Compound-specific carbon stable isotope analysis of 16 polycyclic aromatic hydrocarbons in sediments by Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS)

A method for the compound-specific carbon stable isotope analysis of 16 polycyclic aromatic hydrocarbons (PAHs) in ocean sediments by Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS) was established for monitoring PAHs, tracing pollutant sources and controlling pollution. The compound-specific carbon stable isotope of 16 PAHs was determined by Elementary Analyzer-Isotope Ratio Mass Spectrometry (EA-IRMS) with a peak area deviation of 0.03‰-0.15‰ (n=10) (<0.2‰). The isotope fractionation of the 16 PAHs caused by High Performance Thin Layer Chromatography (HPTLC), injection volume of GC, purge time or sampling concentration was investigated using GC-C-IRMS and PAH-MIX. The results indicated that there was no apparent isotope fractionation during the whole process of analysis. Some calibration curves were obtained according to the changes of GC-C-IRMS data corresponding to the concentrations of PAH-MIX and the differences between GC-C-IRMS and EA-IRMS data, and the R² value was higher than 0.99. The curves were used to determine the compound-specific carbon stable isotope of 16 PAHs in sediments, which offers strong evidence for tracing the source of PAHs in ocean sediments.