No abstract

Non-covalent inclusion complexes formed between amino acids and derivatized calix [6]arenes are observed in MALDI mass spectrometry. The methyl, ethyl, and propyl ester derivatives of calix [6]arene yielded amino acid complexes, while the smaller calix[4]arene analogs did not. Similarly the underivatized calix[6]arene and calix[4]arene did not produce complexes. Amino acid complexes were observed for nearly all 20 amino acids in time-of-flight (TOF) analysis. In Fourier transform mass spectrometry (FTMS) analysis, however, only the most basic amino acids arginine, histidine, and lysine formed stable adducts. The complexes were abundant under matrix-assisted laser desorption ionization (MALDI) conditions, which suggested favorable interactions between host and guest. (J Am Soc Mass Spectrom 2002, 13, 964 -974)