Quantitative Characterization of the Molecular Absorption Spectra in the Ultraviolet Region by Gas Chromatography

Abstract

ABSTRACTThe aim of this study was to obtain quantitative characteristics of the ultraviolet absorption spectra as the molecular absorptivity at the wavelength of maximum absorbance. Organic as well as inorganic compounds were explored. A gas chromatography—ultraviolet absorption instrument has been used in the quantitative study of molecular ultraviolet absorption spectra in the vapour phase. The wavelength range studied was between 168 and 330 nm. The absorbance of 170 compounds was determined relative to perchloroethylene and their molecular absorptivities were calculated. For various groups of compounds, these relative absorptivities varied within two to three orders of magnitude. Standard curves were linear within four orders of magnitude from limit of quantification up to an absorption value of 1.5 absorbance units. The noise level was 3 × 10−5 absorbance units peak to peak at a bandwidth of 1.7 nm and a wavelength range from 180 to 330 nm was preferred. The detection limit for mesitylene was calculated to be 2 pg/s and for naphthalene 1 pg/s with 4 s store cycle time.