Fourier transform ion cyclotron resonance mass spectra

Stenson, A. C., Marshall, A. G., and Cooper, W.T. (2003). Exact masses and chemical formulas of individual Suwannee River fulvic acids from ultrahigh resolution electrospray ionization fourier transform ion cyclotron resonance mass spectra. Anal. Chem. 75,1275-1284. 

Table 3.1. Chemical formulas from exact masses in electrospray ionization Fourier-transform ion cyclotron resonance mass spectra (adapted from Fievre etal., 1997).

Fig. 3.12. Series of electrospray ionization Fourier-transform ion cyclotron resonance mass spectra obtained in a two-dimensional mass spectrometry experiment. Proceeding from top to bottom (a) full mass spectrum of a fulvic acid mixture (b) stored waveform inverse Fourier transform (SWIFT) waveform ejection from the ion cyclotron resonance cell of ions of all but a narrow m/z range (c) the resulting isolated parent ion mass spectrum and (d) the product ion mass spectra produced by collision-induced dissociation. Reprinted from Fievre etal. (1997) with permission from the American Chemical Society.

Resolution Electrospray Fourier Transform-Ion Cyclotron Resonance Mass Spectra. Int. J. Mass Spectrom. 2005, 246, 1-9. 

Fig. 11.14 Tetrahenzoxazines (/f)-3 and (S)-3 and tetrakis-aminomethylated Fesoicinarene (S)-17. Quaternary ammonium ions (18). Isotope pattern regions of the ESI-PTlCR (FTICR Fourier transform ion cyclotron resonance) mass spectra of (S)-17 with pseudo-racemates of the two guests. The bottom row represents control experiments with a reversed labelling of the two guest enantiomers as compared to the top row [35] (Image reproduced frinn [35] with permission from Springer)...

In analyses where molecular masses are being matched, more accurate mass measurements provide more reliable matches and identifications.26,65,66 In a reference laboratory the mass accuracy to several decimal points, provided by a Fourier transform ion cyclotron resonance mass analyzer, may be desirable. In field or portable systems there is usually a trade-off in mass accuracy for size and ruggedness. Reliable identifications can be made with moderate mass accuracy, even 1 Da, if a large enough suite of molecular ions is recorded and used to search the database. If both positive ion and negative ion spectra are... 

The highest-resolution mass spectra are obtained by Fourier transform ion cyclotron resonance mass spectrometry.34 Molecular ions of two peptides (chains of seven amino acids) differing in mass by 0.000 45 Da were separated with a 10% valley between them. The ions each have a mass of 906.49 Da and a width at half-height of 0.000 27 Da. Compute the resolving power by the 10% valley formula and by the half-width formula. Compare the difference in mass of these two compounds with the mass of an electron. 

Thus the interpretation of ESI-MS spectra of POPAM dendrimers recorded on an FT-ICR (Fourier-Transform Ion Cyclotron Resonance) mass spectrometer leads to drastic overestimation of defects in the sample molecules (Fig. 7.4). The... 

The negative ion mass spectra of 21 was studied by an electron im-pact/Fourier transform ion cyclotron resonance mass spectrometry method (95MI13). 

Hogan, J. D. and Laude, D. A. J., "Mass Discrimination in Laser Desorption/ Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Cation-Attachment Spectra of Polymers," Anal. Chem., 64, 763-769, 1992. 

All mass spectra were obtained with a Fourier transform ion cyclotron resonance mass spectrometer (FTMS). The theory and applications of FTMS spectrometry are well-established and will not be discussed here. In our apparatus the sample was located at one of the trap plates of the cell, inside a superconducting magnet. Two pulsed lasers were used, one for tire PFPE desorption and another for metal ion formation. Typically, 2 to 4 mj/pulse of 248 nm or 193-nm light (20 ns fwhm) from an excimer laser was softly focused to an elliptical spot with a 2-mm long axis for desorption. To create the metal ions, a 0.3-mJ pulse of 532-nm light (10 ns fwhm) from the doubled output of a Nd YAG was tightly focused. The metal substrates were prepared from foils of various metals (typically 0.010 in. tiiick). Surface preparation was not critical because the experiment was not sensitive to PFPE/metal surface interactions since the thickness of the polymer films was on the order of 1 pm. 

VaUe, J.J. Eyler, J.R. Oomens, J. Moore, D.T. van der Meer, A.F.G. von Helden, G. Meijer, G. Hendrickson, C.L. Marshall, A.G. Blakney, G.T. Free electron laser-Fourier transform ion cyclotron resonance mass spectrometry facility for obtaining infrared multiphoton dissociation spectra of gaseous ions. Rev. Sci. Instrum. 2005, 76.023103. 

Figure 1 Comparison of parts of the SORI-CAD ESI FT-ICR mass spectra of the [M + 3 H] + precursor ions of (A) nisin A (wild-type nisin), (B) nisin S5A, (C) nisin H27 K, and (D) nisin I30W-H, showing the region containing doubly charged fragment ions. The ions in the transgenic variants that are shifted in mass compared to nisin A are marked with asterisks. (Reprinted from Lavanant H, Heck A, Derrick PJ, et al. (1998) Characterization of genetically modified nisin molecules by Fourier transform ion cyclotron resonance mass spectrometry. European IVIass Spectrometry 4-. 405-416, with permission IM Publications.)...

A wide variety of other MS techniques are used to detect explosives. Two notable techniques are Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and CE-MS. FT-ICR-MS is used to probe pseudomolecular ion formation of RDX, PETN, and TNT using several ionization sources including EDI, El, electron capture ionization (EC), and chemical ionization (Cl). Analyses are performed both in the positive and negative ionization mode, and identities are assigned to the major pseudomolecular ion peaks seen in the spectra from each explosive [198]. TTie composition of several explosive compounds from postblast residue is assessed with FT-ICR-MS by identifying the explosive and inactive ingredients in a smokeless powder, TNT,... 

All films were free from cracks and defects and thick enough for laser desorption ionization-Fourier transform ion cyclotron resonance-mass spectrometry (LDI-FTICR-MS) spectra to be rid of the silicon signal (Si-H at mass-to-charge ratio [m/z] = 28). 

To check the identity and purity of the products obtained in the above reactions it is not sufficient to analyze for the sulfur content since a mixture may incidentally have the same S content. Either X-ray diffraction on single crystals or Raman spectra of powder-like or crystalline samples will help to identify the anion(s) present in the product. However, the most convincing information comes from laser desorption Fourier transform ion cyclotron resonance (FTICR) mass spectra in the negative ion mode (LD mass spectra). It has been demonstrated that pure samples of K2S3 and K2S5 show peaks originating from S radical anions which are of the same size as the dianions in the particular sample no fragment ions of this type were observed [28]. 

The most common types of MS/MS instruments available to researchers in food chemistry include triple quadrupole mass spectrometers and ion traps. Less common but commercially produced tandem mass spectrometers include magnetic sector instruments, Fourier transform ion cyclotron resonance (FTICR) mass spectrometers, and quadrupole time-of-flight (QTOF) hybrid instruments (Table A.3A.1). Beginning in 2001, TOF-TOF tandem mass spectrometers became available from instrument manufacturers. These instruments have the potential to deliver high-resolution tandem mass spectra with high speed and should be compatible with the chip-based chromatography systems now under development. 

Fornarini, Matire, and co-workers110 have recently used Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry assaying the multiphoton dissociation behavior (IR-MPD) of the C3H7+ ion. This study has confirmed the conclusions of the computational results discussed above. The IR spectra recorded in solution and in a solid matrix display close resemblance to the spectral characteristics found by the IR-MPD study. Theoretical studies also indicated that the virtually free methyl rotation allows the interconversion of the two enantiomers of the isopropyl cation. 

Figure 23 Schematic representation of inductively coupled plasma Fourier transform ion cyclotron resonance (ICP-FT-ICR) mass spectrometer used to obtain spectra shown in Figs. 9.21 and 9.22.

Ion-molecular reactions are used to resolve isobaric interferences, as discussed, in ICP-MS with a collision/reaction cell or by utilizing ion traps. The mass spectra of Sr, Y and Zr (Fig. 6.10a) without O2 admitted into the collision cell and (Fig. 6.10b) with 10 Pa Oj are different. By introducing oxygen, selective formation of YO and ZrO, but not SrO, is observed. This behaviour of different oxide formation is relevant for an interference free determination of Sr. Ultrahigh mass resolving power ICP mass spectrometry (at m/Am 260 000) selectively removes unwanted ions prior to transfer to the FTICR analyzer cell by gas-phase chemical reactions, e.g., for separation of Ca from " Ar+ obtained with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer equipped with a 3 tesla superconducting magnet. ... 

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