Multibed needle trap devices for on site sampling and preconcentration of volatile breath biomarkers.

To facilitate their use in trace gas analysis, the adsorption capacity of needle trap devices (NTDs) was increased by combining three adsorbent materials and increasing total adsorbent amount. The use of 22 gauge needles, application of internally expanding desorptive flow technique without cryofocusation and a new on site alveolar sampling method for NTDs provided sensitivity in the parts per trillion range of VOC concentrations without loosing precision or linearity. LODs were 0.4 ng/L for isoprene, 0.5 ng/L for dimethyl sulphide, 0.9 ng/L for 2-butenal, 1.0 ng/L for hexane, 1.2 ng/L for pentane, 2.3 ng/L for hexanal, 5.3 ng/L for pentanal, and 8.3 ng/L for acetone. R of calibration curves were consistently >0.98. Loss of volatile aldehydes during storage for 7 days was less than 10%. Needle trap devices packed with more than one adsorbent material represent a promising alternative to SPE and SPME for analysis of volatile organic compounds in the low parts per billion/parts per trillion range. Crucial problems of clinical breath analysis concerning sensitivity of analytical methods, limited stability, and decomposition of breath compounds during sampling and storage could be solved.