A Novel MEMS Preconcentration Approach for Analysis of Ketones and Aldehydes In Breath

A Novel MEMS Preconcentration Approach for Analysis of Ketones and Aldehydes in Breath

 

Mingxiao Li^a, Souvik Biswas^b, Michael H. Nantz^b, Richard M. Higashi^b,c,d,  Xiao-An Fu^*a,

Departments of ¹Chemical Engineering and ²Chemistry, ³Center for Regulatory and Environmental Analytical Metabolomics (CREAM), and ⁴ James Graham Brown Cancer Center,

The analysis of exhaled breath is a promising non-invasive diagnostic method for early detection of lung diseases. Certain volatile organic compounds (VOCs), such as ketones and aldehydes in exhaled breath, have already been recognized as metabolic indicators of many diseases including lung cancer and chronic obstructive pulmonary disease (COPD).

We report a MEMS-based micropreconcentrator that has been engineered to selectively preconcentrate ultra-trace gaseous ketones and aldehydes in exhaled breath. The silicon-glass micro-preconcentrator has outer dimensions of 14mm×14 mm, total inner surface area of ~300mm², and a total inner volume of ~7 µL. The surface of the preconcentrator is functionalized with a quaternary ammonium aminooxy compound, for preconcentrating trace carbonyl VOCs by means of an oximation reaction. The concentrated ketone- and aldehyde- adducts are directly analyzed by Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer (MS). We demonstrate the utility and enhanced sensitivity of this approach in the detection of  C1- to C12 ketones and aldehydes in exhaled breath.