Analysis of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) in ground and surface water

The fuel oxygenate methyl tert-butyl ether (MTBE) is one of the most frequently detected volatile organic compounds in groundwater and, thus, has become a priority groundwater pollutant over the last decade. Methods for the quantitative determination and for compound-specific isotope analysis (CSIA) of MTBE and its key degradation intermediate, tert-butyl alcohol (TBA), in ground and surface water are reviewed. These compounds are exclusively analyzed by gas chromatography (GC), mainly with mass spectrometric (MS) detection because of the requirements for selectivity and sensitivity. Sample introduction/enrichment based on direct aqueous injection, headspace analysis, solid-phase microextraction (direct immersion and headspace), and purge-and-trap is discussed. Specific advantages and disadvantages of these techniques are compared and criteria are given for choosing an appropriate method. Furthermore, it is shown that CSIA can be used to determine the isotopic composition of MTBE and related compounds in the low mug/L range and will therefore become an invaluable tool in the characterization of the environmental fate of such pollutants. (C) 2003 Published by Elsevier B.V.