Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MSIN K8-88, Richland, Washington 99352, USA.
Anal Chem. 2010 Jul 1;82(13):5718-27. doi: 10.1021/ac100734g.
An instrument has been designed and constructed that enables in situ reactivity and time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis of surfaces prepared or modified through soft and reactive landing of mass-selected polyatomic cations and anions. The apparatus employs an electrospray ion source coupled to a high transmission electrodynamic ion funnel, two focusing collision quadrupoles, a large 19 mm diameter quadrupole mass filter, and a quadrupole bender that deflects the ion beam, thereby preventing neutral contaminants from impinging on the deposition surface. The ion soft landing apparatus is coupled to a commercial TOF-SIMS instrument permitting the introduction of surfaces into vacuum and SIMS analysis before and after ion deposition without breaking vacuum. To facilitate a comparison of the current TOF-SIMS instrument with the in situ Fourier transform ion cyclotron resonance (FTICR-SIMS) deposition apparatus constructed previously, dications of the cyclic peptide Gramicidin S (GS) and the photoactive organonometallic complex ruthenium tris-bipyridine (Ru(bpy)(3)) were soft-landed onto fluorinated self-assembled monolayer (FSAM) on gold surfaces. In both cases, similarities and differences were observed in the secondary ion mass spectra, with the TOF-SIMS results, in general, characterized by greater sensitivity, larger dynamic range, less fragmentation, and fewer in-plume reactions than the corresponding FTICR-SIMS spectra. The charge reduction kinetics of both the doubly and singly protonated GS cations on the FSAM surface were also examined as was the influence of the primary gallium ion (Ga(+)) flux on the efficiency of these processes. In addition, we demonstrate that the new instrument enables detailed studies of the reactivity of catalytically active species immobilized by soft and reactive landing toward gaseous reagents.
设计并构建了一种仪器，可通过质量选择的多原子阳离子和阴离子的软反应性着陆原位反应性和飞行时间二次离子质谱（TOF-SIMS）分析表面。该仪器采用电喷雾离子源与高传输电动离子阱，两个聚焦碰撞四极杆，大直径 19mm 的四极质量滤波器和四极弯管耦合，四极弯管可以使离子束发生偏转，从而防止中性污染物撞击沉积表面。离子软着陆装置与商业 TOF-SIMS 仪器耦合，可在离子沉积前后在不破坏真空的情况下将表面引入真空并进行 SIMS 分析。为了方便将当前的 TOF-SIMS 仪器与先前构建的原位傅立叶变换离子回旋共振（FTICR-SIMS）沉积装置进行比较，将环肽 Gramicidin S（GS）的二价阳离子和光活性有机金属配合物钌三-联吡啶（Ru（bpy）（3））的二价阳离子软着陆到金表面上的氟化自组装单层（FSAM）上。在这两种情况下，都观察到二次离子质谱中的相似性和差异性，TOF-SIMS 的结果通常具有更高的灵敏度，更大的动态范围，更少的碎片和更少的 plume内反应，而对应的 FTICR-SIMS 光谱则相反。还研究了 FSAM 表面上双质子化和单质子化 GS 阳离子的电荷还原动力学，以及初级镓离子（Ga（+））通量对这些过程效率的影响。此外，我们证明了新仪器能够详细研究通过软反应性着陆固定的催化活性物质与气态试剂的反应性。
