Jiang Jichun, Hua Lei, Xie Yuanyuan, Cao Yixue, Wen Yuxuan, Chen Ping, Li Haiyang
Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian, Liaoning 116023, People's Republic of China.
University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, People's Republic of China.
J Am Soc Mass Spectrom. 2021 May 5;32(5):1196-1204. doi: 10.1021/jasms.1c00016. Epub 2021 Apr 20.
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is popular because of its advantages of parallel / detection and less damage for unknown or rare samples compared to sector field instruments. However, the mass resolving power of conventional TOF-SIMS is limited by its relatively large energy spread and primary ion pulse width. In this work, a high mass resolution multireflection time-of-flight secondary ion mass spectrometer (MR-TOF-SIMS) was designed and constructed. Compared with conventional TOF-SIMS, the ion flight path of the MR-TOF-SIMS was extended from meters to subkilometers, and the mass resolving power reached to 87000 after an 80 cycles flight. A pair of symmetrically arranged ion orthogonal injection/ejection deflectors, which could eliminate the influence of fringing field and remove ions with a large energy spread, were proposed to further improve the mass resolving power in fewer flight cycles. A zircon standard sample sputtered by a 10 keV O beam was used to demonstrate the performance of the MR-TOF-SIMS instrument. As a result, the mass resolving power was up to 30000 only after 22 flight cycles. The Zr peak was significantly separated from the mass interference peaks of ZrH, ZrH, CCH, and CH. The mass accuracies of Zr ions and their hydrides were better than 1.2 ppm. An ion transmission efficiency over 40% was achieved after 115 cycles.
飞行时间二次离子质谱仪(TOF-SIMS)因其具有并行检测的优势,且与扇形磁场仪器相比,对未知或稀有样品的损伤较小,故而颇受欢迎。然而,传统TOF-SIMS的质量分辨率受其相对较大的能量分散和一次离子脉冲宽度的限制。在本工作中,设计并构建了一台高质量分辨率多反射飞行时间二次离子质谱仪(MR-TOF-SIMS)。与传统TOF-SIMS相比,MR-TOF-SIMS的离子飞行路径从米级扩展到了亚千米级,经过80次循环飞行后,质量分辨率达到了87000。提出了一对对称排列的离子正交注入/引出偏转器,其可消除边缘场的影响并去除能量分散较大的离子,以在更少的飞行循环次数下进一步提高质量分辨率。使用由10 keV O束溅射的锆标准样品来演示MR-TOF-SIMS仪器的性能。结果,仅经过22次飞行循环后,质量分辨率就高达30000。Zr峰与ZrH、ZrH、CCH和CH的质量干扰峰明显分离。Zr离子及其氢化物的质量准确度优于1.2 ppm。经过115次循环后,离子传输效率达到了40%以上。