ANYL 110 |
| We are developing a two-laser matrix-assisted laser desorption/ionization technique to study fundamental processes of MALDI as well as improve ionization efficiency. The technique involves irradiating the MALDI target with two sub-threshold laser pulses of different wavelengths with an adjustable time delay. The IR laser is a wavelength tunable optical parametric oscillator (OPO) running at 2.94 μm, and the UV laser is a 337 nm N2 laser. Both lasers are attenuated to fluences at which no signal can be observed from either laser alone. A variety of MALDI matrices were analyzed as well as peptide and protein standards. Delay times for optimum UV MALDI ionization efficiency were found to be between 10 and 100 ns after the IR pulse. A thermal model is proposed where IR heating of the sample surface allows UV ionization at fluences below room temperature threshold. |
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General Papers
7:00 PM-9:00 PM, Sunday, 28 August 2005 Washington DC Convention Center -- Hall A, Poster
Sci-Mix
Division of Analytical Chemistry |