Quantification of toxic hydrocarbon target compounds in engine exhaust and air by aluminum oxide porous-layer open-tubular capillary gas chromatography mass spectrometry using isotopically labeled internal standards

A method for the determination of 1,3-butadiene, benzene and toluene in ambient air and engine exhaust is described. Air was sampled with a canister and then analysed by Al2O3-coated porous-layer open-tubular (PLOT) capillary gas chromatography-mass spectrometry. The PLOT column provides better resolution for light hydrocarbons and also alleviates the need of using a sub-ambient oven temperature. While the retention times might change owing to the adsorption of moisture, the use of mass spectrometry for detection and isotopically labeled analytes as the internal standards greatly improved the confidence of identification. The heating of solid deuterated butadiene sulfone provides a convenient method for the preparation of deuterated butadiene standard gas. To couple a wide-bore PLOT column with a bench-top mass spectrometer, a pressure gradient and open split interface were used in order to maintain the chromatographic resolution and limit the running time within a reasonable range.