共 44 条
Laser desorption ionization of gramicidin S on thin silver films with matrix isolation in surface plasmon resonance excitation
被引:7
作者:
Owega, S
[1
]
Lai, EPC
[1
]
Mullett, WM
[1
]
机构:
[1] Carleton Univ, Ottawa Carleton Chem Inst, Dept Chem, Ottawa, ON K1S 5B6, Canada
基金:
加拿大自然科学与工程研究理事会;
关键词:
laser desorption ionization;
time-of-flight mass spectrometry;
matrix isolation;
surface plasmon resonance;
silver film substrate;
chemical ionization;
electronic excitation mechanism;
D O I:
10.1016/S1010-6030(98)00397-9
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
Laser desorption ionization (LDI)/laser ablation (LA) time-of-flight mass spectrometry (TOFMS) studies are performed via back-illumination on thin silver films deposited with gramicidin S, a cyclic decapeptide (1141 Da). Experimental results indicate an electronic excitation mechanism at low laser fluences and a thermal process at high laser fluences. In a perpendicular orientation of the thin silver film with respect to the drift tube axis, better success of chemical ionization (CI) of neutral silver atoms/clusters and gramicidin S molecules by Ag+ monomer cations within the ablation plume is evident. When these LDI/LA studies are repeated under surface plasmon resonance (SPR) conditions, the neutral atoms/clusters/molecules undergo SPR LDI/LA via a different laser energy transfer process compared to direct LDI/LA. These results also indicate an electronic excitation mechanism, only with a lower laser fluence requirement. Upon addition of a matrix, 2,5-dihydroxybenzoic acid (DHB), CI of gramicidin S molecules by Agi monomer cations is hindered while the CI of gramicidin S molecules by Na+ cations can occur at an even lower laser fluence. Thus, SPR LDI/LA with matrix isolation is an excellent technique for the mass analysis of gramicidin S. (C) 1998 Elsevier Science S.A. All rights reserved.
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页码:123 / 135
页数:13
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