No abstract

Methyl tert‐butyl ether (MTBE) is one of the most common ground water contaminants in the United States. Ground water contaminated with MTBE is also likely to be contaminated with tert‐butyl alcohol (TBA) because TBA is a component of commercial‐grade MTBE, can also be used as a fuel oxygenate, and is a biodegradation product of MTBE. In California, MTBE is subject to reporting at concentrations >3 μg/L, and TBA has a drinking water action level of 12 μg/L. We describe a simple, automated solid‐phase microextraction (SPME) method for the analysis of MTBE and TBA in water. The headspace (HS) of a water sample is extracted with a carboxen/polydimethylsiloxane SPME fiber and the MTBE and TBA are desorbed into a gas chromatograph (GC) and detected using a mass spectrometer (MS). The method is optimized for the routine analysis of MTBE and TBA, with a level of quantitation of 0.3 and 4 μg/L, respectively, in water. The lower level of detection for MTBE is 0.03 μg/L using this method. This HS extraction SPME is applicable to the measurement of both MTBE and TBA at concentrations below regulatory action levels. This method was compared with the certified U.S. EPA Method 5030/8260B (purge and trap/GC/MS) using split samples. Results from the SPME‐HS/GC/MS method were directly comparable to those from the U.S. EPA Method 5030/8260B. This method provides a simple, inexpensive, accurate, and sensitive alternative to the U.S. EPA Method 5030/8260B for the analysis of MTBE and TBA in water samples.

Methyl tert-butyl ether (MTBE) is now one of the most common groundwater contaminants in the United States. Groundwater contaminated with MTBE is also likely to be contaminated with tert-butyl alcohol (TBA), because TBA is a component of commercial grade MTBE, TBA can also be used as a fuel oxygenate, and TBA is a biodegradation product of MTBE. In California, MTBE is subject to reporting at concentrations greater than 3 µg/L. TBA is classified as a "contaminant of current interest" and has a drinking water action level of 12 µg/L. In this paper, we describe the development and optimization of a simple, automated solid phase microextraction (SPME) method for the analysis of MTBE and TBA in water and demonstrate the applicability of this method for monitoring MTBE and TBA contamination in groundwater, drinking water, and surface water. In this method, the headspace (HS) of a water sample is extracted with a carboxen/polydimethylsiloxane SPME fiber, the MTBE and TBA are desorbed into a gas chromatograph (GC), and detected using mass spectrometry (MS). The method is optimized for the routine analysis of MTBE and TBA with a level of quantitation of 0.3 µg/L and 4 µg/L, respectively, in water. MTBE quantitation was linear for over two orders of concentration (0.3 µg/L-80 µg/L). TBA was found to be linear within the range of 4 µg/L-7,900 µg/L. The lower level of detection for MTBE is 0.03 µg/L using this method. This SPME method using headspace extraction was found to be advantageous over SPME methods requiring immersion of the fiber into the water samples, because it prolonged the life of the fiber by up to 400 sample analyses. This is the first time headspace extraction SPME has been shown to be applicable to the

Fluidized bed bioreactors (FBRs) are frequently used for the treatment of gasoline contaminated groundwater. Due to changes in gasoline formulations in the last decade, gasoline contaminated groundwater may also contain significant quantities of methyl tert-butyl ether (MTBE), a recalcitrant gasoline additive. It has been shown that MTBE is biodegradable and there is interest in determining if MTBE contaminated groundwater can be biologically treated using FBR technology. We examined the biodegradation of MTBE in FBRs treating contaminated groundwater and establish that there was an inverse correlation between total petroleum hydrocarbon (TPH) loading and MTBE treatment efficiency. Follow-up laboratory studies demonstrated that toluene, a component of TPH, is a strong inhibitor of MTBE biotreatment in FBRs.