The Effects of Water Content and Additives on Ion Type in LDI-TOFMS Using Nanoparticle Matrices

摘要

We have described numerous solution preparation methods that affect ionization using AuNPs in LDI-TOFMS. Addition of acid, glycerol, and methanol, as well as changing the AuNP-toanalyte ratio results in enhancement of the [M + H]~(+) ion. Many of these preparation methods suggest that desorption/ionization is occurring from pre-formed ions. In order to further understand the ionization process, we have begun investigating the possibility of preformed ions using molecules with fixed charge sites. A molecule with a fixed charge should ionize as the molecular ion, M~(+(centre dot)) [6]. Preliminary results support this hypothesis, and further studies are currently under way.