Determination of Vapors of Cumene-Propanol Mixtures by Single-Beam Infrared Spectrophotometry

Abstract

Abstract This investigation shows that the vapor concentration of a mixture of cumene and propanol in an animal exposure chamber can be determined by single-beam infrared spectrophotometry. The method is not influenced by deviations from Beer's law and is not dependent on the possibility of selecting wavelengths where only one of the substances absorbs the light. The determination was based on a calibration with the substances in four combinations of concentrations at two different wavelengths. A chamber trial (i.e., operating the exposure system without the presence of animals) was carried out, and the absorbance of the gas-air mixture was measured at the two wavelengths. The exposure experiment with animals was then carried out under exactly the same conditions, and the concentration in air was monitored at one of the wavelengths to ensure that no change occurred in the experimental conditions. The method was evaluated in a real toxicological investigation dealing with interactions between two solvents and was found valuable. As the analytical method is in no way limited to the two substances in case, we consider that infrared spectrophotometry offers an easy analytical method when dealing with experiments involving two-component gas mixtures.