Analysis of a Three-component Drug Mixture

The quantitative analysis of a multicomponent system is illustrated by its application to the simultaneous determination, of aspirin, phenacetin and caffeine in tablets. These drug components can be determined by dissolving the sample in chloroform, with each of the components showing distinct carbonyl bands in the infrared spectrum. 

we need to measure the absorbances of the carbonyl bands of each of the drug components by using standard solutions. Typical results that are obtained are shown in Table 5.6a. 

we can apply the Beer-Lambert law (discussed in Section 5.4) to determine the molar absorptivity for each component  

Each of the standards was examined by using a 0.1 mm pathiength NaCl transmission cell. 

Examination of the infrared spectrum of the unknown sample, produced under the standard sample conditions, gave the data listed in Table 5,6b. 

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