Algorithm for Selecting Organic Compounds to Verify the Resolution of Electron Ionization Mass Spectrometers

The ion coalescence phenomenon complicates the evaluation of the effective resolution of Fourier-transform mass spectrometers. We propose an approach for confirming the resolution of an electron ionization Fourier-transform mass spectrometer using pairs of organic substances identified by automatically generated formula differences. The proposed method is compared with the search for organic substances in the National Institute of Standards and Technology (NIST) database. Under the given conditions of the mass spectrometer resolution range up to 45000-50000 at 100 <i>m/z</i>, 166 pairs of suitable compounds were found using the proposed method, while a search in the NIST database yielded only 88 pairs of compounds. This enabled the selection of six pairs of organic compounds that were most suitable for confirming the resolution of the high-resolution mass spectrometer using molecular ion peaks, and four pairs of compounds that allowed the resolution to be confirmed using fragment ion peaks. The resolution of the Fourier-transform mass spectrometer designed for gas analysis was experimentally evaluated by analyzing the spectra of a mixture of organic compounds selected using the proposed method.