Evaluation of drift gas selection in complex sample analyses using a high performance drift tube ion mobility-QTOF mass spectrometer

Abstract

A recently developed uniform-field high resolution ion mobility (IM) quadrupole time of flight (Q-TOF) mass spectrometer is used for evaluating the utility of alternate drift gases for complex sample analyses. This study provides collision cross section comparison for 275 total pesticides including structural isomers in nitrogen, helium, carbon dioxide, nitrous oxide and sulfur hexafluoride drift gases. Furthermore, a set of small molecules and Agilent tune mix compounds were used to study the trends in experimentally derived collision cross section values in argon and the alternate drift gases. Two isomeric trisaccharides, melezitose and raffinose, were used to evaluate the effect of the drift gasses for mobility separation. The hybrid ion mobility Q-TOF mass analyzer used in this study consists of a low pressure uniform field drift tube apparatus coupled to a high resolution Q-TOF mass spectrometer. Conventionally, low pressure ion mobility instruments are operated using helium drift gas to obtain optimal structural information and collision cross-section (CCS) values that compare to theoretical CCS values. The instrument employed in this study uses nitrogen as the standard drift gas but also allows the utility of alternate drift gases for improved structural analysis and selectivity under certain conditions. The use of alternate drift gases with a wide range of polarizabilities allows the evaluation of mobility separation power in terms of induced dipole interactions between the drift gas and the analyte ions.

Separation of biologically relevant isomers on an Orbitrap mass spectrometer using high‐resolution drift tube ion mobility and varied drift gas mixtures

“…Changing to a more polar drift gas is expected to affect the drift separation of molecules that are polarizable . As this may impact the mobility of two molecules differently, the net separation can be increased or decreased (or remain unchanged) when introducing a more polar drift gas.…”

“…Furthermore, since neither pumping speed nor gas‐specific pressure sensor calibration need to be considered, one can easily switch between different drift gasses enabling optimization of compound separation based on polarity differences, as will be demonstrated here. Changing the separation by changing the drift gas is a known method for altering separation . AP‐DTIMS also has flexibility in the temperature ranges.…”

Ion Mobility Collision Cross Section Compendium

“…79 Recent studies which explicitly report CCS values in alternative drift gases include measurements of ammonium in helium, nitrogen, argon and carbon dioxide from Viehland and coworkers, 80 the combined DTIMS and TWIMS study from Barran and coworkers investigating myoglobin in helium, nitrogen, argon, and neon, 81 DMA measurements of CCS in air from both de la Mora and coworkers 82 and Hogan and coworkers, 83 and DTIMS work from Fjeldsted and coworkers exploring the CCS differences of pesticides in a variety of drift gases including helium, nitrogen, carbon dioxide, nitrous oxide, argon, and sulfur hexafluoride. 84 …”

Drift tube ion mobility and four‐dimensional molecular feature extraction enable data‐independent tandem mass spectrometric ‘omics’ analysis without quadrupole selection

“…In addition, IM‐MS provided CCSs of the peptides for identification. CCSs of all the identified peptides were automatically measured using the “single electric field CCS calculation” method . Comparison with a peptide database or predicted CCSs from theoretical calculations will greatly improve the identification confidence of peptides.…”