Naylor S, Lamb J H
MRC Toxicology Unit, Carshalton, Surrey, UK.
Rapid Commun Mass Spectrom. 1990 Jul;4(7):251-5. doi: 10.1002/rcm.1290040706.
Experimental variables affecting the daughter-ion spectra of a series of protonated peptides [MH]+, produced by fast-atom bombardment ionization, using a low energy (0-450 eV) quadrupole collision cell are investigated. The parameters studied include target gas pressure, collision energy, cross-sectional area and acidity of the target gas. The results show that low-mass immonium ions are preferentially formed both at high collision energies (greater than 200 eV) and at target gas pressures greater than 10(-6) mBar (where multiple collisions occur in the gas cell). Positive fragment ion abundance is maximized when acidic gases are used as the target gases, and this is rationalized on the basis of a proton-transfer reaction from the target gas to the amide nitrogen of the peptide bond promoting fragmentation.
研究了一系列通过快速原子轰击电离产生的质子化肽[MH]+的子离子光谱的实验变量，该过程使用低能量（0 - 450 eV）四极杆碰撞池。研究的参数包括靶气压力、碰撞能量、靶气的截面积和酸度。结果表明，在高碰撞能量（大于200 eV）以及靶气压力大于10^(-6)毫巴（气体池中发生多次碰撞）时，优先形成低质量的亚胺离子。当使用酸性气体作为靶气时，正碎片离子丰度最大，这是基于从靶气到肽键酰胺氮的质子转移反应促进碎片化来解释的。
