This review offers an introduction to the principles and generic applications of FT-ICR mass spectrometry, directed to readers with no prior experience with the technique. We are able to explain the fundamental FT-ICR phenomena from a simplified theoretical treatment of ion behavior in idealized magnetic and electric fields. The effects of trapping voltage, trap size and shape, and other nonidealities are manifested mainly as perturbations that preserve the idealized ion behavior modified by appropriate numerical correction factors. Topics include: effect of ion mass, charge, magnetic field, and trapping voltage on ion cyclotron frequency; excitation and detection of ICR signals; mass calibration; mass resolving power and mass accuracy; upper mass limit(s); dynamic range; detection limit, strategies for mass and energy selection for MSn; ion axialization, cooling, and remeasurement; and means for guiding externally formed ions into the ion trap. The relation of FT-ICR MS to other types of Fourier transform spectroscopy and to the Paul (quadrupole) ion trap is described. The article concludes with selected applications, an appendix listing accurate fundamental constants needed for ultrahigh-precision analysis, and an annotated list of selected reviews and primary source publications that describe in further detail various FT-ICR MS techniques and applications. © 1998 John Wiley & Sons, Inc., Mass Spec Rev 17, 1–35, 1998

Fourier transform ion cyclotron resonance mass spectrometry: A primer

Carbon Nanomaterials for Biological Imaging and Nanomedicinal Therapy

Fullerenes are entirely insoluble in water, but suitable functionalization makes the molecules soluble. Studies on water-soluble fullerene derivatives led to the discovery of the interaction of organofullerenes with DNA, proteins, and living cells, which was first reported in the summer of 1993. Subsequent studies have revealed interesting biological activity aspects of organofullerenes owing to their photochemistry, radical quenching, and hydrophobicity to form one- to three-dimensional supramolecular complexes. In these areas of research, synthetic organic chemistry has played an important role in the creation of tailor-made molecules.

Functionalized fullerenes in water. The first 10 years of their chemistry, biology, and nanoscience

Fullerene derivatives: an attractive tool for biological applications

This review describes the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to carbohydrate analysis and covers the period 1991-1998. The technique is particularly valuable for carbohydrates because it enables underivatised, as well as derivatised compounds to be examined. The various MALDI matrices that have been used for carbohydrate analysis are described, and the use of derivatization for improving mass spectral detection limits is also discussed. Methods for sample preparation and for extracting carbohydrates from biological media prior to mass spectrometric analysis are compared with emphasis on highly sensitive mass spectrometric methods. Quantitative aspects of MALDI are covered with respect to the relationship between signal strength and both mass and compound structure. The value of mass measurements by MALDI to provide a carbohydrate composition is stressed, together with the ability of the technique to provide fragmentation spectra. The use of in-source and post-source decay and collision-induced fragmentation in this context is described with emphasis on ions that provide information on the linkage and branching patterns of carbohydrates. The use of MALDI mass spectrometry, linked with exoglycosidase sequencing, is described for N-linked glycans derived from glycoproteins, and methods for the analysis of O-linked glycans are also covered. The review ends with a description of various applications of the technique to carbohydrates found as constituents of glycoproteins, bacterial glycolipids, sphingolipids, and glycolipid anchors.

Matrix-assisted laser desorption/ionization mass spectrometry of carbohydrates.

A diamido diacid diphenyl fulleroid derivative was designed specifically to inhibit an HIV enzyme. The detailed synthesis and mass spectrometric analysis of the water-soluble, biologically active methanofullerene are described. The compound was prepared in three steps from C[sub 60] via a suitably diphenyldiazomethane. High-resolution mass spectrometric analysis was possible only under mild matrix-assisted laser desorption/ionization Fourier transform mass spectrometry conditions. Direct infrared or ultraviolet laser desorption resulted exclusively in observation of C[sub 60] ions, in either positive or negative mode. 13 refs., 3 figs.

Synthesis of a fullerene derivative for the inhibition of HIV enzymes

High-resolution matrix-assisted laser desorption/ionization of biomolecules by Fourier transform mass spectrometry

Recent research has demonstrated that matrix-assisted laser desorption/ionization (MALDI) is feasible for Fourier transform mass spectrometric analysis of biomolecules with masses in excess of 50,000 Da. Here, the effects of electrostatic deceleration times and laser energy upon mass resolution are reported. It is demonstrated that optimum deceleration times for singly-charged MALDI-generated protein ions ranging in mass from 2627 to 29,000 Da are a linear function of m1/2 when a 9.5-V decelerating potential is used. Furthermore, higher resolution is obtained with laser fluences close to the threshold for MALDI. Slow metastable decay of molecular ions in the absence of co-matrix is demonstrated for melittin and bovine insulin. It appears that the resolution enhancing effect of co-matrix may result from slowing molecular ion unimolecular decomposition rates sufficiently to allow infrared emission to compete with metastable decay, thus providing the requisite population of long-lived ions for high mass resolution. A spectrum of bovine insulin molecular ion with mass resolution of 30,000 is presented, together with several spectra of lower mass proteins with mass resolution in excess of 100,000. Detection of a doubly-charged carbonic anhydrase trimer ion with a mass of 87,000 Da is reported.

Ultrahigh resolution matrix-assisted laser desorption/ionization of small proteins by Fourier-transform mass spectrometry

The advantages of matrix-assisted laser desorption/ionization (MALDI) and Fourier transform mass spectrometry (FTMS) are combined to create a powerful tool for the characterization of power samples. MALDI permits generation of intact, singly charged, high-mass (m/z 10 3 -10 4 ) ions of polar and nonpolar analytes, while GTMS provides unique high resolution and mass accuracy. Use of a gated deceleration potential allows for FTMS detection of MALDI-generated ions. However, when a single delay time is used between desorption/ionization and restoration of normal trapping potentials, mass discrimination is apparent for broad power distributions. Here, an integral method for obtaining molecular weight distributions of polymers by MALDI-FTMS is presented. By means of a simple procedure of averaging time domain transients obtained from a series of polymer sample spectra recorded at systematically varied gated deceleration times, accurate power distributions are obtained. The technique is demonstrated with several poly(ethylene glycol) samples containing oligomers with masses covering a 10 kDa mass range

John A. Castoro

Papers

Synthesis of a fullerene derivative for the inhibition of HIV enzymes

High-resolution matrix-assisted laser desorption/ionization of biomolecules by Fourier transform mass spectrometry

Ultrahigh resolution matrix-assisted laser desorption/ionization of small proteins by Fourier-transform mass spectrometry

Determination of Molecular Weight Distributions of Polymers by MALDI-FTMS

Synthesis of a Fullerene Derivative for the Inhibition of HIV Enzymes.