The analysis of gasoline oxygenates by EPA Method 8260B

Gasoline and other fossil fuels are derived from petroleum and consist mainly of compounds containing only carbon and hydrogen atoms. Oxygenates are compounds that contain oxygen atoms in addition to carbon and hydrogen. Methyl tert-butyl ether (MTBE) is the most common fuel oxygenate. MTBE was first introduced into gasoline in 1979 to reduce overall emissions, replace lead and increase octane. In 1992, gasoline with up to 15% MTBE content by volume was used nationally to meet the first federally mandated wintertime reduction of carbon monoxide. With over one million underground fuel tanks in the United States alone, contamination of ground and surface water with oxygenates and gasoline components is a major environmental concern. Storage tanks world-wide potentially will require clean-up in the future. An equally challenging task is the identification and quantitation of these fuel-derived pollutants since compounds such as MTBE and TBA (tert-butyl alcohol) have similar mass spectra and co-elute on many capillary column stationary phases. Regulatory agencies recommend adding TBA to the target list for contaminated sites known to contain MTBE because it is both a breakdown product of MTBE and a gasoline additive. The US EPA has not sanctioned any method specifically for the analysis of oxygenates in gasoline. Environmental laboratories have used a variety of methods to report these analytes, such as US EPA Methods 8015, 8020 and 8260. The analysis of oxygenates by EPA Method 8260B is a common way to increase the level of confidence in chromatographic data over GC methods. Lawrence Livermore National Laboratory has conducted studies indicating that GC/MS is the most reliable method of oxygenate detection in complex gasoline samples regardless of the concentration of the gasoline. This paper will examine the limitations of currently available columns and will show 8260 applications with the addition of oxygenates to the compound list.