Analysis of a broad range of volatile organic compounds in environmental air with dual-compartment micropreconcentrators.

Benzene, toluene, ethylbenzene, and xylene (BTEX) and the aldehydes formaldehyde and acetaldehyde are toxic organic compounds. Currently, there is no single method for sampling and analyzing these compounds in environment air concurrently. We report here a microfabricated dual-compartment micropreconcentrator device that combines physical adsorption of BTEX with derivatization of aldehydes for analysis of all these compounds by GC-MS in a single run. The micropreconcentrator contains two compartments to accommodate two different sorbents. One compartment is packed with Carbopack X to trap BTEX and the other is filled with silica gel particles coated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) to capture aldehydes via oximation. The captured compounds in the micropreconcentrator then are eluted with solvents and analyzed by gas chromatography-mass spectrometry (GC-MS). The dual-compartment micropreconcentrator captures above 90 % of both BTEX and the above aldehydes. The limits of detection (LOD) for these compounds were determined in the range of 0.03-1.2 μg/m3. The dual-compartment device was used to analyze airborne BTEX and carbonyl compounds in air samples.