The Study On Identification Of Chemical Fingerprints Between Marine Fuel Oil And Crude Oil

In recent years, the black oil of unknown origin sometime occur on Bohai and Jiaodong bay, it caused serious contamination to the local marine environment and aquaculture. Because of the appearance of marine fuel oil oil is very similar to crude oil, such as liquid, dark brown and sticky, it is very difficult to identify them by naked eye, and trace to the source and investigate accident or wreckers responsibility. Therefore, it is necessary that the analysis of chemical composition of marine fuel oil and crude oil, and providing their chemical fingerprint characteristics.One marine fuel oil and three crude oils are selected as samples in this work, and these samples were weathered 20 days. The ratio of nickel to vanadium (Ni/V), fluorescence characteristic, n-alkanes, diagnosis ratios (Pr/Ph, Pr/C17, Ph/C18) and carbon stable isotopes ratio (813C) were detected by the graphite furnace atomic absorption spectrometry, constant wavelength synchronous fluorescence spectrophotometry, gas chromatography and stable isotopes ratio mass spectrometry, respectively. The chemical fingerprint characteristics of marine fuel oil and crude oils were described in contrast with changes of these parameters before and after weathering. The experimental results show that their chemical fingerprints are apparently different as follows.Marine fuel oil:①Ni/V is ranged from 27.6 to 33.7;②△λ=35 nm, fluorescence spectrum presents a peak, and the strongest fluorescence intensity is at 328 nm;③n-alkanes less than n-C25 are main components, among＜n-C13 obviously reduced with weathering;④Pr/Ph is higher than Ph/C17 and Pr/C18, Pr/C17 is close to Ph/C18;⑤δ13C of n-Cn～n-C24 are ranged from-28.5 to-33.6.Malaysia crude oil:①Ni/V is ranged from 9.7 to 13.5;②△λ=35 nm, fluorescence spectrum presents two peaks, and the strongest fluorescence intensity is at 328 nm;③n-alkanes less than n-C35 are main components, among＜n-C13 obviously reduced with weathering;④Pr/Ph is higher than Ph/C17 and Pr/C18, Pr/C17 is about 2 times than Ph/C18;⑤δ13C of n-Cn～n-C24 are ranged from-26.3 to-27.6. Iraq crude oil:①Ni/V is ranged from 0.8 to 1.1;②△λ,=35 nm, fluorescence spectrum presents a peak, and the strongest fluorescence intensity is at 332 nm;③n-alkanes less than n-C34 are main components, among≤n-C13 are obviously reduced with weathering;④Pr/Ph＞Ph/C18＞Pr/C17;⑤δ13C of n-C12～n-C23 are ranged from-27.0 to-28.6.Daqing crude oil:①Ni/V is ranged from 63.7 to 74.1;②△λ=35 nm, fluorescence spectrum presents a main peak and a few small peak, and the strongest fluorescence intensity is at 332 nm;③n-alkanes less than n-C35 are main components, among≤n-C13 are obviously reduced with weathering;④Pr/Ph＞Ph/C17 and Pr/C18, Pr/C17 is close to Ph/C18;⑤δ13C of n-C11～n-C24 are ranged from-30.5 to-32.0.In addition, the crude oils with similar n-alkanes components (such as Malaysia crude oil and Daqing crude oil) can be further confirmed through the Ni/V, fluorescence intensity andδ13C.