Combining energy‐dependent electrospray ionisation with tandem mass spectrometry for the analysis of inorganic compounds

Abstract

The recently developed technique of energy-dependent electrospray ionisation mass spectrometry (EDESI-MS) has been implemented on a triple quadrupole mass spectrometer such that fragmentation occurs in the collision cell rather than at the skimmer cone. This modification enables a superior two-dimensional map of the collision voltage versus mass-to-charge ratio to be generated, providing unambiguous peak assignments. This latest enhancement to the technique is referred to as energy-dependent electrospray ionisation tandem mass spectrometry (EDESI-MS/MS). In the present work the technique has been applied to investigate the sequential removal of ligands from the inorganic mixed-metal anionic cluster compound [Ru 5 EXPERIMENTALAll mass spectra were collected using a Micromass Quattro LC instrument, in negative-ion mode, with methanol as the mobile phase. The nebuliser tip was set at 3100 V and 90°C, and nitrogen was used as the bath gas. Samples were introduced directly into the source at 4 mLmin À1 via a syringe pump. Data collection was carried out in continuum mode. For the EDESI mass spectrum, the cone voltage was initially set at 0 V. A scan time of 7 s per spectrum and a low resolution setting (peak width at half-height $0.8 Da) were used to maximise the signal-to-noise ratio. The cone voltage was manually increased by increments of 1 V after every scan up to a maximum of 200 V. A full scan from 0±200 V therefore took approximately 25 min to collect. The EDESI-MS/MS spectrum was collected by selecting the m/z 1024.5

Insights into the Post‐Translational Methylation of Arginine from Studies of Guanidinium–Water Nanodroplets

“…EDESI-MS is a method of collecting and visualizing collections of data from collision-induced dissociation (CID) experiments. [14][15][16][17] Similar CID studies have been performed on metal-centered water clusters to probe solvation, fragmentation pathways, and solvent coordination chemistry. [18,19] Herein, we used EDESI-MS to observe the loss of water molecules from nanodroplets of water that contained different methylated guanidinium ions.…”

A Hypothetical Model for the Formation of Transition Metal Carbonyl Clusters Based upon 4n Series Skeletal Numbers

“…The corresponding cluster k values of the fragment should be on the increase. Very interesting extensive work on the metal carbonyls that involves stripping off the CO ligands has been done by several research groups (Butcher, et al, 2002(Butcher, et al, , 2003Crawford, et al, 2006;Critchley, et al, 1999;Dyson, et al, 2001;Henderson, et al, 1998Henderson, et al, , 2009 Table 7). Although the series and the skeletal numbers predict that each of the Re skeletal atoms except one should have a hydrogen atom, the structural determination indicates all the hydrogen atoms are bridging (Miessler, et al, 2014) as observed in borane clusters.…”

Practical approaches to the ESI-MS analysis of catalytic reactions

“…Parsing all this CID data from product ion MS/MS spectra (the classic experiment for determining unknowns: select a particular ion in the first mass analyzer, fragment it in a collision cell and analyze the fragments in the second mass analyzer) is not trivial, not least because there is so much of it. Faced with the prospect of arbitrarily keeping some of the data and discarding the rest, we instead chose to keep all of it and display it in an alternative fashion: as a 3D surface, where m/z ratio and fragmentation energy (cone/collision voltage) are two of the axes, and ion intensity the third, an approach we call ‘energy‐dependent ESI‐MS’ . An example is shown in Fig.…”