The obtained value of 12 ± 2 mg/m3 agrees within the measurement error with the data from gas chromatography 9.8 ± 3 mg/m3 (for benzene, 1 ppm = 3.25 mg/m3). It should be noted that the direct verification of the matrix effect of all compounds of natural gas is hardly possible and actually not needed, because some resolved rotational structure is characteristic of only low-atomic molecules listed in Table 1 and multiring hydrocarbon molecules, in which the vibrational-rotational components are partially degenerated. Beside benzene, only toluene pertains to the latter molecules in Table 2whose effect (up to concentrations of 200 mg/m3) on the results of the benzene determination is absent as confirmed by the data in Table 1.