title: Detailed study on the use of electrospray mass spectrometry to investigate speciation in concentrated silicate solutions.
abstract: Silicate speciation in aqueous solutions containing tetraalkylammonium hydroxide as template is examined by electrospray mass spectrometry. A thorough study has been carried out to define and optimize the conditions of analysis for a highly concentrated reaction solution of inorganic species--in this case, silicate oligomers--by using different ion source designs. The results reveal specific advantages with respect to the detected species. Condensation of monomers leads to oligomeric units that condense further in different reaction steps to larger species. Potential gas-phase reactions that can disturb characterization of the formed silicate species were intensively investigated and characterized. One reaction that plays a key role is the alkoxylation of Si-OH groups that is caused by two different reactions: first, a reaction of methanolate from the solvent and, second, by the involvement of the template salt, tetramethylammonium hydroxide.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim, Germany.
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Pelster
authors.forename: Ferdi
authors.initials: F
authors.lastname: Schüth
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schrader