Investigation of 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide under Bi_n^x+ cluster ion bombardment

Abstract

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to study 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide under Bi-ion and Bi-cluster-ion (Bi 2 -7 + , Bi 3,5,7 ++ ) bombardment in positive and negative polarity. Peak pattern as well as practical experiences with the bismuth cluster LMIG is discussed. Mass spectra with the best mass resolution were obtained using Bi 3 ++ or Bi 5 ++ as primary ion source. The secondary ion yield of high molecular ion is enhanced up to two orders of magnitude upon changing from ion to cluster ion bombardment.

Investigation of ionic liquids under Bi‐ion and Bi‐cluster ions bombardment by ToF‐SIMS

“…The primary ion current was directly measured using a Faraday cup detector located on a grounded sample holder (for Bi 1 + , Bi 2 + , Bi 3 + and Bi 3 2+ ) or was determined indirectly via extrapolation of target current measurements with adequate variation of pulse width at a given cycle time, usually 20 µs (for Bi 4 + , Bi 5 + , Bi 6 + , Bi 7 + and Bi 5 2+ ). [20,21] The difference between the measured ion currents was at maximum ±5% which is in good agreement to previously published data. [20,22,23] and a primary ion energy of 25 keV for single charged ion clusters and 50 keV for double charged ion clusters.…”

“…The vacuum in the analysis chamber was kept in the range of 10 −8 mbar and 10 −9 mbar during all measurements. The mass scale was calibrated using a number of well defined and easily assignable secondary ions; [21] …”

Zwitterionic clusters with dianion core produced by electrospray ionisation of Brønsted acidic ionic liquids

“…The occurrence of such clusters is not restricted to ESI and is observed also with other ionisation methods. [31][32][33] Also, this type of cluster ion is not unique to the ILs, it is in fact commonly observed for ionic, salt-like species and there have been earlier studies by this group on non-IL cluster ions of this type. [34][35][36] In tandem mass spectrometry experiments a cluster ion of choice is separated from others and allowed to dissociate.…”