Tim Causon

Modern ion mobility–mass spectrometry (IM–MS) is a key separation technology for detailed molecular characterization studies and also as part of emerging data acquisition strategies for demanding small molecule and several applications. Here is what you need to know.

In food analysis, many different biological matrices are investigated containing numerous compounds that can interfere with liquid chromatographyÐmass spectrometry (LC–MS) analysis. To overcome the challenges that arise with these highly complex matrices, the additional separation of analytes and matrix compounds complementing chromatographic separation is becoming more significant. In this article, the potential of IM-MS to increase selectivity and for additional identity confirmation is investigated. An extensive evaluation of IM-MS instruments was performed on a broad test set of food safety contaminants. The tested IM-MS platforms were DMS, TWIMS, low field DTIMS, and TIMS. CCS data were determined using the different instruments, and the ability to separate isomers and compounds of interest from sample matrix in the IM dimension was explored.

This article describes a workflow for the analysis of phenolic components in wine enabling confident differential analysis using high performance liquid chromatography (HPLC) in combination with low-field drift-tube ion mobility quadrupole time-of-flight mass spectrometry (IMS-QTOF-MS).

Here we propose an exemplary workflow for the analysis of phenolic extracts (i.e. wine) enabling confident differential analysis using high performance liquid chromatography in combination with low-field drift tube ion mobility quadrupole time-of-flight mass spectrometry (HPLC×IMS-QTOFMS). In this workflow, single-field collisional cross section values from low-field drift-tube IMS using nitrogen as drift gas (DTCCSN2) are readily extracted in addition to a retention time and a high resolution mass spectrum for each compound. “Alternating frames” experiments utilizing post-drift tube fragmentation also allow drift time-aligned MS/MS spectra to be obtained. Molecular feature extraction was highly repeatable with average precision values of 0.28% for retention time, 0.18% for drift time, and 1.5 ppm m/z determined for 233 molecular features found in all six technical replicates. The improved selectivity of this strategy increases confidence in intersample molecular feature alignment (i.e. compound identity confirmation), including the resolution of co-eluting isomeric compounds.