红外光谱(IR)测量中对制样的基本要求是样品要均匀。实际工作中经常遇到厚度或浓度分布不均匀的样品, 如含气泡的液体等。 通过理论模型结合实验结果定量分析了厚度或浓度分布不均匀样品的红外光谱失真问题, 对此类不均匀样品的光谱性质做了深入研究和系统分析。 理论计算和实验结果均表明, 只要能够合适地控制实验条件, 如制备足够薄的样品或选择吸收较弱的IR峰做分析对象, 则厚度或浓度分布不均匀样品的光谱与均匀样品的光谱是高度相似的, 完全可以满足定性或定量分析的要求。

The samples to be measured with infrared instrument are usually required to be homogeneous. However, discontinuous sample is quite common in the real infrared measurements, such as, high viscosity liquids containing air bubbles. In this paper, the spectral distortion of discontinuous sample was analyzed with simple theoretical simulation and experimental examples quantitatively. The spectral properties of the discontinuous sample were studied and discussed systematically. Both theoretical computation and experimental results demonstrated that the infrared spectrum of a discontinuous sample was highly similar to that of the uniform sample if suitable experimental conditions were adopted. Our results showed that if infrared samples can be prepared to be thin enough, the infrared spectrum of the discontinuous sample can fulfill the requirements of analysis work nearly perfectly.