Analytical Science Division, National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK.
J Am Soc Mass Spectrom. 2019 Feb;30(2):309-320. doi: 10.1007/s13361-018-2086-8. Epub 2018 Oct 23.
Sets of matrix factors, Ξ, are reported for the first time for secondary ions in secondary ion mass spectrometry for several binary organic systems. These show the interplay of the effects of ion velocity, fragment chemistry, and the secondary ion point of origin. Matrix factors are reported for negative ions for Irganox 1010 with FMOC or Irganox 1098 and, for both positive and negative ions, with Ir(ppy)2(acac). For Irganox 1010/FMOC, the Ξ values for Irganox 1010 fall with m/z, whereas those for FMOC rise. For m/z < 250, Ξ scales very approximately with (m/z), supporting a dependence on the ion velocity at low mass. Low-mass ions generally have low matrix factors but |Ξ| may still exceed 0.5 for m/z < 50. Analysis of ion sequences with addition or loss of a hydrogen atom shows that the Ξ values for Irganox 1010 and FMOC ions change by - 0.026 and 0.24 per hydrogen atom, respectively, arising from the changing charge transfer rate constant. This effect adds to that of velocity and may be associated with the nine times more hydrogen atoms in the Irganox 1010 molecule than in FMOC. For Irganox 1098/Irganox 1010, the molecular similarity leads to small |Ξ|, except for the pseudo molecular ions where the behavior follows Irganox 1010/FMOC. For Ir(ppy)2(acac)/Irganox 1010, the positive secondary ions show twice the matrix effects of negative ions. These data provide the first overall assessment of matrix factors in organic mixtures necessary for improved understanding for quantification and the precise localization of species. Graphical Abstract ᅟ.
首次报道了二次离子质谱中几种二元有机体系中次级离子的矩阵因子 Ξ。这些结果显示了离子速度、碎片化学和次级离子原点的相互作用。报道了 Irganox 1010 与 FMOC 或 Irganox 1098 的负离子，以及 Ir(ppy)2(acac)的正离子和负离子的矩阵因子。对于 Irganox 1010/FMOC，Irganox 1010 的 Ξ 值随 m/z 降低，而 FMOC 的 Ξ 值升高。对于 m/z < 250，Ξ 非常近似地与 (m/z) 成正比，支持在低质量时依赖于离子速度。低质量离子通常具有较低的矩阵因子，但 |Ξ| 仍可能超过 0.5，对于 m/z < 50。对添加或失去一个氢原子的离子序列进行分析表明，Irganox 1010 和 FMOC 离子的 Ξ 值分别变化-0.026 和 0.24 每氢原子，这是由于电荷转移速率常数的变化。这种效应增加了速度的影响，并且可能与 Irganox 1010 分子中比 FMOC 多九倍的氢原子有关。对于 Irganox 1098/Irganox 1010，分子相似性导致 Ξ 值较小，除了准分子离子外，其行为遵循 Irganox 1010/FMOC。对于 Ir(ppy)2(acac)/Irganox 1010，正次级离子的矩阵效应是负离子的两倍。这些数据为有机混合物中矩阵因子的整体评估提供了首次必要的信息，有助于提高对定量和物种精确定位的理解。
