Distinguishing crude oils from heavy fuel oils by polycyclic aromatic hydrocarbon fingerprints Xing Liu, Zhen Wang, Xindong Ma, Hengzhen Xu and Ziwei Yao National Marine Environmental Monitoring Center, Dalian, PR China. E-mail: [email protected] PAH biomarkers are important factors in the identification of the source of spilled oil because of the specificity and high resistance to biodegradation of such biomarkers. A novel method for distinguishing heavy fuel oils from crude oils is proposed in this study. This method comprises gas chromatography mass spectrometry analysis and principal component analysis (PCA) of the diagnostic ratios of selected polycyclic aromatic hydrocarbons (PAHs). The method was applied to 15 heavy fuel oils (B1 to B15) and 32 crude oils (C1 to C32) for distinction. Oil samples were collected from Turkmenistan, Korea, China, Vietnam, Morocco, Algeria, Sultan, Yemen, Saudi Arabia, Argentina, Russia, Indonesia, Brazil, Equatorial Guinea, Angola, and Mauritania. The discriminative power of PCA was enhanced through the selection of typical PAH diagnostic ratios, which could be used to distinguish petrogenic from pyrogenic PAHs. The heavy fuel oils have higher An/P, BaA/C, 2-m-An/total of MP, and PI, as well as lower ΣN/ΣC, ΣP/ΣC, ΣD/ΣC, and ΣF/ΣC as compared with crude oils. PCA based on 10 PAH diagnostic ratios is a more efficient method in distinguishing heavy fuel oils and crude oils compared with the plotting of An/P and PI ratios. The method was confirmed to be highly efficient for distinguishing heavy fuel oils from crude oils, with a rapid and objective procedure under comprehensive considerations. The method provides a useful tool to apportion the spilled oil in the marine environment.