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Enhancement of laser desorption ionization mass spectrometric signals of cesium iodide by elemental sulfur
Author(s) -
Kruegel Andrew,
Pavlov Julius,
Attygalle Athula B.
Publication year - 2013
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6510
Subject(s) - chemistry , ion , mass spectrometry , ionization , sulfur , mass spectrum , analytical chemistry (journal) , desorption , ion source , chromatography , organic chemistry , adsorption
RATIONALE The utility of elemental sulfur as a matrix for inorganic salts such as CsI, AgI, and KI was investigated because the conventional matrices deployed to generate gaseous ions from organic compounds, upon irradiation with a laser beam, are not suitable for inorganic salts. METHODS Sulfur and inorganic salts were admixed and irradiated with a 337‐nm UV laser. Laser desorption ionization (LDI) mass spectra were recorded in both positive and negative ion mode on a time‐of‐flight mass spectrometer. RESULTS The positive ion laser desorption ionization mass spectrum of CsI showed peaks at m/z 133, 393, etc. for [(CsI) n Cs] + ions. Similarly, negative ion spectra showed peaks at m/z 387, 647, etc. for [(CsI) n I] – ions. However, for n >2 ion clusters, the intensities of peaks were negligibly small in both ionization modes. In contrast, spectra recorded from CsI admixed with elemental sulfur showed peaks up to n = 13 for (CsI) n Cs + , and n = 9 for (CsI) n I – . A similar enhancement of ion abundances by sulfur was observed for the cluster ions generated from KI and AgI. CONCLUSIONS The dramatic increase in intensities of the higher‐mass CsI cluster peaks suggests that sulfur acts as a laser‐absorbing matrix for inorganic salts far superior to conventional matrices such as 2,5‐dihydroxybenzoic acid and α‐cyano‐4‐hydroxycinnamic acid. Copyright © 2013 John Wiley & Sons, Ltd.