The problem of using octanometers for the rapid control of the octane number of compounds in the production of commercial gasoline is considered, and the factors forming it are indicated. Error spectra of a multidimensional absorption spectral analytic signal of commercial gasolines and compounds of their individual fractions (components) were studied in measurements in the mid-IR region. The effect of a change of the proportion of the main constituents (aromatic hydrocarbons, benzene catalysate, isomerizate, methyl tert-butyl ether, and isopentane) in the compound on the spectra of commercial gasolines was evaluated. Multidimensional measurements of light absorption by gasolines in a wide spectral region and difference spectra were used. It was shown that spectral noise does not form limitations in spectroscopic measurements, while uncontrollable variations in the process conditions can form significant deviations in the absorption spectra, leading to problems in using calibration characteristics based on commercial gasoline samples.