The benefits of gas cluster beams for use in organic SIMS is now well established – high-mass clusters are highly efficient at sputtering organic and polymeric materials, producing intact molecular and high-mass fragment ions. Until now, however, spatial resolution of these beams was limited to several microns. Incorporated onto the J105 SIMS, the GCIB SM focuses a 70 keV beam of gas clusters—up to CO2 (10k)—into a spot as small as 1 μm, revealing even more from your samples.
High-resolution Gas Cluster SIMS. (left) Total SIMS image of a pine-needle cross section obtained on the J105 SIMS at 1.5 μm per pixel, running a 50 kV CO2(5k)+ beam. (right) SIMS mage of untreated hippocampus tissue with various masses overlaid: blue = GM1 (1572.9 m/z), yellow = GM1 (1544.8 m/z), green = ST (806.5 m/z), taken at 2 μm per pixel with a 30 kV CO2(3k)+ beam. Data courtesy of Dr Hua Tian, Pennsylvania State University.
Cluster beams, where the energy per nucleon is quite low, are extremely effective at sputtering soft materials such as organic tissue and polymers. Unlike polyatomic beams such as Bi3+ or Au3+, which cause significant fragmentation of organic molecules both in the surface and sub-surface regions, gas cluster beams produce very little fragmentation, and cause almost no sub-surface damage, enabling depth profiling through organic tissue without loss of fidelity.
Single Cell Depth Profiling. Overlay image showing lipid (cyan) and adenine (magenta) signals inside individual HeLa cells, taken at 1 μm per pixel with a 50 keV CO2(5k)+ beam on the J105 SIMS. This image was taken as part of a series during which the top surface of the cells was gradually ethced away, revealing the nuclear material within. Data courtesy of Dr Hua Tian, Pennsylvania State University.
Combining high-spatial resolution with low-damage sputtering of organics, the GCIB SM provides users unparalleled access to details previously hidden within their samples, or which required multiple techniques to reveal. This latest advancement in gas cluster beam technology bridges the gap between conventional SIMS technology—high spatial resolution, destructive—and other imaging MS techniques such as MALDI (matrix assisted laser desorption ionization) and DESI (desorption electrospray ionization)—low spatial-resolution, non-destructive.
Resolving Power. Secondary electron image of a metallic mesh obtained using a 70 keV CO2(8k) beam, showing 1 μm spot size. Data courtesy of Dr Hua Tian, Pennsylvania State University.
