Investigation of bombolitin complexes with mercury by liquid chromatography/tandem mass spectrometry

Solid-phase synthesis of (Cys)bombolitin peptide resulted in a crude reaction mixture containing the target peptide as well as a number of unknown products. The use of on-line liquid chromatography coupled to electrospray mass spectrometry (LC/ES-MS) gave a strong indication that these side-products were mainly complexes between the target peptide and mercury which was used in the form of mercury (II) acetate during the synthetic procedure. On-line LC/electrospray tandem mass spectrometry (ES-MS/MS) furnished reliable information on the amino acid sequences of both the target peptide and of the complexes with mercury or with mercury plus the b-mercaptoethanol used to eliminate the mercury at the end of the synthesis.# 1998 John Wiley & Sons, Ltd.