In the negative-ion mode, the structural isomers MMA and SA are indistinguishable from each other (Fig.
To support the hypothesis that positive-ion formation takes place through a resonance of keto-enol equilibrium within the part of the MMA molecule between the two carboxyl groups, we evaluated, along with other acids, fragmentation of n-butyl diesters of two other structural isomers dicarboxylic acids, DiMMA and EMA acids (Fig.
For structural isomers
, we use the nomenclature defined by Benskin et al.
We developed a new approach that enables a quantitative prediction of the architecture of linear, branched, and cyclic self-assembled nanostructures, their aggregation numbers and size distribution, and the formation of structural isomers
that coelute); in such cases, Fourier-transform infrared spectroscopy can be used, even though it does not have the same inherent sensitivity as MS in the selected ion monitoring mode.