A simple desalting procedure for fast atom bombardment mass spectrometry

A simple and efficient procedure for desalting samples prior to fast atom bombardment mass spectrometry utilizes low-pressure reverse-phase chromatography with disposable high-capacity mini-columns. Microscale (0.1-10 mumol) sample purification with high analyte recovery is possible for nucleosides, nucleotides and peptides. Salt removal has been evaluated both by conductivity and mass spectral methods and is greater than 99% for the model compounds cytidine, adenosine and AMP, even when they are contaminated with a 10 molar excess of NaCl. This procedure is also applicable to a range of small peptides as demonstrated with pyro-Glu-His-Gly and methionine enkephalin.