Development of a high-energy collision-induced dissociation device for high-sensitivity and high-resolution MS/MS/MS

为了利用磁扇形质谱计建立高效率的MS/MS/MS，研制了一种可通过高压电源在几千伏电压下增强的碰撞池。该电池有1厘米深，被嵌入到新设计的离子源块中，以适应商业磁扇区质谱仪。根据单电荷质子化离子在10千伏电压下加速的离子透过率，对碰撞电池和位于电池后面的加速板(一对左右平板)施加的电压分别优化为3.0千伏和1.5千伏。根据前驱体离子的强度，这种设置允许近80%的离子透过率，并可以提供高能碰撞诱导解离所特有的产物离子。值得一提的是，离子捕获的效率和质量分辨率，特别是在质量以下。约20%的前驱体质量，已有很大改善。该装置利用磁性四扇形仪器，可以在低质量区从MS1中很难观察到的初级产物离子实现MS/MS/MS。它将有效地应用于生物大分子的结构分析。

In order to establish high-efficiency MS/MS/MS using a magnetic sector mass spectrometer, a collision cell, which can be potentiated at several kilovolts by high-voltage power supply, has been developed. The cell, which is 1 cm in depth, is embedded into the ion-source block which has been newly designed so as to fit with a commercial magnetic sector mass spectrometer. On the basis of ion transmittance of a singly-charged protonated ion accelerated at a 10-kV potential, the voltages applied to the collision cell and to the acceleration plates (a pair of right and left flat plates), which is situated just behind the cell, have been optimized to be 3.0 kV and 1.5 kV, respectively. This setting allowed almost 80% ion transmittance, based on the intensity of a precursor ion, and could provide the product ions specific for high-energy collision-induced dissociation. It is worth mentioning that the efficiency of ion acquisition and the mass resolution, especially, below the mass. of ca. 20% of a precursor mass, have been much improved. The present device could realize MS/MS/MS from a primary product ion, which has been hardly observed in MS1, in low-mass region, using a magnetic four-sector instrument. It will be efficiently applied for structural analysis of biomolecules.