Novel Analytical Methods for the Determination of Fuel Oxygenates in Water

Abstract

AbstractFuel oxygenates such as methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME) today are among the most frequently detected volatile organic compounds in groundwater and, thus, they have become priority groundwater pollutants over the last decade. Thus, their quantitative determination at very low concentrations is routinely required. Methods for this purpose and for compound-specific isotope analysis (CSIA), especially of MTBE and its key degradation intermediate tert-butyl alcohol (TBA) in ground and surface water are reviewed in this work. For quantitative determination, fuel oxygenates are almost exclusively analyzed by gas chromatography, mainly with mass spectrometric detection due to selectivity and sensitivity requirements. Sample introduction/enrichment based on membrane introduction mass spectrometry, direct aqueous injection, headspace analysis, purge trap, solid-phase microextraction (direct immersion or headspace) and other microextraction approaches such as solid phase dynamic extraction and liquid-phase microextraction are discussed. Furthermore, the use of ion mobility spectrometry for the determination of fuel oxygenates and related compounds is reviewed. Specific advantages and disadvantages of these techniques are compared and criteria for the choice of an appropriate method are given. The application of CSIA nowadays can be used to determine the isotopic composition of MTBE and related compounds in the low μgL–1 range and thus will become an invaluable tool in the characterization of the environmental fate of such pollutants. Therefore, an overview of analytical aspects of this technique is included here.KeywordsFuel oxygenatesMTBETBAGCCSIA