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| Format: | Artículo científico |
| Language: | en |
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Sociedade Brasileira de Física
2005
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| Online Access: | https://www.redalyc.org/articulo.oa?id=46435113 |
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Table of Contents:
- Mechanism of Insulin Emission in Matrix Assisted Laser Ionization F. Fernández-Lima V. M. Collado C. R. Ponciano L. S. Farenzena E. Pedrero E. F. da Silveira Física, Astronomía y Matemáticas In the present paper the emission of intact insulin quasi-molecular ion [M+H]+ during laser ablation (MALDI)is studied. It was observed in particular that the insulin TOF molecular peak increases as the laser powerincreases. The DE-Vestal method for the initial velocity measurements was improved theoretically includingthe distance (d0) until the free expansion regime can be considered. According to the present analysis, the v0parameter given by the DE-Vestal method is interpreted as the initial velocity that the desorbed ion would haveif no collision occurs in the plasma. The improved method interprets v0 as the final initial velocity, i.e., asthe velocity that the desorbed ions have when the plasma free expansion starts and, effectively, collisions nolonger occur. The new method allows also the determination of d0, the distance to the solid when the freeexpansion starts. The data fitting shows that the distance (d0) has a linear dependence on the lasers intensity.Extrapolation of these values gives I = 0.69 G W cm¡2 as the minimum energy density necessary to producehigh density plasma during the insulin ions desorption when using ®CHCA matrix. 2005 artículo científico 0103-9733 https://www.redalyc.org/articulo.oa?id=46435113 en http://www.redalyc.org/revista.oa?id=464 Brazilian Journal of Physics application/pdf Sociedade Brasileira de Física Brazilian Journal of Physics (Brasil) Num.1 Vol.35