利用散射光增强弱吸收固体混合物中主要光吸收物质的光声光谱特征

在传统的透射和反射光谱中, 散射光通常是误差的主要来源之一, 然而对光声光谱, 散射光有可能成为促进光谱测量的积极因素. 本文研究了弱吸收固体混合物–-奥氮平药片及其粉末的光声光谱. 为了排除光声池吸收散射光所产生背景光声信号的干扰, 取试样与其空白物的差值谱进行碳黑归一化, 得到了只与试样自身性质相关的归一化光声光谱.实验发现通过将药片碾成粉末, 可以使奥氮平药片的主成分奥氮平原料药的光声光谱特征凸显出来. 分析表明光散射效应是这一现象产生的主要原因. 传统光谱技术的障碍–-散射光却能促进光声光谱测量, 这显示出光声技术在光谱测量领域的独特优势. 上述实验提供了一种初步快速鉴别弱吸收固体混合物中少量光吸收物质的新方法, 这一方法有望应用于固体药物、矿物和土壤分析等领域.关键词：光声光谱散射光弱吸收固体混合物奥氮平

Using scattered light to amplify the photoacoustic spectroscopic signatures of the main absorbing material in a weakly light-absorbing solid mixture

Scattered light by the sample is usually one of the main error source in conventional transmission spectroscopy and diffuse reflection spectroscopy. However, scattered light may be useful for photoacoustic spectroscopy measurement. In the present experiment, the photoacoustic spectra of an olanzapine drug tablet and its powder are studied. The olanzapine tablet is a weakly light-absorbing solid mixture and its main constituent is olanzapine. In order to eliminate the background signal produced by the photoacoustic cell wall due to absorbing the scattered light by the sample, the difference between the photoacoustic spectrum of the sample and that of its base is taken and normalized with the photoacoustic spectrum of carbon black. It is found that the photoacoustic spectroscopic signatures of olanzapine in the olanzapine table become obvious when the olanzapine table is powdered. This is the result of the internal light scattering effect in the sample. The scattered light which serves as an obstacle in conventional optical spectroscopy techniques, however, facilitates the photoacoustic spectroscopy measurement. This indicates the particular advantage of photoacoustic spectroscopy. A new method to preliminarily fast identify the main absorbing component in a weakly light-absorbing solid mixture is proposed based on the above experiment. This method can be applied to the field of solid drug and mineral and soil and so on.
Keywords：photoacoustic spectroscopyscattered lightweakly light-absorbing solid mixtureolanzapine