Stochastic dynamic electrospray ionization mass spectrometric diffusion parameters and 3D structural analysis of coordination species of copper(II) ion with glycylhomopentapeptide and its dimeric associates

Abstract

The kernel idea for this paper came from our more recent development of a mass spectrometric model equation, based on stochastic dynamics. It treats quantitatively the experimental intensity of analytes and their fragment ions under soft ionization conditions. The effort has resulted to exact universally applicable and empirically testable relationship, between mass spectrometric stochastic dynamic diffusion and the intensity. A linear correlation at high level of statistical significance occurs between DSD and the corresponding quantum chemical diffusions, obtained within the Arrhenius' approximation. It provides bridge between experimental MS parameters and 3D structure of analyte ions. Furthermore, we have claimed that the total intensity of the ions is proportional to their DSD parameter according to our model equation; or Itot ~ DSD. As evident from the small–scale of our contributions, so far, the simplistic theoretical concept and corresponding model equation need to be translated into a broad practical employment, because of; there is extended the capability of mass spectrometry beyond its routine application as irreplaceable method for quantitative analysis to the analytical practice. The superior features of the mass spectrometric instrumentation can offer us a new perspective of looking at the implementation of the method to exact 3D structural analysis in condense phase. As far as any such statement should be strongly quantified from the point of view of the chemometrics, this work deals with application of our stochastic dynamic concept of mass spectrometric diffusion to structural analysis of complex ions of CuII–ion with glycylhomopentapeptide and its dimeric associates. The large difference in the coordination fashion of oligopeptides, and competitive fragment paths together with the variety of the coordination modes of CuII–ion; and accounting, in parallel, for the different oxidation states of copper allows for us to demonstrate the great capability of our theoretical concept, studying so challenging research area. The experimental design is based on high resolution electrospray ionization mass spectrometric data in positive operation mode. High accuracy ab initio and methods based on theory on functional of density are used. Both static and molecular dynamic methods are employed.