Fingerprinting of crude oil using fluorescence spectroscopy

Abstract

Crude oil is a complex mixture of hydrocarbons (e.g. paraffins, aromatics, napthenes), sulphur compounds (e.g. sulphur, sulphides), amines, metals (e.g. Ni, Fe) and salts (e.g. NaCl, sand). Quantitative chemical analysis of such combinations is difficult and requires partial or complete separation of the components, challenging outside of the laboratory. Qualitative chemical analysis of oil is simpler using techniques such fluorescence spectroscopy. In this paper we will present fluorescence (spectra and lifetime) data for crude oil samples of varying (specific) API gravity and show how qualitative chemical information can be extracted from the spectra. This will include data obtained using synchronous scanning fluorescence spectrometry (SS) and time-resolved emission spectroscopy (TRES) and demonstrate the ability of utilising these methods to obtain better qualitative chemical information and hence the ability to " fingerprint " crude oil.