Black silicon as matrix-free laser desorption ionization substrate

ANYL 111

Yong Chen, yongchen@gwu.edu, Department of Chemistry, George Washington University, 725 21st Street N.W, Washington, DC 20052 and Akos Vertes, vertes@gwu.edu, Department of Chemistry, Institute for Proteomics Technology and Applications, George Washington University, 725 21-st Street, N.W, Washington, DC 20052.
A silicon-based substrate was developed as a matrix-free laser desorption ionization surface. When low-resistivity wafers were processed with a mode-locked Nd-YAG laser in air, SF6 gas, or water environment, regularly arranged conical microspikes formed on the silicon surface. The radii of the spike tips varied with the processing environment, ranging from about 500 nm in water, to 2 μm in SF6 gas, and to 5 μm in air. The surfaces were cleaned with HF to remove SiO2, rinsed with deionized water, and air dried. Mass spectra induced by a nitrogen laser showed the formation of protonated ions of angiotensin I (1296 Da), substance P (1347.6 Da), and insulin (5733.5 Da) from the processed Si surfaces but not from the unprocessed areas. Threshold fluences for desorption/ionization were comparable to those used in matrix-assisted laser desorption/ionization (MALDI).
 

General Papers
7:00 PM-9:00 PM, Sunday, 28 August 2005 Washington DC Convention Center -- Hall A, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 29 August 2005 Washington DC Convention Center -- Hall A, Sci-Mix

Division of Analytical Chemistry

The 230th ACS National Meeting, in Washington, DC, Aug 28-Sept 1, 2005