Department of Chemistry, Faculty of Science, Masaryk University, 625 00, Brno, Czech Republic.
Nenovision s. r. o., 612 00, Brno, Czech Republic.
J Am Soc Mass Spectrom. 2023 Apr 5;34(4):570-578. doi: 10.1021/jasms.2c00300. Epub 2023 Mar 14.
This study focuses on mapping the spatial distribution of Au nanoparticles (NPs) by laser desorption/ionization mass spectrometry imaging (LDI MSI). Laser interaction with NPs and associated phenomena, such as change of shape, melting, migration, and release of Au ions, are explored at the single particle level. Arrays of dried droplets containing low numbers of spatially segregated NPs were reproducibly prepared by automated drop-on-demand piezo-dispensing and analyzed by LDI MSI using an ultrahigh resolution orbital trapping instrument. To enhance the signal from NPs, an in source gas-phase chemical reaction of generated Au ions with xylene was employed. The developed technique allowed the detecting, chemical characterization, and mapping of the spatial distribution of Au NPs; the ion signals were detected from as low as ten 50 nm Au NPs on a pixel. Furthermore, the Au NP melting dynamics under laser irradiation was monitored by correlative atomic force microscopy (AFM) and scanning electron microscopy (SEM). AFM measurements of Au NPs before and after LDI MSI analysis revealed changes in NP shape from a sphere to a half-ellipsoid and total volume reduction of NPs down to 45% of their initial volume.
本研究通过激光解吸/电离质谱成像（LDI MSI）聚焦于金纳米粒子（Au NPs）的空间分布测绘。在单颗粒水平上，研究了激光与 NPs 的相互作用及相关现象，如形状变化、熔化、迁移和 Au 离子的释放。通过自动化按需分配压电分配，可重复性地制备包含低数量空间分离 NPs 的干燥液滴阵列，并通过使用超高分辨率轨道俘获仪器的 LDI MSI 进行分析。为了增强 NPs 的信号，采用了生成的 Au 离子与二甲苯在气相中的化学反应用于原位。所开发的技术允许检测、化学表征和 Au NPs 空间分布的测绘；从像素上的低至十个 50nm Au NPs 即可检测到离子信号。此外，通过相关原子力显微镜（AFM）和扫描电子显微镜（SEM）监测激光辐照下的 Au NP 熔化动力学。在 LDI MSI 分析之前和之后对 Au NPs 进行的 AFM 测量显示，NP 形状从球体变为半椭圆体，并且 NPs 的总体积减少到初始体积的 45%。
