Abstract
This article describes the development of a method for determining the presence of methyl tert-butyl ether (MTBE), in a matrix of gasoline vapors and in liquid gasoline samples, with the simultaneous analysis of benzene, toluene, xylenes, and total hydrocarbons. An assessment of the method's performance based on field use is also included. The method recommends collection of air samples for MTBE on 400- and 200-mg coconut-shell charcoal tubes in series, desorption in carbon disulfide, split-vent injection, analysis by gas chromatography (GC) using a capillary column, and detection by flame ionization detector. The analysis of liquid gasoline samples is accomplished by direct GC injection. The estimated limit of detection for air samples is 20 μg MTBE per sample, and 0.002 percent MTBE for liquid gasoline samples. The estimated analytical precision of MTBE standards in the range of 9 to 426 μg/mL is 4.5 percent. Samples stored at ambient temperature are stable for at least 5 days. MTBE-spiked samples stored at —7°C for 27 days indicated 90 percent recovery. Air sample volumes of 8 L are recommended when MTBE concentrations are near 10 ppm. Larger volumes should be collected if lower MTBE concentrations are expected. The method was field tested at different service stations in Los Angeles, California, Phoenix, Arizona, and Cincinnati, Ohio, where 121 personal (breathing zone) air samples were collected on charcoal tubes, and 75 liquid gasoline samples were collected and analyzed for MTBE and other gasoline hydrocarbons. The method worked well for all of these samples. The majority of personal exposures to MTBE were near the detection limit. MTBE concentrations in gasoline bulk samples varied from nondetectable to 12.4 percent. Palassis, J.; Hartle, R.W.; Holtz, J.L.: A Method for Determination of Methyl tert-Butyl Ether in Gasoline Vapors and Liquid Gasoline Samples. Appl. Occup. Environ. Hyg. 8(11):964–969; 1993.