Roadmap for fragmentation of protonated methylarginines in the gas phase

摘要: Abstract Up to MS4 collision-induced fragmentation study of protonated pseudomolecular ions l -arginine (Arg), ω-NG-monomethylarginine (MMA), ω-NG,NG-asymmetric dimethylarginine (aDMA) and ω-NG,NG′-symmetric (sDMA) were performed with Fourier transform ion cyclotron resonance mass spectrometry. The parent generated in a home-built atmospheric-pressure matrix-assisted laser desorption/ionization source, the admixing nitrocellulose matrix significantly reduced interfering peaks resulting spectra. While isobaric molecules (aDMA, sDMA) could be easily distinguished by low-order tandem spectrometry, was needed for unequivocal revelation some previously unreported pathways. Among total 44 fragment from two isomeric DMAs, 5 uniquely exclusively produced just one these precursor that allowed structures differentiated. unsurpassed advantage high resolution accuracy FTICR MS enabled us identify channels yield differing only ∼0.01 Da. sub-ppm accuracies facilitated proposing chemical all fragments observed. Many hitherto methylated arginines are observed first time.