Structure verification of small molecules using mass spectrometry and NMR spectroscopy

The new complete molecular confidence (CMC) concept explores the synergies of the analytical techniques LC–MS and NMR to obtain an estimation of the purity, concentration, and identity of chemical compounds. The high mass accuracy of the MS and MS/MS data provided by the new generation of ESI-TOF and ESI-Q-TOF mass spectrometers provides an accurate determination of molecular weight, which is used specifically for the structural verification and purity determination of substances. The high separation of the isotope profile for both MS and MS/MS spectra affords further dimensions of information to achieve precise molecular formula determination. By performing a complete NMR spectral analysis, the automated consistency analysis routine provides a safe assessment of the consistency between molecular structure and 1 H NMR spectrum. The routine returns the fully assigned spectrum and the accurate NMR parameters extracted from the experimental data. Absolute quantification of a series of samples can be automatically performed including the whole workflow from sample setup, automatic NMR measurements, analysis, and spread-sheet reporting. This allows determining mass contents, relative amounts of substances, and purity. The strategy is explored on a set of 96 different pyrrole derivates. Graphical Abstract