Detection and Identification of Cations and Anions of Ionic Liquids by Means of Electrospray Ionization Mass Spectrometry and Tandem Mass Spectrometry

Abstract

Electrospray ionization (ESI) and collision-induced dissociation (CID) spectra of nine ionic liquids have been measured. The main fragmentations of most of these ionic liquid cations were due to the loss of a butene molecule. In contrast to tetraalkylammonium ions, CID spectra of aromatic cations may represent insufficient information for unambiguous identification due to their only partial fragmentation. CID spectra of ionic liquid anions, however, allowed their reliable recognition, since isomers/isobars of such inorganic species are rare. Detection limits of cations and anions in a mixture of different ionic liquids seemed to depend on their surface activity as determined by the hydrophobicity of these species.

Molecular ions of ionic liquids in the gas phase

“…Which of these series is observed is solely determined by the polarity of the extraction voltage. Such observations were made by fast atom bombardment (FAB) [13], laser desorption/ionization (LDI) [14], matrix-assisted laser desorption/ ionization (MALDI) [14 -16], electrospray ionization (ESI) [17][18][19][20], and field desorption (FD) [21]. However, none of these ionization methods delivered the ionized ion pair, the "molecular ion" CA ϩ• , of an IL that would yield further support for the ionization mechanism shown in Scheme 1.…”

Ionic Liquids Matrices for Laser Assisted Desorption/Ionization Mass Spectrometry

“…Understand the ionic liquids properties are very important and further characterization are highly required. The characterization of these materials may take place using different analytical tools included ultraviolet-visible absorption (UV-vis absorption), Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR) and mass spectrometry included fast atom bombardment mass spectrometry (FAB-MS), laser desorption/ionization mass spectrometry (LDI-MS), matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS), and field desorption mass spectrometry (FD-MS) [49][50][51][52]. These techniques are useful and may be used in the future to monitor the synthesis procedure [48].…”

“…The analyses of complicated samples were reported. For instance, analysis of a complex lipid mixture (i.e., a raw extract of a milk sample) using ILs showed high S/N ratio, reduced chemical noise and limited formation of matrix-clusters [50]. The reports showed mainly dual function for ILMs, i.e., solvent for extraction and matrices.…”

“…Ionic liquids matrices have higher stability for storage and under vacuum [80,89]. They offered homogeneous spots that improved the reproducibility of laser shots-shots and decreased the time consuming [50]. The ion-pairing charge of ionic liquids implies strong interaction with the analytes [90].…”

Study of Imidazolium And Pyrrolidinium Ionic Liquids By Ion Mobility Spectrometry And Electrospray Ionization Mass Spectrometry

“…[3] Electrospray ionization mass spectrometry (ESI-MS) is recognized as a suitable technique for the study of ILs. It has been used for the direct detection of intact ions of both undiluted and dissolved ILs, [4][5][6] and for investigating their decomposition and fragmentation pathways. [7][8][9] Conversely, ion mobility spectrometry (IMS) [10] has been rarely utilized for investigations of ILs.…”