Selecting and identifying gas-phase protonation isomers of nicotineH⁺ using combined laser, ion mobility and mass spectrometry techniques

Abstract

Protonation isomers of gas-phase nicotineH+ are separated and assigned using a combination of FAIMS and UV photodissociation action spectroscopy.

Electrostatically Tuning the Photodissociation of the Irgacure 2959 Photoinitiator in the Gas Phase by Cation Binding

“…The methods used for photodissociation action spectroscopy are described in detail elsewhere. 1,2 Following Julian and co-workers, 3 a commercial, linear quadrupole ion trap mass spectrometer (Thermo Fisher Scientific LTQ VELOS) has been coupled with a tunable Nd:YAG optical parametric oscillator laser (EKSPLA). Following electrospray ionisation (ESI), populations of either one Irg molecule bound to a single metal mono-cation (Irg-M Q+ ) or two Irg molecules bound to a single metal di-cation (Irg-M Q+ -Irg) were isolated and stored in the ion trap and then irradiated by a single laser pulse, which is directed through the long axis of the ion trap via a quartz window mounted at the rear of the mass spectrometer chamber.…”

“…The Evert values of Structure A for each ion agree well with the Eexp values with a systematic overestimation of ~0.5 eV which is typical of TD-DFT. 2,15,16 Although Additional Gaussian functions for higher energy transitions are shown (red line) along with the sum of Gaussians (grey line). Green sticks are the calculated transition energies (Evert) for each lowest energy structure using SCS-CC2/def2-TZVP.…”

Collision-assisted stripping for determination of microsolvation-dependent protonation sites in hydrated clusters by cryogenic ion trap infrared spectroscopy: the case of benzocaineH+(H2O)n

“…14,15 This solvent-dependent protonation-site switching is not only found in BC but prevails in other (bio-)organic molecules. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Much effort has been devoted to microsolvated clusters, in which an ion is solvated by a few to several hundreds of molecules, 14,[34][35][36] because the degree of solvation can be tuned by controlling the type and numbers of solvent molecules.…”

Roadmap on dynamics of molecules and clusters in the gas phase

“…Several research groups have coupled IMS techniques with tunable light sources to enable isomer-selected action spectroscopy. Implementations include IMS coupled with photoelectron spectroscopy [265,266], photodissociation spectroscopy [267][268][269][270][271][272], and photoisomerization spectroscopy [273]. A recent example of isomer-specific IR action spectroscopy is shown in Fig.…”

“…Currently, isomer-specific action spectroscopy instrumentation is either built by specialist research groups [265,266,273], or is based on modified commercial mass spectrometers [268,271,272]. General availability of a well-characterized IMS device, such as SLIM-IMS with ion trapping capacity, which could be easily integrated into new or existing instrument, would be a decisive step in setting isomer-selected action spectroscopy as the standard.…”