EPA Method 5030C

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.