ABSTRACT
This chapter deals with the quantitative analysis of single- and multicomponent systems. The system of orthogonal polynomials which gives the best description of the spectrum is selected empirically from the possible variants, the constants used in the calculations are taken from tables. The spectrophotometric measurement of multicomponent systems is principally possible since, to good approximation, absorbance is an additive property in the concentration region usually applied in UV spectrophotometry. It often occurs in the spectrophotometric analysis of drugs that the measurement of the absorbance of the component to be determined is subject to interferences by absorptions from other sources. If the measurement is based on natural light absorption, any intercept on the absorbance axis must be due to experimental error. The concentration of one of the components can be determined on the basis of the Beer-Lambert Law directly from the absorbance measured at certain wavelength.
