Supplemental infrared (IR) activation was applied to reduce background chemical noise and increase analyte ion signal in a linear ion trap mass spectrometer. Peptides, proteins, and small molecules were all introduced by electrospray ionization, and when regions of chemical noise were isolated and subjected to IR irradiation, protonated analyte molecules were observed in the product ion mass spectra. By isolating the entire mass range (e.g., m/z 400–2000) and then irradiating all ions in the trap, supplemental IR activation increased the signal of singly protonated peptides by almost 70% and by 40%–55% for the lower charge states of cytochrome c. This increase in analyte ion signal was less dramatic for the higher charge states of peptides and proteins. The chemical noise present in the mass spectra is attributed to incomplete desolvation of the electrospray, as the abundance of the protonated peptides observed upon supplemental IR activation of the chemical noise decreased with higher inlet capillary temperatures. Collision activation was not as effective for desolvating the ions present in the chemical noise.

应用补充红外 (IR) 激活以减少背景化学噪声并增加线性离子阱质谱仪中的分析物离子信号。肽、蛋白质和小分子都是通过电喷雾电离引入的，当化学噪声区域被隔离并受到 IR 照射时，在产物离子质谱图中观察到质子化的分析物分子。通过隔离整个质量范围（例如m/z 400–2000），然后照射阱中的所有离子，补充 IR 激活将单质子化肽的信号增加了近 70%，对于较低电荷增加了 40%–55%细胞色素c 的状态. 对于肽和蛋白质的较高电荷状态，分析物离子信号的这种增加不那么显着。质谱中存在的化学噪声归因于电喷雾的不完全去溶剂化，因为在化学噪声的补充 IR 激活时观察到的质子化肽的丰度随着入口毛细管温度的升高而降低。碰撞激活对于化学噪声中存在的离子的去溶剂化不是那么有效。