Molecular Microspectroscopy Laboratory, Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, USA.
Appl Spectrosc. 2010 Jan;64(1):15-22. doi: 10.1366/000370210792966161.
The benefits of an attenuated total reflection Fourier transform infrared (ATR-FTIR) imaging approach for kidney biopsy analysis are described. Biopsy sections collected from kidney-stone formers are analyzed at the initial stages of stone development to provide insights into stone growth and formation. The majority of tissue analysis currently conducted with IR microspectroscopy is performed with a transflection method. The research presented in this manuscript demonstrates that ATR overcomes many of the disadvantages of transflection or transmission measurements for tissue analysis including an elimination of spectral artifacts. When kidney biopsies with small mineral inclusions are analyzed with a transflection approach, specular reflection and the Christiansen effect (anomalous dispersion) can occur, leading to spectral artifacts. Another effect specific to the analysis of mineral inclusions present in kidney biopsies is known as the reststrahlen effect whereby the inclusions become strong reflectors near an absorption band. ATR eliminates these effects by immersing the sample in a high index medium. Additionally, the focused beam size for ATR is decreased by a factor of four when a germanium internal reflection element is used, allowing the acquisition of spectra from small mineral inclusions several micrometers in diameter. If quantitative analysis of small mineral inclusions is ultimately desired, ATR provides the photometrically accurate spectra necessary for quantification.
本文介绍了衰减全反射傅里叶变换红外（ATR-FTIR）成像方法在肾活检分析中的应用。从结石形成者的肾活检组织中采集样本，在结石形成的初始阶段进行分析，以深入了解结石的生长和形成过程。目前，大多数采用红外光谱显微镜进行的组织分析都是采用反射法进行的。本文介绍的研究表明，ATR 克服了反射或透射测量在组织分析中存在的许多缺点，包括消除光谱伪影。当采用反射法分析含有小矿物包裹体的肾活检组织时，可能会出现镜面反射和克里斯琴森效应（异常色散），导致光谱伪影。另一种特定于分析肾活检组织中矿物包裹体的效应称为瑞利后向散射效应，即包裹体在吸收带附近成为强反射体。ATR 通过将样品浸入高折射率介质中消除了这些效应。此外，当使用锗内反射元件时，ATR 的聚焦光束尺寸减小了四倍，允许从直径几微米的小矿物包裹体中获取光谱。如果最终需要对小矿物包裹体进行定量分析，ATR 则提供了进行定量所需的光度准确的光谱。
