Spectroscopic determination of elemental composition of organic compounds with the aid of the X-PERT system

A methodology for establishing the molecular formula of an unknown organic compound is suggested. The methodology is based on the use of the expert system intended for the molecular structure elucidation from the molecular mass and 13C NMR, 1H NMR and IR spectra. For this purpose, X-PERT [Elyashberg et al., Anal. Chim. Acta 337 (1997) 265; 348 (1997) 443] system was employed in this paper. It was found that the system is capable of suggesting all possible molecular formulae from a given molecular mass and of rejecting the wrong ones. The screening of molecular formulae is carried out by the automatic verification of molecular structures generated on the basis of calculated molecular formulae. The structures are tested for conformity to the spectral data and additional criteria. It was found that the 13C NMR spectrometry can frequently be employed as an universal tool for determining both molecular and structural formulae of organic compounds.The approach is illustrated by a series of examples. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)