Schmid Thomas
Institute of Hydrochemistry, Technische Universität München, Marchioninistr. 17, 81377 Munich, Germany.
Anal Bioanal Chem. 2006 Mar;384(5):1071-86. doi: 10.1007/s00216-005-3281-6. Epub 2005 Jun 7.
Photoacoustic spectroscopy (PAS) is based on the absorption of electromagnetic radiation by analyte molecules. The absorbed energy is measured by detecting pressure fluctuations in the form of sound waves or shock pulses. In contrast to conventional absorption spectroscopy (such as UV/Vis spectroscopy), PAS allows the determination of absorption coefficients over several orders of magnitude, even in opaque and strongly scattering samples. Small absorption coefficients, such as those encountered during trace gas monitoring, can be detected with cells with relatively short pathlengths. Furthermore, PA techniques allow absorption spectra of solid samples (including powders, chips or large objects) to be determined, and they permit depth profiling of layered systems. These features mean that PAS can be used for on-line monitoring in technical processes without the need for sample preparation and to perform depth-resolved characterization of industrial products. This article gives an overview on PA excitation and detection schemes employed in analytical chemistry, and reviews applications of PAS in process analytical technology and characterization of industrial products.
光声光谱法（PAS）基于被分析物分子对电磁辐射的吸收。通过检测声波或冲击脉冲形式的压力波动来测量吸收的能量。与传统吸收光谱法（如紫外/可见光谱法）相比，即使在不透明且强散射的样品中，PAS也能测定跨越几个数量级的吸收系数。对于痕量气体监测中遇到的小吸收系数，可以使用具有相对较短光程长度的样品池进行检测。此外，光声技术可用于测定固体样品（包括粉末、芯片或大型物体）的吸收光谱，并能对分层系统进行深度剖析。这些特性意味着PAS可用于技术过程中的在线监测，无需样品制备，还能对工业产品进行深度分辨表征。本文概述了分析化学中采用的光声激发和检测方案，并综述了光声光谱法在过程分析技术和工业产品表征中的应用。
