Pinnick Veronica T, Verkhoturov Stanislav V, Kaledin Leonid, Bisrat Yordanos, Schweikert Emile A
Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA.
Anal Chem. 2009 Sep 15;81(18):7527-31. doi: 10.1021/ac9014337.
Secondary ion mass spectrometry (SIMS) run in the event-by-event bombardment/detection mode provides a unique ability to obtain molecular information from single nano-objects, since assays are based on secondary ion coemission from single impacts. The characterization of individual nano-objects is demonstrated with negatively charged polymer spheres that are attracted to and retained by nanoalumina whiskers. The whiskers, 2 nm in diameter and approximately 250 nm in length, are grafted to a microglass fiber with an average diameter of approximately 0.6 microm and several millimeters long. The spheres are monodisperse polystyrene nanoparticles (30 nm diameter). Massive Au projectiles, specifically 136 keV Au(400)(4+), were utilized to bombard analyte surfaces due to its high efficiency for producing multi-ion emission identified by time-of-flight mass spectrometry. Our results show that this mode of mass spectrometry can provide information on the nature, size, relative location, and abundance of nano-objects in the field of view. The key to characterizing nanodomains is to monitor the coincidental secondary ion emission from the nanovolume perturbed by single projectile impacts.
以逐事件轰击/检测模式运行的二次离子质谱（SIMS）具有独特的能力，能够从单个纳米物体中获取分子信息，因为分析是基于单次撞击产生的二次离子共发射。通过带负电荷的聚合物球体来展示单个纳米物体的表征，这些球体被纳米氧化铝晶须吸引并保留。晶须直径为2纳米，长度约为250纳米，接枝到平均直径约为0.6微米、长几毫米的微玻璃纤维上。球体是单分散的聚苯乙烯纳米颗粒（直径30纳米）。由于其在产生通过飞行时间质谱识别的多离子发射方面效率高，因此使用大量的金离子束，特别是136 keV的Au(400)(4+)来轰击分析物表面。我们的结果表明，这种质谱模式可以提供有关视野中纳米物体的性质、大小、相对位置和丰度的信息。表征纳米域的关键是监测由单个离子束撞击扰动的纳米体积中同时发生的二次离子发射。
