区域为15厘米⁻¹。该装置允许使用共振拉曼光谱(RRS)来提高灵敏度和选择性,即使在背景荧光很强的情况下也是如此。不再需要避免可见光或紫外范围内的激发波长。在一个测试系统上展示了该装置的有效性:芘在甲苯荧光存在的情况下(激发波长λ = 257纳米)。此外,还展示了一种强荧光黄素蛋白(激发波长λ = 405纳米)的良好时间选通RRS光谱。讨论了这种RRS方法的优缺点。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验