A metabolomic investigation of key cellular processes relating to cancer development and progression.

Recent advancements in mass spectrometry have facilitated new analytical approaches capable of comprehensively characterizing metabolites in biological samples. Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) combines excellent mass accuracy (pp

Position-sensitive ion detection in precision Penning trap mass spectrometry

A commercial, position-sensitive ion detector was used for the first time for the time-of-flight ion-cyclotron resonance detection technique in Penning trap mass spectrometry. In this work, the characteristics of the detector and its implementation in a Penning trap mass spectrometer will be presented. In addition, simulations and experimental studies concerning the observation of ions ejected from a Penning trap are described. This will allow for a precise monitoring of the state of ion motion in the trap.Comment: 20 pages, 13 figure

FOURIER TRANSFORM- ION CYCLOTRON MASS RESONANCE SPECTROSCOPY

Mass spectrometry is essentially a technique for "weighing" molecules. Mass spectrometry is based upon the motion of a charged particle, called an ion, in an electric or magnetic field. Mass spectrometry relies on the formation of gas-phase ions (positively or negatively charged) that can be isolated electrically (or magnetically) based on their mass-to-charge ratio ( m/z ). Where as in Fourier transform ion cyclotron mass resonance spectroscopy(FTICR-MS) the m/z ratio measurement of an ion is based upon the ion's motion or cyclotron frequency in a magnetic field. Ions are detected by passing near detection plates and thus differently from other mass detectors/analysers in which ions are hitting a detector (at different times or places),The ions are trapped in a magnetic field combined with electric field perpendicular to each other (Penning trap). They are excited to perform a cyclotron motion. The cyclotron frequency depends on the ratio of electric charge to mass (m/z) and strength of the magnetic field.This spectrometric analysis can provide important information about the analytes, including their structure, purity, and composition

Fourier transform ion cyclotron resonance study of ion-molecule reactions of [M - OCH 3] + ions of methyl 2,3,4,6-tetra-O-methyl-d-hexopyranosides with ammonia

Kovácik V, Hirsch J, Thölmann D, Grützmacher H-F. Fourier transform ion cyclotron resonance study of ion-molecule reactions of [M - OCH 3] + ions of methyl 2,3,4,6-tetra-O-methyl-d-hexopyranosides with ammonia. Organic Mass Spectrometry. 1991;26(12):1085-1088.Glycosidic oxocarbenium ions A1+ were formed by isobutane chemical ionization from methyl 2,3,4,6-tetra-O-methyl-beta-D-mannopyranoside, methyl 2,3,4,6-tetra-O-methyl-beta-D-galactopyranoside and methyl 2,3,4,6-tetra-O-methyl-beta-D-glucopyranoside (the ring -O-being converted into -O+=), and their reaction with ammonia was studied by Fourier transform ion cyclotron resonance spectrometry. Very slow formation (reaction efficiency 0.6-1.4%) of the adduct ion [A1 + NH3]+ was observed as the main process for carefully thermalized ions A1+. Interestingly, the efficiency of the adduct ion formation depends on the sterochemistry of ions A1+

Radiocarbon positive-ion mass spectrometry

Proof-of-principle of a new mass spectrometric technique for radiocarbon measurement is demonstrated. Interfering nitrogen and hydrocarbon molecules are largely eliminated in a charge-exchange cell operating on non-metallic gas. The positive-to-negative ion conversion is the reverse of that conventionally used in accelerator mass spectrometry (AMS) and is compatible with plasma ion sources that may be significantly more efficient and capable of greater output than are AMS sputter ion sources. The Nanogan electron cyclotron resonance (ECR) ion source employed exhibited no sample memory and the >50 kyrs age range of AMS was reproduced. A bespoke prototype new instrument is now required to optimise the plasma and cell physics and to realise hypothetical performance gains over AMS

Selective parent ion axialization for improved efficiency of collision-induced dissociation in laser desorption-ionization Fourier transform ion cyclotron resonance mass spectrometry

AbstractWe have systematically established the excitation frequency, amplitude, duration, and buffer gas pressure for optimal axialization efficiency and mass selectivity of quadrupolar excitation-collisional cooling for isolation of parent ions for collision-induced dissociation in Fourier transform ion cyclotron resonance mass spectrometry. For example, at high quadrupolar excitation amplitude, ion axialization efficiency and selectivity are optimal when the applied quadrupolar excitation frequency is lower than the unperturbed ion cyclotron frequency by up to several hundred hertz. Moreover, at high buffer gas pressure (10−6 Torr), quadrupolar excitation duration can be quite short because of efficient collisional cooling of the cyclotron motion produced by magnetron-to-cyclotron conversion. Efficiency, detected signal magnitude, and mass resolving power for collision-induced dissociation (CID) product ions are significantly enhanced by prior parent ion axilization. With this method, we use argon CID to show that C+94 (m/z 1128) formed by Nd:YAG laser desorption-ionization behaves as a closed-cage structure

Characterization of Polyphosphoesters by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

FT-ICR mass spectrometry, together with collision-induced dissociation and electron capture dissociation, has been used to characterize the polyphosphoester poly[1,4-bis(hydroxyethyl)terephthalate-alt-ethyloxyphosphate] and its degradation products. Three degradation pathways were elucidated: hydrolysis of the phosphate–[1,4-bis(hydroxyethyl)terephthalate]bonds; hydrolysis of the phosphate–ethoxy bonds; and hydrolysis of the ethyl–terephthalate bonds. The dominant degradation reactions were those that involved the phosphate groups. This work constitutes the first application of mass spectrometry to the characterization of polyphosphoesters and demonstrates the suitability of high mass accuracy FT-ICR mass spectrometry, with CID and ECD, for the structural analysis of polyphosphoesters and their degradation products

Secondary Ion Mass Spectrometry Imaging of Dictyostelium discoideum Aggregation Streams

High resolution imaging mass spectrometry could become a valuable tool for cell and developmental biology, but both, high spatial and mass spectral resolution are needed to enable this. In this report, we employed Bi3 bombardment time-of-flight (Bi3 ToF-SIMS) and C60 bombardment Fourier transform ion cyclotron resonance secondary ion mass spectrometry (C60 FTICR-SIMS) to image Dictyostelium discoideum aggregation streams. Nearly 300 lipid species were identified from the aggregation streams. High resolution mass spectrometry imaging (FTICR-SIMS) enabled the generation of multiple molecular ion maps at the nominal mass level and provided good coverage for fatty acyls, prenol lipids, and sterol lipids. The comparison of Bi3 ToF-SIMS and C60 FTICR-SIMS suggested that while the first provides fast, high spatial resolution molecular ion images, the chemical complexity of biological samples warrants the use of high resolution analyzers for accurate ion identification

The Ramsey method in high-precision mass spectrometry with Penning traps: Experimental results

The highest precision in direct mass measurements is obtained with Penning trap mass spectrometry. Most experiments use the interconversion of the magnetron and cyclotron motional modes of the stored ion due to excitation by external radiofrequency-quadrupole fields. In this work a new excitation scheme, Ramsey's method of time-separated oscillatory fields, has been successfully tested. It has been shown to reduce significantly the uncertainty in the determination of the cyclotron frequency and thus of the ion mass of interest. The theoretical description of the ion motion excited with Ramsey's method in a Penning trap and subsequently the calculation of the resonance line shapes for different excitation times, pulse structures, and detunings of the quadrupole field has been carried out in a quantum mechanical framework and is discussed in detail in the preceding article in this journal by M. Kretzschmar. Here, the new excitation technique has been applied with the ISOLTRAP mass spectrometer at ISOLDE/CERN for mass measurements on stable as well as short-lived nuclides. The experimental resonances are in agreement with the theoretical predictions and a precision gain close to a factor of four was achieved compared to the use of the conventional excitation technique.Comment: 12 pages, 14 figures, 2 table