Isotope pattern evaluation for the reduction of elemental compositions assigned to high-resolution mass spectral data from electrospray ionization fourier transform ion cyclotron resonance mass spectrometry

Abstract

The number of possible chemical formulae assigned to an accurate determined mass was significantly reduced by comparing spectral and theoretical isotope patterns based on mass measurement obtained with an ultrahigh-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (ESI-FTICR-MS) at high field intensity (7 T). Reduction is performed by rating congruency between experimental and theoretical pattern intensity and mass, and filtering out compositions with insufficient user-definable results. The methods used for isotope pattern simulation, peak searching, and comparison will be briefly described and evaluated on molecule ion signals of 25 compounds (300 -1000 Da) applying a mass accuracy of Ϯ5 ppm, a set of eight elements with constant constraints (C 0-200 H 0-1000 N 0-15 O 0-15 S 0-2 Cl 0-2 Br 0-2 Ru 0-1 ), natural isotope abundances and experimental resolution (full width at half

Compositional and structural studies of the oils from two edible seeds: Tiger nut, Cyperus esculentum, and asiato, Pachira insignis, from Ghana

“…The composition of intact TAGs and their regiochemistry were, in this work, studied by a high resolution mass spectrometric technique, ESI-FTICR-MS, and 13 C NMR, respectively. Table 4 shows the assignment of major mass peaks of TAG classes (Cx:n) (Stoll, Schmidt, & Thurow, 2006) in the positive ion ESI-FTICR mass spectra of oil samples from tiger nut and asiato seeds.…”

Spectral accuracy of molecular ions in an LTQ/Orbitrap mass spectrometer and implications for elemental composition determination

“…However, highresolution mass spectra also contain peak intensity information generated by the natural abundances of the various isotopes contained in the compound. This isotope information can be used to eliminate elemental compositions that despite an excellent match based on mass are not consistent with the observed isotope pattern [3]. Simple measurement of the relative intensities of the isotope peaks (M, M ϩ 1, M ϩ 2 .…”

Nutritional Metabolomics: What are the perspectives?

“…MS/MS strategies can be applied but there are still some issues, like lack of signal intensity or nonspecific losses. Stoll et al [26] have developed an identification strategy based on the isotope pattern evaluation to reduce the elemental compositions determined with a FTICR mass spectrometer. King et al [27] have also described a series of rules for chemical formula extraction and compound ranking from high resolution mass spectra.…”