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AVOIDING HYDROLYSIS OF FUEL ETHER OXYGENATES DURING STATIC HEADSPACE ANALYSIS
Citation:
Lin, Z., D. Fine, AND J T. Wilson*. AVOIDING HYDROLYSIS OF FUEL ETHER OXYGENATES DURING STATIC HEADSPACE ANALYSIS. ENVIRONMENTAL SCIENCE & TECHNOLOGY 37(21):4994-5000, (2003).
Description:
A headspace autosampler, gas chromatograph and ion trap mass spectrometer (headspace GC/MS) were used for trace analysis of fuel oxygenates and related compounds and aromatics in water. A method has been developed for determination of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), diisopropyl ether (DIPE), tert-amyl methyl ether (TAME), ethanol, tert-butyl alcohol (TBA), tert-amyl alcohol (TAA), isopropyl alcohol (IPA), acetone, benzene, toluene, ethylbenzene, xylenes (BTEX) and trimethylbenzenes (TMBs). The method detection limits range from 0.1 to 0.4 g/L for the ethers and aromatics. For alcohols and acetone the method detection limits are: 0.7 g/L for TBA, 14 g/L for ethanol, 1.2 g/L for TAA, 3.1 g/L for IPA and 3.1 g/L for acetone. Recoveries of analytes spiked in lab reagent water and field groundwater samples were in the EPA acceptable range of 100 ? 30%. The impact of ether hydrolysis resulting from sample preservation and preparation was investigated. By using acid preservation at sample collection and neutralizing the sample to above pH 7 before analysis, or by base preservation using trisodium phosphate, ether hydrolysis was avoided. Matrix effects from water containing high concentrations of gasoline were studied. The method yielded accurate results over a broad range of gasoline concentrations (2,500 to 100,000 g/L). The method provides excellent sensitivity and determines a wide range of fuel oxygenates and aromatic compounds in the same analytical run.