Quantitative observation of chemical reactions in solution by use of mass spectrometry.

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To observe directly some equilibrium reactions in solution such as ion association of di(trialkylammmonium)polymethylene salts in non-aqueous solution (case 1), dissociation of pH indicators (case 2), preparation and reduction of molybdophosphoric acid (case 3), the potentiality of electrospray ionization-mass spectrometry (ESI-MS) had been studied.At first, it became clear that the heat at desolvation plate in ESI module had driven the ion-association. And so, ESI-MS measurements were done without heating at desolvation plate for case 1 and case2. Next, to obtain the quantitative information for case1 and case2, the use of internal standards had been checked up. More adequate standard with comparable structure should be selected to obtaine more significant results, as ionization efficiency was influenced a great deal by the difference of salvation for each tonic species.Mass spoectra for 12-molybdophosphoric acid reduced in the presence of antimony showed that there were two or more species in solution, additionally liquid chromatography (LC) of their samples supported the presence of plural chemical species. In future, the composition and reducing equivalent of each species separated by LC will be become clear by the measurements of ESI-MS and flow-coulometry with column-electrode.