Research Of Identification Method For The Oil Spills Based On ATR-FTIR And GC-FID

With the rapid development of economy,the maritime traffic is becoming increasingly busy.The renewal of offshore oil exploration and exploitation technology,the pollution risk of oil leakage is increasing year by year.Since oil spill may be influenced by photooxidation,emulsification and wave breaking in the weathering process,it is very difficult to obtain evidence of offshore oil spill accidents and find the responsible party of oil spill pollution accidents in a short time.At the same time,the oil spill pollution accident will also cause the death of a large number of seabirds and fish,affect the health of the cleaning personnel,and the local fishery.Therefore,relevant departments(such as maritime law-enforcing department,administrative department in charge of transportation)should quickly and accurately identify and determine the pollution sources of oil spill,find the responsible party of oil spill accident,and take effective cleaning measures for the oil spill sea area.Combined with Fourier transform infrared spectroscopy and gas chromatography,this study analyzed the weathering characteristics of oil functional groups and the changing characteristics of n-alkanes content of 0#diesel oil,-35#diesel oil,Daqing crude oil,Inner Mongolia crude oil and 120#fuel oil in the weathering process in spring,summer,autumn,winter and 40 days' short-term weathering.This paper also explored the internal coupling law of the two identification methods,established the oil fingerprint coupling model of infrared spectrum and gas chromatography to determine the variety of spilled oil quickly and accurately.The results showed that different varieties of oil could be distinguished by the difference of infrared spectrogram.Though the infrared spectrum of diesel oil and crude oil were similar,there were still some differences,which could be distinguished by 2950 cm-1.absorbance.In the fingerprint area of the infrared spectrogram of 120#fuel oil,there are many absorption peaks between 900 cm-1 and 600 cm-1 and an obvious characteristic absorption peak at about 1600 cm-1,which had a significant contrast with the infrared spectrum of diesel oil and crude oil.The gas chromatograms of diesel oil,crude oil and fuel oil were significantly different due to their completely different distribution of alkanes.When it was not weathered,the content of n-alkanes in diesel oil was distributed between n-C7?n-C27;the content of n-alkanes in crude oil was distributed between n-C9?n-C40;the content of n-alkanes in 120#fuel oil was distributed between n-C12?n-C40.During the weathering process,the lost n-alkanes of diesel oil due to weathering was distributed between n-C16?n-C20;the lost n-alkanes of crude oil due to weathering was distributed between n-C19?n-C30;the lost n-alkanes of fuel oil due to weathering was distributed between n-C22?n-C30.By exploring the internal coupling law between the infrared spectrum,gas chromatography of 0#diesel oil,-35#diesel oil,Daqing crude oil,Inner Mongolia crude oil and the time,this paper established the relationship curve of infrared spectrum wave number at about 1600 cm-1 absorbance and time,the coupling relationship between infrared spectrum wave number OF about 720 cm-1 absorbance,the proportion of diesel oil n-C16?n-C20 in total n-alkanes content in gas chromatography,and the proportion of crude oil n-C19?n-C26 in total n-alkanes content,and the correlation curves of infrared spectrum wave number of about 1600 cm-1 and 720 cm-1 in different seasons so as to estimate the weathering time of different seasons based on infrared spectrum.Through the coupling model of infrared spectrum and gas chromatography,the proportion of medium chain alkanes in total n-alkanes in different oils was obtained,so that the species of spilled oil could be determined quickly and accurately.Use SPSS software to test the correlation between the calculated value of the coupled model and the real measured value.The test results showed that the calculated value of the same oil sample was strongly correlated with the measured value,and the r value was greater than 0.6.The calculated values of different oil samples were weakly correlated with or even independent of the measured values,and the r values were all less than 0.4.It shows that the coupling model of infrared spectrum and gas chromatography can accurately distinguish 0#diesel oil and-35#diesel oil,daqing crude oil and Inner Mongolia crude oil,and can be used to identify the same kind of oil samples,so as to provide a scientific basis for Marine disaster prevention and mitigation in China and safeguarding national maritime rights and interests.