Liquid chromatography and differential mobility spectrometry—data-independent mass spectrometry for comprehensive multidimensional separations in metabolomics

Abstract

The benefits of combining drift time ion mobility (DTIMS) with liquid chromatography–high-resolution mass spectrometry (HRMS) have been reported for metabolomics but the use of differential time mobility spectrometry (DMS) is less obvious due to the need for rapid scanning of the DMS cell. Drift DTIMS provides additional precursor ion selectivity and collisional cross-section information but the separation resolution between analytes remains cell- and component-dependent. With DMS, the addition of 2-propanol modifier can improve the selectivity but on cost of analyte MS response. In the present work, we investigate the liquid chromatography–mass spectrometry (LC–MS) analysis of a mix of 50 analytes, representative for urine and plasma metabolites, using scanning DMS with the single modifiers cyclohexane (Ch), toluene (Tol), acetonitrile (ACN), ethanol (EtOH), and 2-propanol (IPA), and a binary modifier mixture (cyclohexane/2-propanol) with emphasis on selectivity and signal sensitivity. 1.5% IPA in the N2 stream was found to suppress the signal of 50% of the analytes which could be partially recovered with the use of IPA to 0.05% as a Ch/IPA mixture. The potential to use the separation voltage/compensation voltage/modifier (SV/CoV/Mod) feature as an additional analyte identifier for qualitative analysis is also presented and applied to a data-independent LCxDMS-SWATH-MS workflow for the analysis of endogenous metabolites and drugs of abuse in human urine samples from traffic control. Graphical Abstract

Insights into modifiers effects in differential mobility spectrometry: A data science approach for metabolomics and peptidomics

“…In this subsection, we analyze our recent results 24 for a 50 analytes mixture (Figure S1 and Table 1), representative for urine and plasma metabolites, Figure 1. The data include respective LC retention time (RT) and CoV values for pure N 2 , 1.5% mole ratio of cyclohexane (Ch), ethanol (EtOH), isopropanol (IPA), toluene (Tol), acetonitrile (ACN), and one binary modifier: 0.05% mole ratio IPA in Ch.…”

“…A mix of 50 analytes, representative for urine and plasma metabolites (Figure S1 and Table S1), was analyzed by LC‐MS on a quadrupole time‐of‐flight (QTOF) mass spectrometer (TTOF 6600+, Sciex, Concord, ON, Canada) and was equipped with a differential ion mobility device (SelexION, Sciex). All details about chemicals, sample preparation, LC, DMS and MS experiments can be found in published work 24 …”

“…All details about chemicals, sample preparation, LC, DMS and MS experiments can be found in published work. 24…”

“…In this subsection, we analyze our recent results 24 for a 50 analytes mixture (Figure S1 and Table 1), representative for urine and plasma The utilization of a binary modifier is very closely related to one of the subjects of this manuscript-signal suppression with interacting modifiers. IPA of 1.5% is one of the most utilized modifiers due to its large CoV range (peak capacity).…”