As an alternative to tetraethyl lead, t-Butyl methyl ether (MTBE) has been widely used as an octane enhancer for gasoline. Studies have found increasingly high levels of MTBE in groundwater, often a result of accidental spills or leaking underground storage tanks. In this paper, a method for the determination of MTBE in water and soil was established using the PerkinElmer Clarus® 690 GC/FID with the TurboMatrix™ HS-40 Trap.