A microfabricated preconcentration device for breath analysis

Breath analysis promises to be a noninvasive method for diagnosis of lung cancer in its early stages. Certain ketones and aldehydes in exhaled breath have been identified as indicators of lung cancer. We report a preconcentration device or preconcentrator with thousands of micropillars fabricated from a silicon wafer that have been engineered to selectively trap trace gaseous ketones and aldehydes in exhaled breath. The micropillar surfaces were functionalized with a quaternary ammonium aminooxy salt, 2-(aminooxy)ethyl-N,N,N-trimethylammonium iodide (ATM), for capturing trace carbonyl compounds flowing through the preconcentrator by means of an oximation reaction. The unreacted ATM and reacted ATM adducts were eluted out of the preconcentrator with methanol and were directly analyzed by Fourier transform-ion cyclotron resonance mass spectrometry (FTICR-MS). The preconcentration results indicate that the capture percentages of acetone depend on the molar ratio of ATM/acetone. The analysis of exhaled breath demonstrates that the preconcentrator is suitable for quantitative analysis of ketones and aldehydes in exhaled breath.