Conversion of Ca2+ salt of an organic compound to its Li+ salt to simplify the fast atom bombardment mass spectrum.
The FAB mass spectrum of the Ca(2+) salt of RK-682 (1, MW 368), a potent protein tyrosine phosphatase inhibitor, shows a complex pattern due to Ca(2+) adduct ions with multimers of 1 and their decomposition ions. Addition of LiCl greatly simplified the FAB mass spectrum, providing a prominent Li(+) adduct ion of 1 at m/z 381 [M+2Li-H](+). The addition of LiCl also greatly simplified the FAB mass spectrum of calcium pantothenate. This approach may be generally useful for molecular weight determination of multivalent metal salts of organic compounds, or organic compounds that can form Li salts, by FAB mass spectrometry.
Morisaki
Naoko
N
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan. hashimot@iam.u-tokyo.ac.jp
Kobayashi
Hisayoshi
H
Nagasawa
Kazuo
K
Baba
Yoshiyasu
Y
Sodeoka
Mikiko
M
Hashimoto
Yuichi
Y
D002118:Calcium / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry; D008094:Lithium / Q000737:chemistry*; D008970:Molecular Weight; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors* / Q000737:chemistry*; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors; D016339:Spectrometry, Mass, Fast Atom Bombardment
D004791:Enzyme Inhibitors; C094097:RK 682; D008094:Lithium; D010749:Phosphoprotein Phosphatases; D017027:Protein Tyrosine Phosphatases; D002118:Calcium