A Comprehensive Two-Dimensional Gas Chromatography Method for Analyzing Extractable Petroleum Hydrocarbons in Water and Soil
A flow-switching two-dimensional gas chromatography (GC×GC) apparatus has been constructed that can operate at temperatures as high as 340°C. This system is employed to analyze complex hydrocarbon mixtures such as diesel fuel, gas-oil, motor oil, and petroleum contaminated environmental samples. The GC×GC system generates two-dimensional chromatograms with minimal overlap between the aliphatic and aromatic regions. This allows these compound classes to be independently quantitated without prior fractionation. The GC×GC system is used to analyze extracts of spiked water samples, wastewater, and soil. The accuracy of the method is compared to that of the Massachusetts Extractable Petroleum Hydrocarbons (MA EPH) method. The GC×GC system generates a quantitative accuracy similar to the MA EPH method for the analysis of spiked water samples. The GC×GC method and the MA EPH method generate comparable levels of total hydrocarbons when wastewater is analyzed, but the GC×GC method detects a significantly higher aromatic content and lower aliphatic content. Both the GC×GC method and MA EPH method measure comparable levels of aromatics in the soil samples.