Detection of volatile compounds correlated to human diseases through breath analysis with chemical sensors

The analysis of volatile compounds in the breath of humans was investigated by the application of different sensor principles. The detection of nitrogen oxide, an asthma marker, in breath at the low ppb-level (2–100 ppb) can be carried out by work function measurements. By the use of Cu–phthalocyanine dye as gas sensitive layer a calculated detection limit of 1.3 ppb is attainable. The low cross sensitivities to water and changes in the oxygen concentration are of great advantage for the use in breath analysis. With quartz microbalance (QMB) measurements acetone concentrations, a marker for diabetes, can be determined in the presence of ethanol and water vapor. The comparison of both sensor principles showed no correlation, hence, the combination can improve cross sensitivity and sensor selectivity.