Combinatorial Chemistry Using Mass Spectrometry and SALI

As part of its ongoing program in combinatorial chemistry, SRI is developing new mass spectrometric analytical tools for characterizing both the surface and bulk composition of new materials as well as gas phase reaction products. Surface analysis tools are based on SRI's patented Surface Analysis by Laser Ionization (SALI) technique. Combinatorially generated solid-phase samples are examined by stimulated desorption of neutral species followed by nonselective laser photoionization and time-of-flight mass spectrometry. The desorption can be performed using rare gas ions, electrons, an additional laser beam, or programmed thermal desorption.

SALI provides a unique combination of sensitivity with quantitation for chemical composition measurements. It can achieve submicron lateral resolution and depth resolution of several angstroms and therefore can be used to precisely determine surface, interface, and bulk compositions.

For certain applications, such as testing of combinatorially produced catalysts, more conventional gas-phase electron-impact mass spectrometry is used to characterize reaction products and their yield. Highly automated rapid screening tools are being developed to maximize throughput.
 

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Technical Contact:
Michael J. Coggiola
(650) 859-3045
michael.coggiola@sri.com