Discussion of the Characteristic Indexs in Using Three-Dimensional Fluorescence Method to Identify Different Crude Oils

The present paper investigates the influence of solvent purity on the test of three-dimensional fluorescence spectra,determines the process of its pre-purification,and studies the influence of the concentrations on the three-dimensional fluorescence characteristic indexes such as the characteristic peaks position,fluorescence intensity(F),and ratio(R)of fluorescence intensity when the phenomena of fluorescence quenching won't appear.The result shows that the concentration affects the value F and value R largely but its effect on the relative peak intensity(RS)is relatively small.Different crude oils has different value RS.According to those characteristics,this paper presents that the value RS can be used as a new characteristic index for identification of crude oil.This conclusion was confirmed by testing many crude oils stably and reliably from different areas with their concentrations at 5 mg·L-1.This method can be applied to identify most crude oils preliminary and further accurate analysis can be carried out together with other index.