Mass spectrometry of self-assembled monolayers: A new tool for molecular surface science

Most reactions can be performed in solution and on a surface, yet the challenges faced in applying known reactions or in developing entirely new reactions for modifying surfaces remain formidable. The products of many reactions performed in solution can be characterized in minutes, and even products having complex structures can be characterized in hours. When performed on surfaces, even the most basic reactions require a substantial effort-requiring several weeks-to characterize the yields and structures of the products. This contrast stems from the lack of convenient analytical tools that provide rapid information on the structures of molecules attached to a surface. This review describes recent work that has established mass spectrometry as a powerful method for developing and characterizing a broad range of chemical reactions of molecules attached to self-assembled monolayers of alkanethiolates on gold. The SAMDI-TOF mass spectrometry technique will enable a next generation of applications of molecularly defined surfaces to problems in chemistry and biology.