A stability study of carbonyl compounds in Tedlar bags by a fabricated MEMS microreactor approach

The analysis of volatile organic compounds (VOCs) in exhaled breath has a great potential as a noninvasive approach for early detection of lung cancer and other diseases. The stability of VOCs in sampling bags significantly affects quantification of target VOCs in exhaled breath. Carbonyl compounds are a subset of VOCs in exhaled breath and are more reactive than other VOCs in breath matrix. This work reports the stability of carbonyl compounds in exhaled breath collected in Tedlar bags. A silicon microreactor coated with 2-(aminooxy)ethyl-N, N, N trimethylammonium iodide (ATM) was used for chemoselective trapping trace carbonyl compounds in exhaled breath samples by means of oximation reactions. ATM-carbonyl adducts were measured using an ultra-high-performance liquid-chromatography-mass spectrometry (UHPLC-MS). The results indicate that breath samples stored at ambient temperature can recover more than 80% of carbonyl compounds if the samples are processed within one hour. The recovery percentages of unsaturated aldehydes are much lower than that of saturated carbonyl compounds. The storage of breath samples at cold temperature (4 degrees C) can reduce degradation of carbonyl compounds. The recovery percentages of carbonyl compounds in breath samples of current smokers are slightly lower than that of nonsmokers.