碰撞气体的种类和压力对离子阱质谱性能的影响

基于数字离子阱技术,研究了离子阱质谱分析实验过程使用的碰撞气体种类及压力对离子阱质谱性能,如质量分辨能力、信号强度、串级质谱分析,以及低质量截止效应等的影响.实验过程中,在离子的激发和碰撞诱导解离阶段,分别采用质量数不等的氦气(质量数=4 amu)、氮气(质量数=28 amu)、氩气(质量数=40 amu)等作为碰撞气体,以及不同的气体压力,研究了它们对质谱性能的影响.结果表明,当采用质量数较大的氩气作为碰撞气体时,可以有效改善低质量数截止效应和提高离子碰撞过程中的能量转移效率,同时提高离子捕获和解离效率,但是质量分辨率会明显降低.在获得较高质量分辨率方面,氦气作为碰撞气体时效果最好.在气压相同的情况下,质量数大的碰撞气体有利于提高串级质谱分析效率,即获得更多碎片离子峰和更多有关母体离子结构的信息.

Performance Investigation of Ion Trap with Various Collision gas and Pressures

Ion trap performances are investigated based on digital ion trap technique with different collision gases at different pressures. Collision gases of helium (4 amu), nitrogen (28 amu) and argon (40 amu) with various pressures are adopted in ion excitation and dissociation stages to investigate the ion trap performances, including mass resolution, signal intensity, tandem mass spectrometric analysis ability and low-mass cut off (LMCO) effect. It is found that when heavy gas of argon is used, energy can be efficiently transferred and LMCO effect is decreased with higher ion capture and dissociation efficiencies but with low mass resolution. Higher mass resolution is realized with helium as collision gas. Furthermore, at the same gas pressure, heavy gas is beneficial to abundant fragment ions and structural information of precursor ion.