Determination of gasoline oxygenates in air using a diffusive sampler

Abstract

The US production of methyl tert-butyl ether (MTBE) for use in oxygenated fuel formulations has risen more than 25% over the past decade as a response to mandates of the US Environmental Protection Agency Clean Air Acts. The SKC 575–001 diffusive sampler containing charcoal was investigated as a method for the collection of MTBE and its homologues ethyl tert-butyl ether (tert-butyl ethyl ether, TBEE) and methyl tert-amyl ether (tert-amyl methyl ether, TAME) from air. The sampler was fully validated for MTBE according to a modified version of the US National Institute for Occupational Safety and Health (NIOSH) protocol for diffusive sampler evaluation, which is similar in scope to the Comite Europeen de Normalisation (CEN) standard EN 838. The test concentrations were based on the American Conference of Governmental Industrial Hygienists threshold limit value of 40 ppm. The sampler collected MTBE efficiently at an uptake rate of 13.65 ml min–1 over the range of conditions studied, with an accuracy within the NIOSH Accuracy Criterion or CEN standard EN 482. The recovery of both TBEE and TAME was acceptable (101% and 99%, respectively), and experimental uptake rates were close to those calculated from theory (13.1 versus 13.3 ml min–1, for both compounds).