ESI ‐MS/MS analysis of protonated N‐methyl Amino Acids and their Immonium ions

In this study, theN‐methyl amino acids of all the amino acids (1‐21; including one isomeric pair) were synthesized and characterized by ESI ‐MS/MS, LC/MS/MS and HRMS. This data could be useful for detection and identification of N‐methyl amino acids in biological systems for future metabolomics studies. The MS/MS spectra of [M+H]+ ions of mostN‐methyl amino acids showed respective immonium ions by the loss of (H2O,CO). The other most common product ions detected were [MH ‐(NH2CH3]+, [MH ‐(RH)]+ (where R = side chain group) ions, and the selective structure indicative product ions due to side chain andN‐methyl group. The isomeric/isobaricN‐methyl amino acids could easily be differentiated by their distinct MS/MS spectra. Further, the MS/MS of immonium ions inferred side chain structure and methyl group on α‐nitrogen of the N‐methyl amino acids.

Source: Journal of Mass Spectrometry - August 13, 2019 Category: Chemistry Authors: Pavankumar P., Sudarshana Reddy B., Sai Sachin L., Nagarjuna Chary R., Prabhakar S. Tags: RESEARCH ARTICLE Source Type: research