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Species‐selectivity effects in the production of electrospray ions
Author(s) -
Hiraoka Kenzo,
Murata Konosuke,
Kudaka Ichiro
Publication year - 1993
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.1290070511
Subject(s) - chemistry , ion , electrospray , selectivity , analytical chemistry (journal) , ammonia , electrospray ionization , capillary action , mass spectrometry , chromatography , organic chemistry , catalysis , materials science , composite material
Positive‐ and negative‐ion production from electrosprayed charged liquid droplets has been studied. For acidified solutions of arginine, Arg‐Arg‐Arg, Lys‐Lys, and (CH 3 ) 4 NBr in methanol + water (80/20, v/v), the relative intensities of CH 3 OH 2 + ions were found to decrease faster than those of other sample ions as the distance ( d ) between the capillary tip and the interface plate was increased. The radial distribution of ion intensities in the spray cone was also examined. While the CH 3 OH 2 + ions and multiply charged ions had maximum intensities in the central region of the spray cone, NH 4 + and singly charged oligopeptide ions were found to be distributed in its peripheral region. The observed species‐selectivity effects in the production of electrospray ions were interpreted in terms of the volatility of ions in the charged liquid droplets. The negative‐ion intensities of the oligopeptide Glu‐Glu were enhanced greatly when ammonia was added to the solution. An optimum ammonia concentration which gives the strongest negative‐ion signals was ∼10 −4 M.