Metal Ion Chemistry of Amino Acids in Gas-Phase

• Main Authors: Mey Tso, 左梅
• Other Authors: Chien-Chung Liou
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/71728100272978925115

碩士 === 東海大學 === 化學系 === 93 === Abstract Triple-stage quadrupole tandem mass spectrometry and fast ion bombardment technique were applied for study of ion-molecular reaction, the complex formation, and fragmentation pattern of amino acids with metal ions in the gas phase. Results of our collisionally activated dissociation (CAD) experiment indicate that protonated amino acids (A＋H)+ can lose specific neutral molecules (HCOOH, H2O and NH3) or dissociate the amino acid’s backbones to produce their daughter fragment ions. In addition, the CAD spectra of amino acids with alkali metal ions (A＋Na)+ and (A＋K)+ show the dissociation of the amino acid’s backbones, while those spectra of amino acids with (A＋Rb)+ and (A＋Cs)+ show the dissociation of the whole amino acids to form Rb+ or Cs+ without the cleavage of their backbones. The difference in the binding abilities of amino acids with alkali metal ions are determined by the metal ion’s radius, charge density and electrostatic force. Finally, the complex-ion formations of amino acids with alkaline-earth metal ions are in the form of deprotonation, (A－H＋M)+ and their dissociation pathways involve the dissociation of the amino acids backbones.