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[14p-316-11] Cryo-temperature programmed desorption for exhaled breath analysis
Keywords:temperature programmed desorption
Exhaled breath analysis is a promising medical monitoring method, but the practical use is very limited in the present. This is due to very low concentration of the disease marker, hence the advanced (research-level) analytical instrumentation has been typically employed. We have proposed cryogenic-temperature programmed desorption (cryo-TPD) as a novel simple method of the breath analysis. In cryo-TPD, the disease marker is selectively concentrated by quench condensation at cryogenic temperature combined with subsequent ramped heating. The influence of the interaction between the markers on the thermal desorption (the gas mixing effect) is crucial in the practical breath analysis by cryo-TPD.In the present study, we found that the gas mixing effect causes almost no change in thermal desorption of n-alkanes in the simulated breath.Consequently, the trace alkane was successfully selectively concentrated and subsequently quantified in the concentration range from 1×10-9 volume fraction (1 ppbv) to 1×10-4 volume fraction (100 ppmv). The lowest limit of detection of hexane, which was estimated to be less than 0.5 ppbv by the condensation duration for 100 s, is expected to be substantially improved by the prolonged condensation.