Aromatics, resins and asphaltenes, separated from petroleum products, have been examined by U.V. spectrometry. With suitable data handling of U.V. spectra, the three main absorption regions whose distribution is shown to be characteristic of each hydrocarbon class can be identified. Some U.V. parameters which are shown to depend on the properties of each class are also derived. Some actual petroleum products (ranging from gasoline to some residues and crude oils) were examined, and it is shown that the quoted U.V. parameters are different for the different products and that they are linked to some characteristics of the products. Hence U.V. spectrometry, with the proposed data handling, provides a complementary analytical tool for rapid screening in the petroleum field. Moreover a method is proposed which makes it possible to obtain a direct estimate of the composition of the main components (saturates and unsaturates) for heavy petroleum products, while avoiding steps such as deasphaltation and chromatographic separation.
Such a method has been positively checked for reconstructed heavy fractions. Work is in progress to detect limits and accuracy of the overall procedure.