混合物的光谱是其组份光谱的叠加,直接对它进行解析是十分困难的,所以光谱工作者要在化学分离上耗费大量精力。富里埃变换红外光谱仪及其它计算机化的红外光谱仪器具有被称为吸光度减的功能,可用以进行光谱之间的带权相减。它在一定程度上代替了化学分离,把各组份的光谱从混合物光谱中一一“剥离”开来。此技术可广泛用于混合物分析和涉及混合物的研究工作。Koenig曾对此技术的应用作过 The spectrum of a mixture is a superposition of the spectra of its components, and it is very difficult to resolve it directly, so spectrum workers have to spend a lot of effort on chemical separation. The Fourier transform infrared spectrometer and other computerized infrared spectrometers have a function known as absorbance subtraction that allows for the subtraction of spectra between spectra. It has to some extent replaced the chemical separation, the spectrum of each component from the mixture one by one “peeled off”. This technology is widely used for mixture analysis and research involving mixtures. Koenig has done this technology