Characteristic and Discrimination of Unconventional Oil Samples by Two-Dimensional Extraction Combine with Concentration-Resolved Fluorescence Spectroscopy

Fluorescence detection of petroleum related samples has excellent application value for unconventional oil exploration and petrochemical detection. In this paper, based on the concentration-resolved fluorescence spectra, the synchronous fluorescence spectra were used in the range of 3.0 x 10(-3) g/L to 5.0 g/L for different kinds of petroleum samples and petrochemical products with n-hexane and isopropanol as extractants. A red shift of the fluorescence spectra with an increase in the concentration was found under both extractants. The solubility of n-hexane on crude oil was stronger while that of isopropanol was better for aromatic compounds. The results show that the effect of different extracting agents on the spectra can be used to acquire more information about aromatics components in petroleum related samples, which should be carefully considered in the process of quantitative and qualitative analysis of crude oil samples by fluorescence spectra. It is also shown that the combined extraction of different extractants could enhance the analytical ability of the fluorescence spectrometry, and the rapid, non-contact measurement is promising for in-field use.