Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland.
Rev Sci Instrum. 2021 Dec 1;92(12):123001. doi: 10.1063/5.0068227.
A stop-flow sample delivery system for transient spectroscopy is presented, which is, in particular, suited for laser-based instruments (quantum-cascade lasers or amplified femtosecond lasers) with excitation pulse repetition rates in the range 10-100 Hz. Two pulsing micro-valves are mounted onto a flow cuvette designed for transient IR spectroscopy, which is integrated into a flow cycle driven by a peristaltic pump. The performance of the system is demonstrated with transient IR experiments of the trans-to-cis photoisomerization of a water-soluble azobenzene derivative. The sample stands still when the micro-valves are closed and is pushed out from the probe beam focus on a 1 ms timescale when opening the micro-valves. The setup is extremely sample efficient. It needs only small sample volumes, and at the same time, it enables excitation of a large fraction of molecules in solution.
介绍了一种用于瞬态光谱学的停流样品输送系统，该系统特别适合于基于激光的仪器（量子级联激光器或放大飞秒激光器），其激发脉冲重复率在 10-100 Hz 范围内。两个脉冲微阀安装在为瞬态红外光谱设计的流动比色皿上，该比色皿集成到由蠕动泵驱动的流动循环中。通过水溶性偶氮苯衍生物的顺反光异构化的瞬态红外实验来证明该系统的性能。当微阀关闭时，样品处于静止状态，当微阀打开时，样品在 1 ms 的时间尺度上从探针光束焦点推出。该设置具有极高的样品效率。它只需要少量的样品体积，同时能够激发溶液中很大一部分分子。
