Recommendations for reporting ion mobility Mass Spectrometry measurements

Abstract

Here we present a guide to ion mobility mass spectrometry experiments, which covers both linear and nonlinear methods: what is measured, how the measurements are done, and how to report the results, including the uncertainties of mobility and collision cross section values. The guide aims to clarify some possibly confusing concepts, and the reporting recommendations should help researchers, authors and reviewers to contribute comprehensive reports, so that the ion mobility data can be reused more confidently. Starting from the concept of the definition of the measurand, we emphasize that (i) mobility values ( K 0 ) depend intrinsically on ion structure, the nature of the bath gas, temperature, and E / N ; (ii) ion mobility does not measure molecular surfaces directly, but collision cross section (CCS) values are derived from mobility values using a physical model; (iii) methods relying on calibration are empirical (and thus may provide method‐dependent results) only if the gas nature, temperature or E / N cannot match those of the primary method. Our analysis highlights the urgency of a community effort toward establishing primary standards and reference materials for ion mobility, and provides recommendations to do so. © 2019 The Authors. Mass Spectrometry Reviews Published by Wiley Periodicals, Inc.

Enhancing the Membranolytic Activity of Chenopodium quinoa Saponins by Fast Microwave Hydrolysis

“…RT stands for Retention Time in LC-MS experiments. CCS correspond to collision cross sections determined using traveling wave (TW) ion mobility with Nitrogen as the buffer gas and converted in CCS against Helium using a calibration procedure [31], namely TW CCS N2→He using the newly introduced nomenclature [33]. The Molar Proportion (% in the quinoa husk extract) and the mass fraction (mg•g −1 of the quinoa husk powder) of each saponin is estimated based on the ion signal ratios as determined by mass spectrometry experiments (LC-MS), with hederacoside C as an external standard.…”

Generation of a Collision Cross Section Library for Multi-Dimensional Plant Metabolomics Using UHPLC-Trapped Ion Mobility-MS/MS

“…CCS is a physical property of a compound measured using a specific drift gas, temperature and pressure. Thus, the ion mobility community has recently published recommendations for reporting ion mobility metadata [27] to help ensure that the many variables that influence K 0 and CCS measurements are reported. Trapped ion mobility spectrometry (TIMS; Figure 1) circumvents some of the previous challenges of IMS and offers higher resolutions of approximately 200 with much smaller instrumental size relative to drift tube IMS [28,29].…”

“…Calibration of the TIMS using a primary standard is a necessary and crucial step for accurate CCS determinations [27,29], and we typically use the Agilent ESI Low-concentration Tune Mix. Calibration was performed initially using CCS values provided within the Bruker software.…”

An Intrinsic Hydrophobicity Scale for Amino Acids and Its Application to Fluorinated Compounds

“…[15] Our study utilizes the gas-phase technique of ion mobility mass spectrometry (IM-MS), which separates ions according to their mass-to-charge ratio (m/z)a sw ell as their size and shape. [17] In this study, DT CCS He (CCS measured in He buffer gas using adrift tube instrument, [17] here denoted as W)isused to explore the relationship between the size of the amino acid cluster and the polarity of the side chain. [17] In this study, DT CCS He (CCS measured in He buffer gas using adrift tube instrument, [17] here denoted as W)isused to explore the relationship between the size of the amino acid cluster and the polarity of the side chain.…”