Electrospray ionization mass spectra of amino acid phosphoramidates of adenosine

Amino acid phosphoramidates of adenosine were synthesized and determined by positive and negative ion electrospray ionization mass spectrometry (ESI-M S) in conjunction with tandem mass spectrometry (MS/MS). The fragmentation pathways were investigated. In the positive ion mass spectra abundant chara cteristic fragment ions appeared, and many complementary ions were found. I n the negative ion mass spectra only a few fragment ions were observed, and most of them contained phosphoryl groups. The results show that ESI-MS is a useful tool for structural determination of amino acid phosphoramidates o f nucleosides. Copyright (C) 2000 John Wiley & Sons, Ltd.