Oser H, Coggiola M J, Faris G W, Young S E, Volquardsen B, Crosley D R
Appl Opt. 2001 Feb 20;40(6):859-65. doi: 10.1364/ao.40.000859.
The need for a continuous monitor for environmentally important pollutants at realistic [parts-per-trillion (parts in 10(12))] concentrations measured in real time (minutes) is widely recognized. We developed an instrument that is based on supersonic-jet expansion and cooling, followed by resonantly enhanced multiphoton ionization (REMPI) into a mass spectrometer. This approach furnishes the dual selectivity of narrow-band tuned laser absorption and mass analysis. We initiated a spectroscopic characterization of the jet's collisional cooling behavior to optimize the instrument's sensitivity and selectivity, made measurements of several aromatic compounds (including polychlorinated dioxins) by use of a one-color REMPI scheme, and demonstrated a two-color excitation scheme.
实时（以分钟计）监测环境中重要污染物的实际浓度（万亿分之一，即10的12次方分之一）的连续监测仪的需求已得到广泛认可。我们开发了一种基于超音速喷射膨胀和冷却，随后通过共振增强多光子电离（REMPI）进入质谱仪的仪器。这种方法提供了窄带调谐激光吸收和质量分析的双重选择性。我们对喷射流的碰撞冷却行为进行了光谱表征，以优化仪器的灵敏度和选择性，使用单色REMPI方案对几种芳香族化合物（包括多氯二恶英）进行了测量，并展示了双色激发方案。
