Evaluating the Use of Tricationic Reagents for the Detection of Doubly Charged Anions in the Positive Mode by ESI-MS

Abstract

The analysis of anions remains an important task for many areas of science, and new sensitive analytical methods continue to be of great interest. In this study, we present the use of 17 tricationic reagents for use as gas-phase ion pairing agents for divalent anions. When the anion pairs with the tricationic reagent, an overall positive charge is retained and enables detection by ESI-MS in the positive mode. The 17 tricationic reagents were made from 1 of 4 core structures and 7 terminal charged groups. The effect of these structural elements on the detection sensitivity of the complex is examined empirically. A comparison of signal-to-noise ratios achieved in positive and negative modes also is presented.

The evaluation and comparison of trigonal and linear tricationic ion-pairing reagents for the detection of anions in positive mode ESI-MS

“…The tricationic reagents used in this study were chosen to represent the best performing trigonal and linear trications used in previous studies [44,45]. These four tricationic reagents offer a variety of functional groups as well as differences in rigidity.…”

“…Before analysis, each trication was anion-exchanged to the fluoride form as previously reported [44].…”

“…Most recently, tricationic reagents were paired with divalent anions, which again could be detected as a singly charged complex [44,45]. The first group of tricationic reagents used as pairing agents were classified as trigonal trications [44].…”

“…The first group of tricationic reagents used as pairing agents were classified as trigonal trications [44]. These trications have fairly rigid structures and provided detection sensitivity enhancement for many of the anions tested.…”

Ionic Liquid Matrices for Mass Spectrometry: Design, Synthesis, and Applications

“…The use of ILs is a very rapidly developing area according to the number of publications that is growing almost exponentially over the last several years (Figure 1(b)). 6 ILs were applied for electrospray ionization mass spectrometry (ESI-MS) as ion-pairing reagent to detect anions in positive ion mode, 7 as solvent for liquid-liquid extraction, 8 as chromatographic stationary phases, 9 and as solvents in electrochemistry. 2 Chapters in the books and proceedings are also excellent sources for information about ILs.…”