Relationships between chemical mass shifts and physiochemical properties of ions are sought by examining substituted acetophenones, benzophenones, and pyridines in a modified ion trap mass spectrometer. Systematic changes in chemical mass shift occur with changes in substituent in the acetophenones and the benzophenones. Brown's sigma+ constant, which is a measure of electronic effects of substituents in reactions that involve positive charge development, is shown to correlate linearly with chemical mass shifts in para-substituted acetophenones and benzophenones. Brown's sigma+ constant also correlates with the ease of dissociation of the ions via a correlation with ionization energy. It is suggested that ease of dissociation is the underlying factor in determining chemical mass shifts. The experimental results also suggest that dissociative collisions between ions and buffer gas make a much greater contribution to chemical mass shifts than do elastic collisions.

中文翻译：

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对取代的苯乙酮和二苯甲酮的化学质量位移与布朗的sigma常数的相关性。

通过在改良的离子阱质谱仪中检查取代的苯乙酮，二苯甲酮和吡啶，可以寻找离子的化学质量变化与物理化学性质之间的关系。随着苯乙酮和二苯甲酮中取代基的变化，发生化学质量转移的系统变化。布朗的sigma +常数（是涉及正电荷发展的反应中取代基的电子效应的度量）显示与对位取代的苯乙酮和二苯甲酮的化学质量变化线性相关。布朗的sigma +常数还通过与电离能的相关性与离子离解的难易程度相关。建议解离的容易性是确定化学物质移动的根本因素。