Ion mobility spectrometry coupled with multi-capillary columns for metabolic profiling of human breath

Recently, ion mobility spectrometry (IMS) started to be used for direct breath analysis with respect to metabolic profiling, biomarker finding and gas trace analysis. The present review describes the basic operation of an ion mobility spectrometer including the ionization process, humidity effects and sampling procedures. To enhance the resolution, pre-separation by multi-capillary columns (MCCs) is discussed and examples for IMS chromatograms are presented. The focus is to review the analytical method IMS with respect to potential use for direct investigations of humid air in direct breath analysis but not on detailed discussion of results of specific medical application of MCC/IMS or on specific analytes found in exhaled air.