Design and performance of an instrument for soft landing of biomolecular ions on surfaces.
Design and performance of an instrument for soft landing of biomolecular ions on surfaces.
复制标题
用于生物分子离子在表面软着陆的仪器的设计和性能。
作者：
O. Hadjar;Peng Wang;J. Futrell;Yury Dessiaterik;Zihua Zhu;J. Cowin;M. Iedema;J. Laskin
设计并制作了一种新型离子沉积装置。我们的研究目标是研究生物分子与亲水和疏水表面的相互作用，并开展探索性实验，旨在高度选择性地在表面上沉积空间定义和独特选择的生物分子。该装置包括高透射电喷雾离子源、四极质量过滤器、使离子束偏转并防止源自离子源的中性分子撞击表面的弯曲四极杆、通过软着陆进行离子沉积的超高真空（UHV）室和用于在不破坏真空的情况下将表面引入UHV室的真空锁定系统。采用15 keV Ga+飞行时间二次离子质谱法和掠射红外反射吸收光谱法对大量选择的肽离子软着陆后的表面进行了非原位分析。结果表明，这两种技术是高度互补的方法，用于表征用一系列剂量的大量选择的生物分子离子制备的表面。我们还证明了肽离子在表面的软着陆可以用于控制制备已知覆盖范围的肽膜，用于SIMS中基质效应的基础研究。
A new ion deposition apparatus was designed and constructed in our laboratory. Our research objectives were to investigate interactions of biomolecules with hydrophilic and hydrophobic surfaces and to carry out exploratory experiments aimed at highly selective deposition of spatially defined and uniquely selected biological molecules on surfaces. The apparatus includes a high-transmission electrospray ion source, a quadrupole mass filter, a bending quadrupole that deflects the ion beam and prevents neutral molecules originating in the ion source from impacting the surface, an ultrahigh vacuum (UHV) chamber for ion deposition by soft landing, and a vacuum lock system for introducing surfaces into the UHV chamber without breaking vacuum. Ex situ analysis of surfaces following soft landing of mass-selected peptide ions was performed using 15 keV Ga+ time-of-flight secondary ion mass spectrometry and grazing incidence infrared reflection-absorption spectroscopy. It is shown that these two techniques are highly complementary methods for characterization of surfaces prepared with a range of doses of mass-selected biomolecular ions. We also demonstrated that soft landing of peptide ions on surfaces can be utilized for controlled preparation of peptide films of known coverage for fundamental studies of matrix effects in SIMS.