Abstract: A Study on the FABMS of Muramyl Peptides and AnaloguesFu Guixiang;Yu Lu;Zhang Mingzhu; Xu Jiecheng (Shanghai Institiute of Organic Chemistry,Chinese Academy of Sciences, 354 Fenglin Lu,Shanghai 200032,China) Abstract:The fast atom bombardment mass spectra (FABMS) of five underivatized and seven derivatized muramyl peptides (MPs)were recorded. The protonated molecular ion, the sodium and potassium attachment ions of the muramyl peptides were appeared in the high mass range. Fragment ions corresponding to the loss of one molecule of water(for compounds 1-5)or one protected group (for compounds 6-12)from MH~+ were obtained. Sequential information was frequently observed. The entire lactyl peptide chain ions were formed in most FABMS of the title compounds. Keywords: muramyl peptide, lactyl peptide, FABMS