Emission of M2X+ cluster ions in thermal ionization mass spectrometry in the presence of graphite.
The emission of M2X+ cluster ions in thermal ionization mass spectrometry when graphite is loaded on the heating filaments was studied. The emission model of non-reductive thermal ionization of graphite was preliminarily discussed and factors influencing the thermal emission of M2X+ ions were investigated. The results show that the intensities of M2X+ cluster ions are related to ionic radius and crystal lattice energy, and possibly also to the solvation energies of ions. The intensities of M2Cl+ (M stands for K, Rb, and Cs) cluster ions, the M2Cl+/M+ ratios, and the 37Cl/35Cl ratios determined from M2Cl+ ion measurement usually increase with measurement time. The variation of the 37Cl/35Cl ratios determined from Cs2Cl+ ion measurement is lower than those based on K2Cl+ and Rb2Cl+ ion measurement, indicating the lowest isotopic fractionation.
Xiao
Y K
YK
Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, China. qhyhyjs@public.xn.qh.cn
Wei
H Z
HZ
Liu
W G
WG
Wang
Q Z
QZ
Zhou
Y M
YM
Wang
Y H
YH
Lu
H
H