Exemplar application of multi-capillary column ion mobility spectrometry for biological and medical purpose

Abstract

In recent years, ion mobility spectrometry is increasingly in demand for new applications especially on biological samples (cells, bacteria, fungi), in medicine (diagnosis, therapy and medication control e.g. from breath analyses), for food quality control, safety monitoring and characterisation or process control in chemical and pharmaceutical industry. For this purpose instruments based on gas phase separation of ions in weak electric fields were developed at ISAS-Institute for Analytical Sciences, focussing on the particular challenges such as humid and rather complex samples, specific sampling procedures adapted to the application, fast pre-separation techniques like multi-capillary columns and suitable data processing including data bases for relevant analytes and automatic characterisation of IMS-chromatograms. Feasibility studies were carried out successfully for biological and medical purpose at ISAS, including the detection of bacteria, fungi and metabolites of cells and in human breath. For all those samples characteristic pattern of analytes were found and could be used for the identification of cell lines, fungi and bacteria as well as of numerous diseases. Furthermore, the quantification of those analytes could be used to obtain information about the state of the process or person (e.g. growth of cultures, development of diseases, level of medication, grade of cancer). Those examples shall demonstrate the potential of ion mobility spectrometry for the selected applications. However, a general and reliable data bases of reference analytes is required in the near future to enable an exploitation of the metabolic pathways and to confirm the relevance of the detected signals for the investigated topic.

Peak finding and referencing in MCC/IMS-data

“…For details see [41]. Details considering the MCC/IMS are summarised in [38]. Temperature and pressure fluctuations in the drift tube and alignment of spectra are considered in [42].…”

“…Figure 1 shows a cut-out of a typical IMS-Chromatogram of an air sample simulating human breath (for experimental details see [30][31][32]38]). Normally, a visualisation is realised by clicking into the 2D-plot in window A to get the corresponding single spectrum in window B for rather visual inspection.…”

Visualisation of MCC/IMS-data

“…a human breath analysis using an ion mobility spectrometer equipped with a Multi-CapillaryColumn (MCC) should be considered. The resulting data set consists of a set of parameters describing the whole measurement and experimental setup and of a set of single spectra at different retention times-for further experimental details see ref [35][36][37][38][39][40][41][42][43]. The origin of the data could be DMS, FAIMS or other IMS-it is only essential to have such structured information available.…”

Assessment of the Feasibility of the Use of Conductive Polymers in the Fabrication of Ion Mobility Spectrometers

“…Thermogravimetric assessment combined with headspace analysis by ion mobility spectrometry and gas chromatography-mass spectrometry indicated that Zeonex TM encapsulated carbon-loaded nylon could be used to fabricate a snaptogether injection molded stacked ring drift tube, 4.25 cm long that could be substituted for a conventional wire-wound heated ceramic drift tube of the same length into a high temperature ion mobility spectrometer. 3,4 ; food quality and environmental 5 screening applications 6,7 . Another vitally important aspect of IMS is the continuing development of IMS-MS systems and applications, and a recent review provides a useful and informed overview of this area 8 .…”